Vance, David J. MODERN AND HISTORIC TRENDS IN FORAMINIFERAL
DISTRIBUTIONS AND SEDIMENT DYNAMICS IN THE ALBEMARLE
ESTUARINE SYSTEM, NORTH CAROLINA. (Under the co-direction of Dr. Stephen
J. Culver and Dr. D. Reide Corbett) Department of Geology, March 2004.
Fifty-three stations were utilized to eharacterize the estuarine environment of the
Albemarle estuarine system (AES) using surface and down-core trends in foraminifera
and radionuclide tracers (" Pb, Cs, and “ Ra). Thirty-seven speeies were recognized
in the dead assemblages from 49 stations, 19 species comprised the living populations.
Cluster analysis of the surface samples indieated that the living populations were
characterized by four biofacies: the mixed marsh and estuarine, nearshore marine,
estuarine, and estuarine shoal. The dead assemblages were characterized by five
biofacies: the nearshore marine and inlet, estuarine shoal, estuarine, inner estuarine, and
marsh. Radionuclide tracers were analyzed for 27 eores and produced an average
sedimentation rate of 0.13 cm yr’' for the cores not in protected reaches of the AES.
Radionuclide tracer profiles indieative of resuspended sediments and below predicted
excess “ Pb inventories suggested that most core stations, except those in the proteeted
reaches of the estuary, signified a potential loss of sediment from the AES probably to the
deeper Pamlico Basin to the south. Therefore, based on the average sedimentation rate
for the AES and the regional rate of sea-level rise (0.32 to 0.46 cm yr''), the accumulation
rates in the AES appear to be influeneed by short-term storm events and long-term sea
level rise and basin subsidence. Aeeumulation rates exceed sea level rise where
aecommodation space allows or storm events and physical processes are less frequent and
so resuspension and mobilization is less prevalent.
Paleoenvironmental reconstruction of three cores from the central Albemarle
basin, based on the distribution of dead surface foraminiferal assemblages, indicated that
biofacies were recognizable in the cores, the inner estuarine biofacies and the estuarine
biofacies. Analysis of radionuclide tracers enabled calculation of accumulation rates for
the cores. Accumulation rates provided the framework to establish a geochronology for
each core in order to make paleoenvironmental interpretations.
Paleoenvironmental reconstruction of the westernmost core (ALB01S1C2)
indicated this station was possibly influenced by ephemeral deposition of a fresher
upstream biofacies overtop of a low-brackish estuarine biofacies or by increased
freshwater discharge since the early 1990’s due to increased storm activity. The two
cores in the central (ALBOl S3C2) and western (ALBOl S4C2) portion of Albemarle
Sound showed that, prior to the early 19*'’ century, Albemarle Sound had supported
calcareous foraminiferal species. These taxa were adapted to the higher salinities that
resulted from several inlets that were open adjacent to the AES prior to 1828.
On the basis of this study, foraminiferal distributions and radionuclide tracers are
useful for characterizing modem estuarine environments and form the framework for
interpreting paleoenvironmental changes in coastal sediments and in late Quaternary
deposits of coastal North Carolina and adjacent regions.
MODERN AND HISTORIC TRENDS IN FORAMINIFERAL DISTRIBUTIONS AND
SEDIMENT DYNAMICS IN THE ALBEMARLE ESTUARINE SYSTEM,
NORTH CAROLINA
A Thesis
Presented to
The Faculty of the Department of Geology
East Carolina University
In Partial Fulfillment
of the Requirements for the Degree
Master of Science in Geology
by
David J. Vance
March 22, 2004
3U2
’
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ñ. ^
/: V. t:-' i * Í ^
it# f/C J:
MODERN AND HISTORIC TRENDS IN FORAMINIFERAL DISTRIBUTIONS AND
SEDIMENTARY PROCESSES IN THE ALBEMARLE ESTUARINE SYSTEM,
NORTH CAROLINA
by
David J. Vance
APPROVED BY:
CO-DIRECTOR OF THESIS
Dr. Stephen J. Culver
Chairman Department of Geology
CO-DIRECTOR OF THESIS
COMMITTEE MEMBER
COMMITTEE MEMBER
DEAN OF THE GRADUATE SCHOOL TqJLM-^
Dr. Paul D. Tschetter
DEDICATION
“To the only wise God, our Saviour,
let there be glory and majesty,
dominion and power,
both now and ever. Amen.”
Jude 25
ACKNOWLEDGEMENTS
The author wishes to express his utmost gratitude to the United States Geological
Survey and the Cushman Foundation for Foraminiferal Research for providing funding
for this research. Thanks go to Jennifer Jett for her help while using the microfossil
collection at the Smithsonian Institution in the National Museum of Natural History,
Washington, D.C. Thanks to Erin Letrick, Chris Smith and Lorin Gaines for their
assistance in the field and in the lab. I would also like to say thanks to Dr. Michael
Holloman and the ECU Leo Jenkins Cancer Center for providing facilities and time to
make x-radiographs of sediment cores. Thanks also go to Tim Charles for his help using
the scanning electron microscope at the Department of Biology, East Carolina University.
Much credit is also due to Jim Watson, to whom I have gone countless times for
logistical support during my thesis.
I am very grateful for the assistance and advice of Dr. Stanley R. Riggs and Dr.
Martin A. Buzas while serving as members of my thesis committee. I would also like to
express my gratitude and thanks for the guidance, help, and tfiendship of co-director. Dr.
D. Reide Corbett. To co-director. Dr. Stephen J. Culver, I am extremely thankful to have
had the opportunity to study and learn from him. His leadership, support, and
constructive advice have made an indelible impression upon me and my work, present
and future.
Finally, thanks to everyone else who has encouraged me during my progress
toward completion of my masters thesis. Their support and friendship has been crucial to
my success. Among those especially are my parents, Jeff and Linda, brother Jason, and
my grandparents, Charles and Nelda. Their love and support has undoubtedly made this
achievement possible. To my friends, I am grateful and blessed for your friendship and
support. And for my church family at Christ Presbyterian and the Friday morning men’s
breakfast with my old Pastor Carl Brannon, they have all encouraged my faith with their
dedication to the Lord Jesus Christ and helped me to do as God’s Word proclaims:
“Whatever you do, do it all to the glory of God.”
TABLE OF CONTENTS
Pages
LIST OF FIGURES viii
LIST OF TABLES xv
CHAPTER 1: INTRODUCTION I
1.1 Stat3e.m3.ent of Purpose 11.2 Area of2ISnpveesctieigsation 81.3 Geologic Origin and Evolution 91.4 Physical Hydrology 15CHAPTER 2; CONCEPTS AND PREVIOUS STUDIES 222.1 Estuaries 222.2 Foraminiferal distributions 232.3 Paleoenvironmental applications and taphonomy 332.4 Radionuclide analysis of sediment accumulation 36CHAPTER 3: METHODOLOGY 433.1 Field Methods 433.2 Laboratory Methods 443.2.1 Foraminiferal Analysis 443.2.2 Radionuclide Analysis. ' 463.3 Foraminiferal Data 473.3.1 Cluster analysis 47Diversity and Equitability 48
3.3.3Biofacies VIFidelity and Constancy 50
CHAPTER 4: RESULTS AND INTERPRETATIONS 51
4.1 Environmental Variables 51
4.2 Surface Distribution of Living Foraminifera - General Observations 54
4.3 Surface Distribution of Dead Foraminifera - General Observations 56
4.4 Cluster Analysis of Surface Stations - Living Population 59
4.5 Cluster Analysis of Surface Stations - Dead Assemblage 68
4.6 Radionuclide and Sediment Trends 81
4.7 Down-core Foraminiferal Populations and Assemblages 117
4.8 Foraminiferal Taphonomy 119
4.8.1 Surface Assemblages 119
4.8.2 Down-core Assemblages 124
4.9 Paleoenvironmental Analysis of the Albemarle Cores 125
CHAPTER 5: DISCUSSION 129
5.1 Relationship of Environmental Conditions to Foraminiferal
Distributions 129
5.2 Paleoecological Implications; Relationship of Living and
Dead Biofacies to Environments 131
5.3 Fate of Sediment in the AES 132
5.4 Historical Record - Paleoenvironmental Implications 137
CHAPTER 6: SUMMARY AND CONCLUSIONS 141
REFERENCES 144
SYSTEMATICS 160
vi i
PLATES 196
APPENDIX A: Numbers of live specimens per sample, total number
picked, fraction picked, and specimens per 50 cm^ 202
APPENDIX B: Species proportions of live specimens expressed as relative
abundance (%) within each sample, numbers of species per sample
(S), and biofacies grouping 211
APPENDIX C: Numbers of dead specimens per sample, total number
picked, fraction picked, and calculated numbers of specimens
per 50 cm^ 220
APPENDIX D: Species proportions of dead specimens expressed as
relative abundance (%) within each sample, numbers of species per
sample (S), species diversity (H(S)), equitability (E), and biofacies
grouping 229
APPENDIX E: Radionuclide tracer data and grain-size data (% < 63 pm)
(from Letrick, 2003) for each of the 27 cores analyzed 238
LIST OF FIGURES
CHAPTER 1 : INTRODUCTION
1.1 Map of the Outer Banks and estuarine system of northeastern
North Carolina, showing coastal Segments to be studied by the
NCCGC Study beginning with Segment I in July and August
2001 2
1.2 Paleo-river systems of eastern North Carolina and the submarine
subaerial headlands that influence the present morphology of the
coastal system. The present AES is the drowned portion of the
paleo-Roanoke River valley system (modified from Riggs et al.,
1995) 3
1.3 Map of 53 sample stations in the AES used for foraminiferal and
radionuclide analyses 5
1.4 Map showing major embayments along the Atlantic and Gulf
Coasts and the structural arches that are responsible for their
development (modified from Ward et al., 1991) 10
1.5 The coastal plain of North Carolina is split into a northern and
southern province with younger Pliocene to Quaternary formations
exposed in the northern province and older Cretaceous to Miocene
formations in the southern province (from Riggs and Ames, 2003) 11
1.6 Map of the North Carolina Coastal Plain and its marine terraces.
The AES is situated east of the Suffolk Scarp (a paleo-shoreline) and
within the Pamlico Terrace (Beilis et al., 1975). (Note; map displays
some inlets that are not presently open) 13
1.7 Bathymetry of Albemarle Sound showing contours in meters. The
approximate extent of the perimeter platform corresponds with 1-2 m
water depth (from Giese et al., 1985) 16
1.8 Distribution of surface sediments in Albemarle Sound (from Geise
etal., 1985) 16
1.9 Map of seasonal variations in winds and salinity patterns, showing
dominant sources of tidal exchange and freshwater discharge (from
Wells and Kim, 1989) 19
IX
1.10 A) Surface isohalines in March. B) Bottom isohalines in March.
Salinities represent mean monthly data from 1955-1957 for
Albemarle Sound and 1941-1967 for Pamlico Sound (from
Williams et al., 1973) 20
1.11 A) Surface isohalines in December. B) Bottom isohalines in
December. Salinities represent mean monthly data from 1955-1957
for Albemarle Sound and 1941-1967 for Pamlico Sound (from
Williams et al., 1973) 21
CHAPTER 2: PREVIOUS WORKS
2.1 natural radioactive family or 4n-t-2 family (from Adolf and
Guillaumont, 1993) 38
2.2 Pathways by which ^“^Pb reaches the estuarine basin. (A) Particulate
erosive input. (B) Direct atmospheric fallout. (C) Indirect atmospheric
input, (1) is not retained by particulates in system and passes quickly
to the estuarine basin, (2) long residence time in the drainage basin
before being delivered to the estuarine basin. (D) Radon decay in the
water column (from Oldfield and Appleby, 1984) 38
CHAPTER 4: RESULTS AND INTERPRETATIONS
4.1 Dendrogram produced by cluster analysis (Ward’s linkage. Euclidean
distances) of transformed proportions data for the living foraminifera 60
4.2 Map showing distribution of four biofacies identified by cluster analysis
of all living foraminiferal data 61
4.3 Dendrogram produced by cluster analysis (Ward’s linkage. Euclidean
distances) of transformed proportions data for dead foraminifera. Only
those taxa comprising 5 percent or more assemblage in any on sample
were included 69
4.4 Map showing distribution of five biofacies identified by cluster analysis
including dead species comprising five percent or more of the assemblage
in any one sample 70
4.5 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ALBOISICI, and x-radiograph for
the core (scale in centimeters) in Albemarle Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'°Pb, samples within error of zero were not included in the plot
X
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 87
4.6 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ALB01S2C1, and x-radiograph for
the core (scale in centimeters) in Albemarle Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 88
4.7 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ALB01S3C1, and x-radiograph for
the core (scale in centimeters) in Albemarle Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^''’Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 89
4.8 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ALB01S4C1, and x-radiograph for
the core (scale in centimeters) in Albemarle Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'^Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 90
4.9 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ALLOISICI, and x-radiograph for
the core (scale in centimeters) in Alligator River. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'°Pb, samples within error of zero were not included in the plot.
No calculation of sedimentation rate was made for the core due to its
sandy nature and limited excess ^'°Pb activity 92
4.10 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ALL01S2C1, and x-radiograph for
the core (scale in centimeters) in Alligator River. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'®Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 94
4.11 Illustration of radionuclide tracer profiles, grain-size, expressed as a
XI
percentage of < 63 pm (mud) for ALL01S3C1, and x-radiograph for
the core (scale in centimeters) in Alligator River. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'®Pb, samples within error of zero were not included in the plot.
No calculations were made on this core due to the lack of excess ^'‘^Pb
activity 95
4.12 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ALL01S5C1, and x-radiograph for
the core (scale in centimeters) in Alligator River. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'®Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 96
4.13 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for EL02S1C1 in East Lake. No
x-radiograph was obtained for the core. Note changes in x-axes scale
from linear to log between both graphs. In the graph of excess ^'®Pb,
samples within error of zero were not included in the plot or
calculations. Sedimentation rates and R squared values are for the
slope of the linear regression 98
4.14 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for SL02S1C1 in South Lake. No
x-radiograph was obtained for the core. Note changes in x-axes scale
from linear to log between both graphs. In the graph of excess ^'°Pb,
samples within error of zero were not included in the plot or
calculations. Sedimentation rates and R squared values are for the
slope of the linear regressions 99
4.15 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for PASOISICI, and x-radiograph for
the core (scale in centimeters) in Pasquotank River. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'^Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regressions 101
4.16 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for PAS01S2C1, and x-radiograph for
the core (scale in centimeters) in Pasquotank River. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
xii
21 o
excess Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 103
4.17 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for PASOl S3C1, and x-radiograph for
the core (scale in centimeters) in Pasquotank River. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^''^Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 104
4.18 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for NOROISICI, and x-radiograph for
the core (scale in centimeters) in North River. Note changes in x-axes
scale from linear to log between both graphs. In the graph of excess
^'®Pb, samples within error of zero were not included in the plot or
calculations. Sedimentation rates and R squared values are for the slope
of the linear regression 106
4.19 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for NOR01S2C1 in North River. No
x-radiograph was obtained for the core. Note changes in x-axes scale
from linear to log between both graphs. In the graph of excess ^'^Pb,
samples within error of zero were not included in the plot or
calculations. Sedimentation rates and R squared values are for the
slope of the linear regression 107
4.20 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for CUROISICI, and x-radiograph for
the core (scale in centimeters) in Currituck Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'^Pb, samples within error of zero were not included in the plot.
No calculation of sedimentation rate was made for the core due to its
sandy nature and limited excess ^"^Pb activity 109
4.21 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for CUR01S3C1 in Currituck Sound. No
x-radiograph was obtained for the core. Note changes in x-axes scale
from linear to log between both graphs. In the graph of excess ^''^Pb,
samples within error of zero were not included in the plot or
calculations. Sedimentation rates and R squared values are for the
slope of the linear regression no
Xlll
4.22 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for CUR01S5C1, and x-radiograph for
the core (scale in centimeters) in Currituck Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'°Pb, samples within error of zero were not included in the plot.
No calculation of sedimentation rate was made for the core due to its
sandy nature and limited excess ^'°Pb activity 111
4.23 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for CURO 1 SSCI, and x-radiograph for
the core (scale in centimeters) in Currituck Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^'^^Pb, samples within error of zero were not included in the plot.
No calculation of sedimentation rate was made for the core due to its
sandy nature and limited excess ^'°Pb activity 112
4.24 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for CRO01S3C1 in Croatan Sound. No
x-radiograph was obtained for the core. Note changes in x-axes scale
from linear to log between both graphs. In the graph of excess ^'°Pb,
samples within error of zero were not included in the plot. No calculation
of sedimentation rate was made for the core due to its sandy nature and
limited excess ^'^Pb activity 113
4.25 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for CRO01S6C1, and x-radiograph for
the core (scale in centimeters) in Croatan Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^''^Pb, samples within error of zero were not included in the plot.
No calculation of sedimentation rate was made for the core due to its
sandy nature and limited excess ^'®Pb activity 114
4.26 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ROAOISICI, and x-radiograph for
the core (scale in centimeters) in Roanoke Sound. Note changes in
x-axes scale from linear to log between both graphs. In the graph of
excess ^''^Pb, samples within error of zero were not included in the plot.
No calculation of sedimentation rate was made for the core due to its
sandy nature and limited excess ^''^Pb activity 115
4.27 Illustration of radionuclide tracer profiles, grain-size, expressed as a
percentage of < 63 pm (mud) for ROA01S4C1, and x-radiograph for
the core (scale in centimeters) in Roanoke Sound. Note changes in
XIV
x-axes scale from linear to log between both graphs. In the graph of
excess ^'^Pb, samples within error of zero were not included in the plot
or calculations. Sedimentation rates and R squared values are for the
slope of the linear regressions below the upper two intervals with
decreased ^'°Pb activity that correlates with an increase in grain-size 116
CHAPTER 5: DISCUSSION
5.1 Landsat 7 image provided by NASA eastern North Carolina on
September 19, 2003 one day after Hurricane Isabel passed directly over.
Note sediment plume in Albemarle Sound is the result of shoreline
erosion of Chowan River bluff sediments by the category 2 hurricane
and the minor amounts of suspended sediment exiting through the
inlets (MODIS Image Gallery, 2003) 136
5.2 Map showing historic inlets and their geographic distribution
through time along the Outer Banks of North Carolina (Dolan,
1995 after Fisher, 1962) 139
LIST OF TABLES
CHAPTER 1 : INTRODUCTION
1.1 Summary of analyses conducted at each of the 53 stations in the
AES. Forty-nine stations were used to study foraminiferal
distributions, 27 stations were used for radionuclide tracer
studies, and three cores were used for paleoenvironmental
reconstruction 6
CHAPTER 4; RESULTS AND INTERPRETATIONS
4.1 Salinity, temperature, and dissolved oxygen measurements taken
at time of sampling 52
4.2 Stations were grouped into biofacies (B) through cluster analysis
of the living populations composed of all species. Interpretations
for each biofacies, number of species (S), number of specimens
picked (N), and calculated numbers of specimens per 50 cm^ (n)
are listed for each station 62
4.3 Average relative abundance of species per biofacies for the living
populations. Values expressed as an average percent of all the
samples in a given biofacies; the most abundant values are in bold 64
4.4 Occurrence (O), constancy (C), and biofacies fidelity (BE) for the
four biofacies that characterized the living populations 66
4.5 Stations were grouped into biofacies (B) through cluster analysis
of the dead assemblages including only those species whose
abundance was greater than 5 percent in any one sample.
Interpretations for each biofacies and values for species diversity
(H(S)), equitability (E), number of species (S), number of specimens
picked (N), and calculated numbers of specimens per 50 cm^ (n) are
listed for each station 71
4.6 Average relative abundance for the 37 species of the dead assemblages
in each biofacies. Values expressed as an average percent of all the
samples in a given biofacies. Values for the five most abundant species
are in bold for each biofacies 74
4.7 Occurrence (O), constancy (C), and biofacies fidelity (BE) for the
five biofacies that characterized the dead assemblages 75
XVI
4.8 Radionuclide data for excess and '^^Cs are presented for 22 of
27 cores. The remaining five cores were from the perimeter platform
and back-barrier shoals with no appreciable radionuclide activity.
Initial activity is presented to show the variability within the system
and excess ^'°Pb inventories were calculated for the whole core 83
4.9 Sedimentation rates were calculated for excess Pb using the CF-CS
model and for '^^Cs by using the '^’Cs peak when present in the cores
to compare with the excess ^’^b rates. All sedimentation and mass
accumulation rates were based on core midpoint intervals and should
be considered maximum rates. Calculation intervals of excess ^'°Pb
in cores represents the intervals for which sedimentation rates were
calculated. In some cases the excess ^'^Pb profiles were subdivided
based on breaks in slope and rates were calculated accordingly.
Errors and (based on linear regression) values are presented for
each interval. No sedimentation or accumulation rates were calculated
for sandy cores or where activity was limited to only the first interval 84
4.10 Living foraminiferal populations recorded at depth in three cores in the
western (ALB01S1C2) and central (ALB013C2 and ALB01S4C2)
Albemarle Sound. Fraction picked (FP), number of species (S), number
of living specimens picked (N), and calculated number of specimens per
-3
50 cm (n) are listed for each interval where specimens were found 118
4.11 List of three cores and counts of specimens per species from the dead
down-core assemblages for each interval 120
4.12 Dead subsurface foraminifera. List of cores and calculations of species
proportions, species diversity (H(S)), equitability (E), total number of
specimens picked (N), calculated numbers of specimens per 50 cm^,
and biofacies grouping with the surface greater than 5 percent dead
assemblages. In cases where a species’ proportions within a sample
was less than half of a percent and X was used to represent that value... 121
CHAPTER 1
INTRODUCTION
1.1 Statement of Purpose
In the summer of 2001, the North Carolina Coastal Geology Cooperative (NCCGC)
between East Carolina University (ECU), the United States Geological Survey (USGS) and
the North Carolina Geological Survey (NCGS) was initiated on the northeastern portion of
the Outer Banks of North Carolina (Figure 1.1), including the Albemarle Estuarine System
(AES). The goals of this project are to characterize all estuarine and marine environments in
the system, define the geologic framework controlling the modem coastal system, and
describe the modem processes that are driving ongoing coastal change. To do this, various
methods were employed such as, geophysics - utilizing ground penetrating radar (GPR),
uniboom seismic, and chirp sonar; stratigraphy - analyzing cores taken through the
Quaternary section; micropaleontology - documenting the modem and fossil benthic
foraminiferal assemblages; geochemistry - using short-lived radiochemical tracers ‘ Pb and
'^^Cs and stable isotope geochemistry; and sedimentology - mapping distribution patterns of
sediments in the system. This compilation of data will allow for a more comprehensive and
thorough examination of sea level and climate fluctuations throughout the Quaternary and
their impact on coastal sedimentary processes. The record of sea level change will be
derived from the stratigraphic record obtained from cores of Pleistocene and Holocene
channel fills of the paleo-Roanoke River (Figure 1.2) and other paleo-creeks and -rivers that
lie buried underneath the Outer Banks. Paleoenvironmental interpretation of these cores will
be aided by an understanding of the modem distribution of foraminifera in the study area.
2
Currituck
Pasquotank North tSound
River\ River r-
Little %
O
Perquimans o
Chowan / j
River RiverX,, X, xX-, AX \Yeopim ' ^ Kitty Hawk
River, ' xC'
SEGMENT I
Roanoke
Albemarle Sound
Sound
Roanoke 36°00’-
River ' Roanoke
Island
X \\ .Bodie
Island
¿ Oregon
\ Inlet
Sound '^\Pea
Island
35°00’-
llTs Cape Lookout 0 5 10 20 30 40
Kilometers
7rpo’ 7600’
Figure 1.1. Map of the Outer Banks and estuarine system of northeastern North Carolina, showing coastal
Segments to be studied by the NCCGC Study beginning with Segment I in July and August 2001.
3
Virginia
CURRITUCK
NORTH CAROLINA SUBMARINE
HEADLAND
COASTAL SYSTEM
ROA NOKE/A LB EMA RLE
VALLEY FILL 36*00’
DARE
SUBMARINE
HEADLAND
Cape Halteras
NEUSE/PAMLICO VALLEY FILL 35’00’—
CROATAN
SUBMARINE
HEADLAND
WHITEOAK/NEW RIVER VALLEY FILL
ONSLOW SUBMARINE HEADLAND 34‘CIO’
FORT FISHER
BRUNSWICK SUBAERIAL
SUBMARINE CAPE FEAR HEADLAND
HEADLAND VALLEY FILL
78*00’ 77*00’ 76*00’ 75*00’
_J I _|
Figure 1.2. Paleo-river systems of eastern North Carolina and the submarine and subaerial headlands
that influence the present morphology of the coastal system. The present AES is the drowned portion
of the paleo-Roanoke River valley system (from Riggs et al., 1995).
4
This knowledge will ultimately be used to guide a wide range of management decisions and
scientific activities at institutions and at the local, state, and federal levels.
This thesis project was begun in year 1, in segment 1 (Figure 1.1 ) of the
comprehensive NCCGC study and utilized 53 stations (Figure 1.3, Table 1.1) within the
study area. It involved characterizing benthic foraminiferal assemblages (surficial and
infaunal) throughout the AES at 49 stations (Figure 1.3, Table 1.1), the adjacent foreshore
and the inner shelf of the Atlantic Ocean. Variations in physio-chemical parameters such as,
salinity, sediment characteristics, temperature, current and wave energy, food availability,
water depth, tidal inundation and exposure in these environments are thought to define
subenvironments in the AES that correspond to particular foraminiferal assemblages. In
addition, this study investigated sediment radiochemistry at 27 stations (Figure 1.3, Table
1.1) to determine accumulation rates over the last 100 to 120 years (utilizing ^'®Pb and '^^Cs
radionuclide tracers). This will provide a temporal framework to understand the age of
sediments in short cores and thus reconstruct paleoenvironmentai changes (e.g., marine to
estuarine conditions due to inlet closings or vice-versa due to openings and storm events,
etc.) in three short sediment cores from Albemarle Sound. Modem foraminiferal distribution
patterns will ultimately serve as a model to facilitate interpretations of Quaternary
paleoenvironments penetrated in cores drilled by the NCOS on the Outer Banks (Culver et
al., 2002). Thus, three basic objectives were pursued;
1. Use foraminiferal distribution patterns to distinguish modem subenvironments within
the AES.
5
Figure 1.3. Map of 53 sample stations in the AES used for foraminiferal and radionuclide analyses.
6
Table 1.1. Summary of analyses conducted at each of the 53 stations. Forty-nine stations were used
to understand foraminiferal distributions, 27 stations were used for radionuclide tracer and grain-
size studies, and three cores were used for paleoenvironmental reconstruction.
Surface Analyses Down-core Analyses
Station Foraminiferal Radionuclide Foraminiferal Radionuclide Core Grain-size
Distribution Tracers Analysis Tracers X-ray (Letrick, 2003)
BEAOISI X
BEA01S2 X
BEA01S3 X
INSOISI X
EBBOISI X
OFFOISI X
ALBOISI X X X X X X
ALB01S2 X X X X X
ALB01S3 X X X X X X
ALB01S4 X X X X X X
ALB01S5 X X X X
ALB01S6 X X X X
ALB01S8 X X X X
ALLOISI X X X X X
ALL01S2 X X X X X
ALLO1S3 X X X X X
ALL01S4 X X X X
ALL01S5 X X X X X
EL02S1 X X X
SL02S1 X X X
PASOISI X X X X X
PAS01S2 X X X X X
PASO1S3 X X X X X
NOROIS 1 X X X X X
NOR01S2 X X X X
CUROISI X X X X X
CUR01S2 X
CLFR01S3 X X X
CUR01S4 X
CUR01S5 X X X X X
CUR01S6 X
CUR01S7 X
CUR01S8 X X X X
CUR01S9 X
CUROISIO X
CROOISI X
CRO01S2 X
CROO 1 S3 X X X X
CRO01S4 X
7
Table 1.1. Continued.
Surface Analyses Down-core Analyses
Station Foraminiferal Radionuclide Foraminiferal Radionuclide Core Grain-size
Distribution Tracers Analysis Tracers X-ray (Letrick, 2003)
CRO01S6 X X X X X
CRO01S7 X
ROAOISI X X X X X
ROA01S2 X
ROA01S4 X X X X X
ROA01S5 X
ROA01S7 X
ROA01S9 X
PAM01S2 X
PAM01S5 X
PAM01S6 X
PAM01S7 X
PAM01S8 X
PAM01S9 X
8
2. Use radiochemical tracers to assess accumulation rates from short cores and patterns
of net deposition or erosion in the AES.
3. Use modem foraminiferal assemblages to interpret paleoenvironmental change in
short cores.
1.2 Area of Investigation
Located in northeastern North Carolina at approximately 36° N latitude and 76° W
longitude (Figure 1.1), the AES represents a large network of open water sounds fed by many
creeks and rivers. The northern section of the Outer Banks in this region has only one inlet,
Oregon Inlet, located 5.8 km southeast of Roanoke Island. It is the only outlet to the Atlantic
Ocean for the 173 km of coastline comprising the northern estuarine system. Oregon Inlet is
approximately 93 km SSE of the Virginia state line and approximately 80 km up the
coastline from Hatteras Inlet (Figure 1.1) (Singer and Knowles, 1975).
The estuarine shoreline is 800 km (500 mi) long and composed of five shoreline types
and morphologies: marsh (26%), low bank (36%), high bank (14%), bluff (1%), and swamp
forest (23%) (Riggs, 2001). The main tmnk of the AES is Albemarle Sound, which is
oriented roughly east to west and perpendicular to the adjacent barrier islands of the Outer
Banks. Albemarle Sound extends from the mouth of the Roanoke and Chowan Rivers,
eastward for 90 km to Kitty Hawk Bay on the Outer Banks (Figure 1.3). The sound ranges
from 5 km wide in the west to over 20 km wide in the vicinity of the Alligator, North, and
Pasquotank Rivers (Copeland et al., 1983). The AES includes nine major embayed lateral
estuaries from west to east, including the Chowan, Yeopim, Perquimans, Little, Pasquotank,
9
and North Rivers on the north and the Roanoke, Scuppemong, and Alligator Rivers on the
south (Figure 1.1). To the east, the AES is composed of three open water sounds parallel to
the Outer Banks. To the north is the predominantly low brackish Currituck Sound and to the
south are the variably brackish Roanoke and Croatan Sounds. Croatan Sound provides the
dominant hydrologic connection for the AES to Pamlico Sound and the Atlantic Ocean
through Oregon Inlet (Figure 1.1).
1.3 Geologic Origin and Evolution
The coastal plain of North Carolina is situated within the Albemarle Embayment
(Figure 1.4), a major Pliocene-Pleistocene depositional basin created by the Norfolk Arch to
the north and the Cape Lookout High to the south (Ward et al., 1991). The coastal plain is
split into two provinces, a northern and southern (Figure 1.5) by the Cape Lookout High or
Neuse Arch (an Oligocène paleotopographic high) (Sohl and Owens, 1991 ; Riggs et al.,
1995; Riggs, 2002). This paleotopographic high on top of the Oligocène was the effective
margin of the Albemarle Embayment during most of the Pliocene and is located on the north
flank of the Cape Fear Arch (Ward et al., 1991). To the south of the Cape Lookout High, the
coastal plain stratigraphy is influenced by the Carolina Platform High (a major Mesozoic
basement structural feature) and consists of exposed Cretaceous and Tertiary units with only
thin remnants of Quaternary sediments (Ward et al, 1991; Riggs, 2002). Conversely, the
northern province is characterized by a thick (50-70 m) Quaternary section (Riggs et ah,
1995).
10
Figure 1.4. Map showing major embayments along the Atlantic and Gulf Coasts and the structural arches
that are responsible for their development (modified from Ward et al., 1991).
11
Figure 1.5. The coastal plain ofNorth Carolina is split into a northern and southern province with younger
Pliocene to Quaternary formations exposed in the northern province and older Cretaceous to Miocene
formations with some thin Quaternary exposures in the southern province (from Riggs and Ames, 2003).
12
The geologic framework created by the distinct geology of each province produces
quite different coastal morphologies. The southern province has common exposures of the
older rock units along the shoreline and steeper land slopes (average 0.57 m km''). This
geologic framework produces about 18 short barrier islands with 18 established inlets and
narrow back-barrier estuaries (Riggs, 2002). The northern province is characterized by a
gentle depositional topography with low land slopes (average 0.04 m km'') and long, narrow
islands separated by only four established inlets producing a semi-isolated Albemarle-
Pamlico estuarine system (Riggs, 2002).
Situated in the northern coastal province on the Pamlico Terrace and bounded on the
west by the Suffolk Scarp (Figure 1.6), the trunk of the AES occupies the river valley and
associated flood plain of the paleo-Roanoke River (Figure 1.2) (Copeland et al., 1983; Riggs
et al., 1995). The morphology of the AES is inherited from the paleo-river drainages which
have eroded into the complex and irregular framework of Plio-Pleistocene sediments
(Copeland et al., 1983; Ward et al., 1991; Riggs et al., 1995; Riggs, 2002). These sediments
range from gravel, sand, clay, and peat and represent fluvial, estuarine, barrier island, and
continental shelf depositional environments (Ward et al., 1991). This framework is the result
of multiple transgressive and regressive events caused by large amplitude oscillations in sea
level (Fairbanks, 1989; Riggs et al., 1992; Boss et al., 2002) and the resulting incision and
infill associated with the paleo-fluvial and estuarine response to these processes (Mallinson et
al., submitted). The surficial Pleistocene sediments are largely from the last glacial period
that produced a cold, semi arid, boreal climate over this region (Riggs, 2002). This interval
was characterized by limited vegetation cover, increased episodic surface water discharge
13
Figure 1.6. Map of the North Carolina Coastal Plain and its marine terraces. The AES is situated east of the
Suffolk Scarp (a paleo-shoreline) and within the Pamlico Terrace (from Beilis et al., 1975). (Note; map
displays some inlets that are not presently open.)
14
and increased sediment yields, producing sediment choked braided streams in the paleo-
Roanoke River valley (Copeland et al., 1983).
The present AES began to take its form after the last glacial maximum (~15,000-
17,000 years BP) when the paleo-Roanoke River valley was partially filled by late
Pleistocene to Holocene sediments as it was slowly drowned by sea level rise, creating an
estuarine system characterized by embayed tributaries and open water sounds. The thickness
of the Holocene sediments varies considerably within the AES and is mostly limited to the
paleo-channel fills (Sager and Riggs, 1998). In the axis of the paleo-Roanoke River channel
underlying Albemarle Sound, the thickness of sediment is 35 m (Mallinson et al., submitted)
and is as great as 50 m under the shoreface east of the barrier islands (Boss et al., 2002)
(Figure 1.1). Thicknesses gradually thin to the north, south, and west as the Holocene
sediments impinge on the Pleistocene framework, and gently deepen eastward beyond the
barrier island (Boss et al., 2002; Mallinson et al., submitted.).
Much of Albemarle Sound and its embayed tributaries are surrounded by a
submerged perimeter platform ranging from 1-2 m in depth (Figure 1.7) (Riggs, 1996). This
narrow platform is formed by Pleistocene sediments but is usually covered by a thin layer of
recent sand eroded from the sediment bank shorelines (Sager and Riggs, 1998). From the
perimeter platform in Albemarle Sound, the estuary bottom slopes gently toward a flat
bottom in the central basin (with an average basin depth of 6 m). Embayed tributaries have a
similar morphology with average depths of 2 to 4 m (Riggs, 1996).
Sediment entering the AES comes predominantly from two sources, rivers and
shoreline erosion (Riggs, 1996; Riggs and Ames, 2003). The Roanoke and Chowan Rivers
15
supply a majority of the suspended sediments entering the estuary compared to the other
rivers that feed into the AES (Riggs, 1996). This suspended sediment is mixed with organic-
rich sediments eroded from the swamp forests and eroding marshes (Copeland et ah, 1983;
Riggs, 1996), producing organic rich mud (ORM) that forms the dominant (70%) sediment
type of the Albemarle Sound basin and embayed estuaries (Riggs, 1996). Nearly all
shorelines within the estuary are eroding, but erosion rates vary based on shoreline type,
geographic location, orientation, and exposure to wave energy (Riggs, 2002; Riggs and
Ames, 2003). Erosion rates have been shown to have a direct correlation to fetch; thus
erosion rates increase as the estuarine system widens (Riggs and Ames, 2003). The
innermost reaches of the estuarine system tend to erode the slowest at <0.30 m yr ' (Riggs
and Ames, 2003). The Albemarle Sound region has an average erosion rate of 1.2 m yr '
(Riggs and Ames, 2003). Sediment patterns in the system follow depth contours with the
coarsest sediments at the shorelines, on the perimeter platform and shoals, and finest in the
central basin of Albemarle Sound and the embayed tributaries (Figure 1.8). Wave processes
in response to wind events are largely responsible for mobilizing, sorting, and transporting
sediment on the estuarine bottom as indicated by the distribution (Wells and Kim, 1989).
1.4 Physical Hydrology
The AES is an oligohaline estuary, whose physical hydrology and circulation is
governed predominantly by three factors: fresh water inflow, winds, and astronomical tides
(Wilder, 1968). Fresh water inflow is the dominant force in long-term circulation in the AES
(Giese et al., 1985). Discharge into the AES is much higher than any other sound system in
16
Figure 1.7. Bathymetry ofAlbemarle Sound showing contours in meters. The approximate extent of the
perimeter platform corresponds with 1-2 m water depths (modified from Giese et al., 1985).
Figure 1.8. Distribution of surface sediments in Albemarle Sound (fi-om Giese et al., 1985).
17
North Carolina (Giese et al., 1985). The majority of the inflow is contributed by two of three
major watersheds that form the drainage basin of the AES. The Roanoke River, draining
25,220 km , discharges between 1.5 and 1892.5 million m day’ (Bowden and Hobbie,
1977), with annual average of 21.8 million m^ day’‘ being delivered to the AES (Giese et ah,
1985). The Chowan River drains half the area as the Roanoke River (12,740 km^)
discharging an annual average of 11.2 million m^ day’'. The Albemarle Basin, draining
7,540 km , is formed by the remaining tributary coastal plain rivers flowing into the
Albemarle Sound ifom north and south. Thus, the entire effective watershed of the AES is
the largest watershed in North Carolina stretching to the foothills of the Appalachians,
collectively draining 45,500 km^ (Bowden and Hobbie, 1977; Riggs, 1996). Croatan and
Roanoke Sounds are the outflow conduits for an average annual discharge of 41.6 million m^
day ' from the AES into Pamlico Sound and the Atlantic Ocean via Oregon Inlet (Giese et al.,
1985).
The AES has a large surface area and moderately uniform depths, which provides
adequate fetch and water depths to create wind driven waves and wind tides (Riggs, 2002).
Depending on their speed and duration, wind events create the major water level changes
with minimal astronomical tides (Riggs and Ames, 2003). Thus, winds exert the major
influence on short-term circulation and play an integral role in mixing the estuary, causing
physio-chemical gradients in the water column to be small (Bowden and Hobbie, 1977).
Due to the large hydraulic head, there is limited free exchange of ocean water through
Oregon Inlet, and astronomical tidal amplitudes decrease rapidly away from the inlet
(Wilder, 1968). The tidal range on the flood tide delta of Oregon Inlet has a mean tidal range
18
of 0.61 m and a spring tidal range of 0.73 m (Singer and Knowles, 1975). Tidal influence on
circulation and salinities in the AES is greatest in the sound system adjacent to Oregon Inlet,
but tidal influence though minimal can be seen as far west as the Chowan River estuary
(Giese et al., 1985).
Physio-chemical parameters in Albemarle Sound also vary as a function of the
seasons and in response to short-term storm events. Stratification in the estuary is minimal
and transitory at best with temperature variations between top and bottom rarely more than 2-
3°C (Bowden and Hobbie, 1977; Giese et al., 1985). Seasonal temperatures variations in the
AES exhibit surface maximums of 30-35°C between July to August and surface lows around
January of 0.5-6‘’C. Seasonal salinity patterns fluctuate with changes in freshwater inflow,
while short-term patterns are influenced mainly by winds (Figure 1.9). Minimum salinities
are typically recorded in March when runoff from spring rains displaces more saline water
eastward (Figures 1.10) (Giese et al., 1985). Maximum salinities are recorded in December
when low fresh water inflows from the summer and fall allow the encroachment of more
saline waters from Pamlico Sound and Oregon Inlet into Albemarle Sound (Figures 1.11)
(Giese et al., 1985). The lowest salinities in the AES are typically in the far west of the
system and at the heads of all the embayed tributaries. Salinities increase gradually toward
the east and become higher in the southern sounds with direct connection to Pamlico Sound
and Oregon Inlet where the salinities are usually greater than 14 (Williams et al., 1973).
19
Figure 1.9. Map of seasonal variations in winds and salinity patterns, showing dominant sources of
tidal exchange and freshwater discharge (from Wells and Kim, 1989).
Figure 1.10. A) Surface isohalines in March. B) Bottom isohalines in March. Salinities represent mean monthly data from 1955-1957 for Albemarle
Sound and 1941-1967 for Pamlico Sound (from Williams et al., 1973). to
o
Figure 1.11. A) Surface isohalines in December. B) Bottom isohalines in December. Salinities represent mean monthly data from 1955-1957 for
Albemarle Sound and 1941-1967 for Pamlico Sound (from Williams et al., 1973). KJ
CHAPTER 2
CONCEPTS AND PREVIOUS STUDIES
2.1 Estuaries
The term estuary has traditionally been defined as the lower reaches of a river that
is intruded by salt water that mixes with the seaward flowing ifesh water (Officer, 1976).
There are over 40 definitions of estuaries today (Perillo, 1995), reflecting the varied
perspectives scientists have on this marginal marine environment. The most commonly
adopted definition of estuaries is by Cameron and Pritchard (1963): “An estuary is a
semi-enclosed coastal body of water which has a free connection to the open sea and
within which sea water is measurably diluted with fresh water derived from land
drainage.” Perillo (1995) amplified this definition by stating, “An estuary is a semi-
enclosed body of water that extends to the effective limit of tidal influence, within which
sea water entering from one or more free connections with the open sea, or any other
saline coastal body of water, is significantly dilute with fresh water derived from land
drainage, and can sustain euryhaline biological species for either part or the whole of
their life cycle.” Bodies of water commonly considered estuaries today include bays,
bayous, gulfs, inlets, lagoons, sounds, and some lakes. The degree of free connection
between each of these estuaries and the open sea varies between wide-open and
restricted.
Estuaries throughout the world display a wide range of form, owing to the
complex interaction of riverine and marine processes influenced in part by the geologic
framework giving each estuary its own unique physical, biological, and chemical
23
characteristics. These riverine and marine processes produce ecologically rich habitats
for many forms of marginal marine and marine vertebrates and invertebrates. Estuaries
are also where nutrients, anthropogenic or natural, enter the marine environment, bolster
productivity and in some cases cause environmental degradation. Due to the physical and
chemical variations within the estuarine system, only the best-suited organisms are most
abundant, where others occupy a particular niche where they can only survive. The
estuary can usually be subdivided on the basis of faunal (particularly microfaunal)
communities whose distribution is largely a result of the salinity gradient along the
estuary.
Over the past several decades foraminiferal researchers have documented the
distribution of benthic foraminifera in estuarine environments to serve as the basis for
paleoenvironmental reconstructions of past estuarine conditions, for analysis of the
estuarine health, and to serve as a baseline for monitoring in the future.
2.2 Foraminiferal distributions
In the geologic record, it can be very difficult to differentiate between the
different depositional environments present in a coastal system (salt and Iresh water
marsh, embayed estuary, sound, river, and barrier island facies) on the basis of
sedimentological characteristics alone. Benthic foraminifera have proven to be good
indicators for characterizing different coastal environments (see Scott et al., 2001, for
their treatment of the subject). Marginal marine environments along the North American
Atlantic coast and the Gulf of Mexico (see Culver and Buzas, 1980, 1981, for a
24
summary) as well as Europe (see Murray, 1991, for a summary), have been studied to
discern ecological relationships between species and environmental variables and to
define biofacies that are useful for paleoenvironmental interpretation.
Benthic foraminifera were chosen to characterize estuarine environments in this
study because of their proven usefulness as indicators of modem and ancient
environmental conditions. Foraminifera are testate protozoans that are able to live in a
wide range of environmental conditions from brackish to marine environments. Some
species exist over a broad geographic range while others have more restricted
distributions (Culver and Buzas, 1980 and 1981).
Foraminiferal ecology and distributions have been studied throughout the coastal
regions of North America, because these environments represent transitional zones whose
ecological conditions can have great variability. Not only is there great variability within
an estuary but also between estuaries, and this may be reflected in faunal differences, thus
underscoring the necessity of detailed studies of regional estuarine habitats. Numerous
North American studies have been focused in brackish bayous and lakes (e.g., Warren,
1957; Kane, 1967), bays and lagoons (e.g., Parker, 1952b; Miller, 1953; Ronai, 1955;
Poag, 1978; Buzas and Severin, 1982; Haman, 1983; Culver et ah, 1996; Woo et ah,
1997), embayed rivers and sounds (e.g.. Buzas, 1965; Grossman and Benson, 1967;
Nichols and Norton, 1969; Buzas, 1969; Ellison and Nichols, 1970; Akers, 1971),
marshes (e.g., Parker and Atheam, 1959; Scott and Medioli, 1978; Scott et ah, 1991;
Goldstein and Frey, 1986; Goldstein and Watkins, 1995, 1998), and nearshore marine
environments (e.g., Schnitker, 1971; Culver, 1988; Culver and Snedden, 1996). In each
25
of these studies, biofacies or faunal zones characterized foraminiferal distribution
patterns.
It has been shown by many of these studies that foraminiferal assemblages are
controlled by a number of interdependent variables (i.e., physical, biological, and
chemical) (Culver, 1993; Culver and Buzas, 1999; Sen Gupta, 1999). These conditions
are known to vary with latitude (e.g., Goldstein and Frey, 1986; Murray, 1991), thus
affecting the composition of foraminiferal assemblages from region to region (though
differences may be small). The aim of this study is to document the distribution of
modem foraminifera in the AES and to use these patterns to reconstruct past estuarine
environmental conditions. Thus, it is important to summarize what is known of modem
microfaunal assemblages from similar coastal environments.
In North Carolina, six foraminiferal studies (Miller, 1953; Grossman and Benson,
1967; Akers, 1971; Schnitker, 1971; LeFurgey, 1976; Workman, 1981) have documented
the distribution of foraminifera from the marshes and coastal estuaries to the shallow
continental shelf of North Carolina. In the southern coastal province. Miller (1953)
studied the ecology of benthic foraminifera around Mason Inlet and the associated
brackish lagoonal and marsh environments. He recorded 42 species ranging from
brackish to open ocean affinities. Miller (1953) did not define any foraminiferal
assemblages but noted that of the nine sample stations, those that represented similar
environments had similar assemblages. Akers (1971) studied 21 sites in and near the city
of Beaufort to discern foraminiferal assemblages. His study focused on the occurrence of
the foraminiferal species (living and dead) with changing salinities, sediment type.
26
physical environments, and infaunal occurrence in marsh sediments. He found that three
foraminiferal assemblages, an open-ocean, lagoonal, and a fluvial marine were present
along a salinity gradient between shallow nearshore open-ocean and the fluvial marine
system of Neuse River. In addition to these three, Akers (1971) characterized a marsh
assemblage which was similar to the fluvial marine assemblage.
Grossman and Benson (1967) studied the ecology of foraminifera and ostracoda
at 159 stations in the southern Pamlico Sound region. Five foraminiferal assemblages
were recognized ranging from the heads of estuaries (0.5 salinity) to the ebb tidal delta of
Ocracoke Inlet (36 salinity); an estuarine biofacies, an open-sound biofacies, a salt-water
lagoon biofacies, a tidal delta biofacies, and a marsh biofacies. They noted that salinity,
vegetation, and tidal currents were the most effective factors in determining the
distribution of the biofacies. They ascribed low abundances of foraminifera to low pH,
currents and waves, and turbid conditions, but mentioned that substratum type did not
have much influence on the distribution or abundance of foraminifera or ostracoda.
In a 12-month ecological study of Roanoke Sound, Croatan Sound, and Stumpy
Point Bay in northern Pamlico Sound, LeFurgey (1976) documented the living and dead
occurrence of foraminifera along dredged channels as part of an environmental impact
study of the effects of dredging on the benthic environment (see Schwartz, 1976, for a
more comprehensive ecological assessment). LeFurgey (1976) concluded that lower
Roanoke Sound had a distinctly different living population, dominated by Miliammina
fusca and Elphidium selseyense (E. excavatum of this study) from upper Roanoke Sound,
27
Croatan Sound, and Stumpy Point (northern Pamlico Sound), which was dominated by
Miliammina fusca and Ammobaculites crassus.
A comprehensive analysis of 86 sites was conducted on the continental shelf of
North Carolina by Schnitker (1971). He determined that two distinctly different faunas
exist north and south of Cape Hatteras. The northern fauna is similar to those described
by Parker (1948) from the coast of Maryland to Cape Cod and the southern fauna is
similar to those found from Cape Lookout to Florida (Wilcoxon, 1964) and from the
northeastern Gulf of Mexico (Parker, 1954). Schnitker (1971) noted that total number of
both benthic and planktonic forms increases with increasing depth and that diversity is
highest on the shelf south of Cape Hatteras. He recognized three distinct faunas for the
shelf north of Cape Hatteras, a nearshore fauna defined by >50% abundance ofElphidium
clavatum (E. excavatum of this study), and central shelf and shelf edge faunas defined by
lesser abundances of E. clavatum and increasing abundances of other subsidiary species.
Workman (1981) studied the foraminiferal surface distributions and down-core
occurrence from the inner nearshore of the Hatteras Embayment off Nags Head and in
southern Onslow Bay off Wilmington. His work echoed Schnitker’s (1971) conclusion
that two distinct faunas exist north and south of Cape Hatteras due to the influence of
different water masses. Workman (1981) characterized the foraminiferal assemblage off
Nags Head as being dominated by species of Elphidium-, while the assemblage in Onslow
Bay was characterized by species of Quinqueloculina. He concluded currents along the
substrate influenced assemblages by winnowing away the most easily transportable
28
foraminifera and that foraminifera from cores can be used to differentiate modem and
relict units.
To the north and south of North Carolina, numerous studies on the ecology and
distribution of foraminifera in various marginal marine environments have been
investigated. Just to the north in Chesapeake Bay, Virginia, Nichols and Norton (1969)
studied the populations of benthic foraminifera in the James River estuary (southern
Virginia), where they described two major faunas, an arenaceous Ammobaculites fauna
characteristic of the low brackish (0.5-14 salinity) inner estuarine fauna and a calcareous
Elphidium fauna of the higher brackish (>14 salinity) outer estuary. They note that the
boundary between these two faunas was quite distinct, occurring at an isohaline of 14 and
distributions within the estuary vary with seasonal changes in river inflow and salinity.
Ellison and Nichols (1970) studied foraminiferal distributions in the
Rappahannock River estuary in central Virginia. Their study showed two dominant
foraminiferal assemblages that characterize the estuary, influenced in part by salinity. A
basin biofacies in the outer part of the estuary was dominated by Elphidium clavatum
variants. A shoal biofacies, dominated hy Ammobaculites crassus, characterized the
inner part of the estuary, on shoals and along tributaries. The separation of these two
facies occurred along the 15 isohaline, which fluctuated with river inflow and estuarine
mixing.
Along the Atlantic coast of the Delmarva Peninsula, Woo (1992), Culver et al.
(1996) and Woo et al. (1997) studied foraminiferal distributions in a barrier island
lagoonal system. Woo et al. (1997) found that seven habitat zones were distinguishable
29
using the living population. Culver et al. (1996) found that only four major environments
were distinguishable by using the total assemblage (living + dead). The seven habitat
zones recognized by Woo et al. (1997) were: (1) brackish environment, (2) fringing
marsh, (3) valley marsh and tidal channel margin, (4) inner and mid-lagoon
environments, (5) washover fan, (6) outer lagoon, and (7) shoreface delta shoals. Using
the total assemblage, Culver et al. (1996) defined (1) brackish marsh / channel, (2)
lagoonal tidal flats, (3) lagoonal marshes / washover fans, and (4) channels / inlets /
shoreface.
In the Hudson River estuary of New York, Weiss (1976) studied the pattern of
foraminiferal distributions as a function of salinity throughout a 14-month study. He
recognized three salinity dependent assemblages, based on 13 genera and 17 species that
fluctuated within the estuary with the seasonal movement of salt water: (1)
Ammobaculites assemblage, characteristic of waters with salinities from 1 to no more
than 16; (2) Ammonia assemblage, characteristic of salinities averaging 20, (3) Elphidium
assemblage, found mostly in waters with salinity above 14. Weiss’s study had striking
similarities with those of Grossman and Benson (1967), Nichols and Norton (1969), and
Ellison and Nichols (1970), which found Ammobaculites to occur within the same
salinity range, 0.5 to 14. Weiss (1976) also found thdd Ammonia characterized areas
where salinities had the greatest variation and sharpest salinity gradients, results similar
to those by Nieves (1957) in the Lower New York Bay, Parker (1952b) in northern Long
Island Sound, and Grossman and Benson (1967) in Pamlico Sound. The Elphidium fauna
characteristic of Weiss (1976) study has also been recognized by other work along the
30
New York Bight (Ronai, 1955; Nieves, 1957) and in Long Island Sound (Buzas, 1965;
Thomas et ah, 2000).
Further to the south. Buzas and Severin (1982) studied foraminiferal densities and
distributions in the back-barrier lagoonal system of the Indian River along the east-central
coast of Florida during the months of February (1975), March (1975), April (1976), June
(1975), September (1977), and December (1975). They found that foraminiferal densities
vary considerably from station to station and month to month, but densities generally
increase to the south. Foraminiferal diversity reached its highest values at the three inlets
that connect the southern half of the estuary to the Atlantic Ocean. Canonical variate
analysis of the 15 most abundant species showed that all three inlets and one other station
(Flaulover) were distinct from the other areas. However, the inlets did not form a
homogeneous group; each inlet was distinct from the other.
Foraminiferal distribution patterns were first studied in the salt marshes of North
America by Phleger and Walton (1950). It was not until Phleger’s (1965) work in
Galveston Bay, Texas that salt marsh foraminifera were known to be vertically zoned.
Since then, marsh foraminiferal distributions have been the subject of much intensive
study for use in sea-level reconstruction (e.g., Scott, 1977; Scott and Medioli, 1980a;
Scott et al., 1991; Gayes et al., 1992; Collins, 1996; Horton et al., 1999; Hippensteel et
al., 2000; Spencer, 2000), paleoenvironment recognition, and ecological monitoring.
In the marshes of the Rappahannock estuary Ellison and Nichols (1970) found
two biofacies that characterized the marshes, an outer biofacies characterized by higher
salinities and Miliammina fusca and an inner biofacies characterized by less brackish
31
water and Ammoastuta salsa (Ammoastuta inepta of this study). Their results showed
that the total assemblage (largely dead) resembled the living population, exeept in local
areas where test redistribution is evident.
Scott and Medioli (1980a) made a comprehensive evaluation of salt marsh
foraminiferal zonations around Nova Scotia. Their study concluded that marsh
foraminifera were distributed in relation to their position in the tidal cycle and that these
zonations were useful in the determination of past sea levels. The most important of
these faunal zones is zone 1 A, indicative of the uppermost portion of the high marsh
(highest high water, HHW). The zone has an average vertical elevation difference of 10
cm and is marked by a monospecific assemblage of Trochammina macrescens
{Jadammina macrescens in this study). Faunal zone I B spans the lower portion of the
high marsh into the middle marsh and has an assemblage of Trochammina macrescens
and Tiphotrocha comprimata. Faunal zones 11 A and II B split the lower marsh with 11 A
extending into the lower middle marsh and II B extending the majority of the low marsh
into the upper limits of the estuarine zone. Faunal zone II A was composed of
Trochammina inflata and Miliamminafusca, while their lower marsh assemblage (II B)
was very similar to the estuarine assemblage, composed ofMiliammina fusca, Ammotium
salsum, and Cribrononion umbilicatulum, suggesting the lower marsh species were
characteristic of the estuary but have their upper limit in the marsh.
In South Carolina, Collins (1996) studied the vertical zonation of marsh
foraminifera with respect to sea level. He found that foraminifera were living to a depth
of 20 cm, but had generally little affect on the fossil assemblage. Preservation of
32
agglutinated species was determined to be very poor, due probably to bioturbation. His
investigation showed that foraminiferal zonations varied among the three study areas, but
were best developed at North Inlet. Zonations were not as clearly defined in the other
two areas, probably a result of development (Murrells Inlet) or high river discharge
(Santee Delta). Collins (1996) and Collins et al. (1999) also used marsh foraminiferal
assemblages to help define a sea level curve for sediments collected in vibracores from
Murrells Inlet, where a 2 m rise (between 5000 yBP and 4300 yBP) and a 2 m fall
(between 4300 yBP and 3600 yBP) of sea level were recognized.
Most recently, Spencer (2000) confirmed the presence of Scott and Medioli’s
( 1980a) three-zone subdivision of a salt-marsh on the southern Delmarva Peninsula. His
study noted that undetermined variables caused slight variation in fauna per zone, but for
the most part the assemblages remain very similar.
Current work being undertaken on the northern portion of the Outer Banks, North
Carolina by Horton and Culver (submitted) is characterizing the vertical zonation of
marsh foraminifera in back-barrier fringing marshes around Oregon Inlet, Currituck
Sound, and Pea Island. Culver and Horton (submitted) are also investigating the depths
that foraminifera live in salt-marsh along the same transects.
All of these studies show that the marginal marine environment is complex and
variations from region to region in distributions of species and environmental factors
have an influence on the distribution and number of foraminiferal assemblages that
characterize each study. All the more, these studies underscore the need for detailed
studies such as this one in the AES.
33
2.3 Paleoenvíronmental applications and taphonomy
Foraminifera are a highly used tool for paleoenvíronmental reconstruction, which
relies heavily on understanding how modem assemblages transfer to the fossil
assemblage and the changes, if any that occur during this process. But, foraminifera are
affected by a number of surficial and infaunal taphonomic processes, whether while
living or postmortem (Murray, 1973; Murray et ah, 1982; Goldstein and Watkins, 1995;
Martin, 1999; Goldstein and Watkins, 1999; Murray and Alve, 1999a, b; Hippensteel et
ah, 2000; Murray, 2001; Scott et al., 2001). These have a significant affect on the
distribution of foraminiferal populations and assemblages and their fossil representatives.
Martin (1999) describes the surface layer, which ranges in thickness from a few
centimeters to as much as a meter, as the Taphonomically Active Zone (TAZ) where the
“sediment acts as a low pass filter, primarily through bioturbation and dissolution, that
damps high frequency signals before their incorporation into the historical record.”
Surficial taphonomic processes such as physical transport by currents (Murray et
ah, 1982; Culver, 1980) and CaCOs dissolution (Murray and Alve, 1999a, b) are active in
marginal marine environments imparting a significant impact on the living and dead
assemblages. Culver (1980) summarized work in the Bristol Channel and the Severn
estuary on the significance of benthic foraminiferal test transport as pseudoplankton in
interpreting sediment transport in large embayments. Murray et al. (1982) have shown
that tidal currents and storm waves have sufficient energy to export foraminifera from
one area to another. They suggest suspended transport of tests is more widespread than is
generally recognized.
34
In interpreting the fossil assemblage some debate has surrounded which
assemblage of modem foraminifera to use, the living, dead or total assemblage, or a
combination thereof. Buzas (1968) viewed the living population as “a single frame of a
motion picture,” and to study the living population only one would have to do detailed
observations over a long period of time. However, Murray (1973) likened the use of the
total assemblage to that of using “graveyard residents in population statistics on humans.”
He added that the living population records the interplay of the fauna and the
environment, while the dead assemblage reflects changes in the living population
together with postmortem changes integrated over short- and long-term periods.
Albani and Johnston (1975) suggested that the total population was an integration
of all living populations and reflected the temporal and spatial variability of living
populations. Thus, they reasoned that the total assemblage was more reliable. Hence,
using the total assemblage would allow only a one-time sampling instead of detailed
seasonal studies. However, with a lack of conclusive data for either case, Scott and
Medioli (1980b) reasoned a detailed treatment of the subject was in order. They
summarized much of the previous work and conducted a long-term seasonal study of the
total assemblages along with the associated fluctuations in the living population in a
Nova Scotia salt-marsh.
Scott and Medioli’s (1980b) data showed great fluctuations in the percentages and
total numbers of the living populations, whereas only the total numbers fluctuated in the
total assemblage. Scott and Medioli (1980b) concluded that in marginal marine areas, if
the living population alone is considered then the assemblage patterns do not represent
35
the prevailing environmental conditions, but present external environmental factors, such
as meteorological inputs (e.g., temperature and rainfall).
However, recent work by Murray and Alve (1999a, b), Hippensteel et al. (2000),
and Martin et al. (2002) in marginal marine environments argues that in order to make
correct paleoenvironmental interpretations both the living and dead assemblages must be
compared in order to understand the taphonomic processes that result in the historic
record. Each of these workers concluded that use of the total assemblage does not allow
for accurate assessments and in the words of Murray and Alve (1999b), “would give
misrepresentative and misleading results.”
In order to facilitate an understanding of taphonomic processes at work in the
AES that result in the historic record, both the living and dead assemblages were studied.
The study of the living population generally shows where species were living and any
taphonomic processes affecting the population (e.g., dissolution and mechanical
destruction of tests). Study of the living population also allows for an understanding of
the depth to which species were living in the sediment (in select cores) in order to assess
mixing of the historic record with the living population. On the other hand, use of the
dead assemblages allow for comparison of several factors to assess the presence or
absence of taphonomic processes. Differences in species composition between dead
assemblages and living populations indicate several possible taphonomic processes such
as post mortem transport, dissolution, and mechanical destruction. Comparison ofboth
assemblages infaunally helps to identify modification of the historic record by
36
incorporation of younger and possibly different assemblages, as well as loss of species by
dissolution and mechanical destruction.
2.4 Radionuclide analysis of sediment accumulation
The study of sediment accumulation rates in lakes, peat pools, estuaries, bays,
rivers, sounds, and continental shelves using short-lived natural radionuclide tracers, such
as Pb and Cs, has increased over recent decades since its first use was pioneered by
Goldberg (1963). Goldberg (1963) used ^'^Pb as a dating methodology for glacial ice
and the first application of his method to sediments was by Krishnaswani et al. (1971) on
lake sediments and next, Koide et al. (1972) on marine sediments. Radionuclide tracers
have become very popular for determining sediment budgets for scheduling dredging
(Jetter, 2000), understanding how sedimentary strata form (McKee et al., 1983),
identifying the calendar dates of the onset of industrial pollution (Jetter, 2000), and in the
determination of sediment transport and deposition dynamics (Ravichandran et ah, 1995;
Dellapenna et al., 1998; Feng et al., 1999). Assessing the accumulation rates of sediment
in the study area is crucial to determining the sediment dynamics, as well as providing a
geochronology for analysis of changing environmental conditions in the water bodies
based on foraminiferal fossil assemblages in short cores.
Four common tracers being used, depending on the spatial and temporal scale of
investigation, are ^'*^Pb (half-life 22.3 years), '^’Cs (half-life 30.1 years), ^^"*Th (half-life
24.1 days), and ^Be (half-life 53.3 days). ^'°Pb and '^’Cs are the principle radionuclide
tracers utilized in this study. Pb is a daughter product in the U natural radioactive
37
family (Figure 2.1 ). The series starts with the decay of in soils (Figure 2.2), which
eventually decays to Rn by alpha particle decay and a fraction of the Rn is released
to the atmosphere where the Rn undergoes a series of short-lived radionuclide decays
to ^'^Pb (Oldfield and Appleby, 1984; Appleby and Oldfield, 1992). The ^'°Pb in the
atmosphere is then removed by precipitation and dry deposition onto land and water
bodies (i.e., lakes, sounds, rivers, etc.) where it is adsorbed readily onto sedimentary
particles in suspension and eventually incorporated with surface sediments. As surface
sediments are buried by successively younger sediments, a vertical profile of ^“^Pb
activity in the sediment column will show exponential decay with depth as a function of
the radioactive decay law, assuming steady state sedimentation and no mixing of
sediments. Therefore, the decay law can be used to date a sediment layer’s relative age
by using the sediment layer’s present Pb activity and by estimating the initial Pb
activity as long as the assumptions are accurate (Appleby and Oldfield, 1992). When the
decay law is applied universally without regard to changes in steady state and degree of
mixing, relative age dating is at best a maximum sedimentation rate.
The detonation of nuclear bombs in the atmosphere is the chief anthropogenic
producer of '^’Cs. Atmospheric deposition of '^^Cs began to increase in 1954 after the
first atmospheric test of a nuclear bomb began. From that point '^^Cs has remained at
higher levels in the atmosphere and varied yearly depending on the amount of tests. In
1963 '^^Cs reached its peak atmospheric level and since that time the concentration in the
atmosphere has decreased. The 1954 introduction and the 1963 peak of '^^Cs are crucial
for calibrating the Pb ages. However, Cs cannot be used independent of the Pb
38
Pa
Th
Ra
Rn
At
Po
Bi
Pb
Tl
hg
o More than one mg of the member is in equilibrium with one ton of uranium
o Main chain
Branching decays with percentage
? Branch member
o Stable terminal element
Figure 2.1. “*U natural radioactive family or 4n+2 family (from Adolf and Guillaumont, 1993).
Wash-out ot unsupported Pb from atrnosphere
unsupported from
catchment
Water
Sediments
Figure 2.2. Pathways by which ^'‘*Pb reaches the estuarine basin. (A) Particulate erosive input. (B) Direct
atmospheric fallout. (C) Indirect atmospheric input, (1) is not retained by particlutes in system and passes
quickly to the estuarine basin, (2) long residence time in the drainage basin before being delivered to the
estuarine basin. (D) Radon decay in the water column (from Oldfield and Appleby, 1984).
39
data due to the adverse affects of sediment resuspension (Christiansen et ah, 2002) and
cation exchange with pore water NH ^ in anoxic sediments (Johnson-Pyrtle and Scott,
2001) which can cause '^’Cs remobilization, altering the activity profile in the sediment
column. Other fallout radionuclide tracers like are very helpful in assisting ^'"^Pb
profile interpretation (Nie et al., 2001), but are not used in this study due to methodology
limitations.
There are three models by which the geochronology of sediments can be
calculated: Constant Flux-Constant Supply (CF-CS); Constant Rate of Supply (CRS); and
Constant Initial Concentration (CIC). All possess differing assumptions to account for
different environmental variables. Appleby and Oldfield (1992) give a detailed treatment
for each model. The “simple” model or CF-CS model was utilized in this study. It
assumes a constant flux of ^'°Pb and a constant sedimentation rate. It can be used when
the excess ^’‘^Pb activity profile is linear when plotted logarithmically versus a linear
depth profile. Accumulation rates can be calculated using,
A. = Aoe'‘ [2.1]
where Aj represents the excess ^'°Pb activity at a specific interval (i) at time (t), Aq
represents the sediment-water interface excess ^'*^Pb activity, and A. is the decay constant
(0.03114 yr "'). The sedimentation rate is calculated by dividing the decay constant X by
the slope of the best fit line for the profile.
As previously discussed, estuaries are very dynamic environments and vary in
their physical, chemical, and biological characteristics depending on the dominant
processes at work in each. Processes like physical mixing of sediments by bioturbation
40
and erosion/resuspension, as well as sediment focusing vary in their degree of importance
for each estuary. Sedimentation rates and sea-bed processes have been studied for
analogous estuaries along Chesapeake Bay (Brush, 1984; Oldfield et al., 1989;
Dellapenna et al., 1998; Dellapenna et al., 2003) and to the south of the AES in the
embayed estuaries of Pamlico Sound (Wells and Kim, 1989; Benninger and Wells, 1993;
Giffm and Corbett, 2003). Their results will be discussed later when compared with the
results of the present study.
Brush (1984) studied pre- and post-European settlement sedimentation rates in the
embayed tributary estuaries of Chesapeake Bay. Brush recorded average rates of 0.30 cm
yr ' since European settlement, with pre-settlement rates of 0.14 cm yr “ ‘ suggesting the
dominant influence man has had on increased sediment yields to the rivers. Oldfield et
al. (1989) did not publish quantified sedimentation rates but instead discussed the use of
magnetic susceptibility and inventories of excess ^'‘^Pb activity in cores down the
Potomac River estuary to determine the sources of sediment (riverine or land derived).
Their study showed an increase upstream of excess ^'®Pb inventories, which positively
correlated with total sedimentation rates per core. Magnetic properties indicated a shift to
surface-soil-derived sediment, increasing upstream, but with no such shifts apparent at
the mouth of the estuary, thus indicating that surface soil erosion was a dominant supplier
of excess ^'^Pb to the upper- and mid-estuary. Dellapenna et al. (1998) contrasted the
lower Chesapeake Bay with the York River estuary, the first being biologically
dominated and the latter being physically dominated. Their investigation found similar
41
accumulation rates as Brush (1984) < 0.2 cm yr ' at the York River site and <0.1 cm yr''
at the lower Bay site.
Wells and Kim (1989) using purely sedimentalogical data, hypothesized that the
estuarine sediments of the Neuse River, North Carolina went through repeated processes
of sedimentation, resuspension and transport down estuary by high river discharge or
wind events which would potentially deposit those sediments into the larger Pamlico
Sound Basin. Based on preliminary data from radionuclide tracers, Benninger (1990)
suggested that this process is occurring and that the estuarine sediments of the Neuse
River are remobilized and transferred down estuary where they accumulate at rates < 0.6
cm yr '. Benninger and Wells (1993) further concluded that episodic, unidirectional
transport of estuarine sediments was the chief mechanism for moving these sediments
down the Neuse River estuary into the Pamlico Sound, where there was minor loss
through the inlets to the oceans.
The particle reactive nature of the radionuclide tracers has caused some debate as
to the physical and chemical processes (variables like grain-size, organic content, salinity
and cation exchange in anoxic sediments) that could disrupt the adsorption process in
suspension or in situ, thus affecting accurate assessment of sedimentation rates
(Benninger and Wells, 1993; He and Walling, 1996; Ligero et al., 2001; Johnson-Pyrtle
and Scott, 2001). Benninger and Wells’s (1993) excess ^’°Pb and '^’Cs data from 10
cores along a substantial salinity gradient (l%o near its head to ~25%o at its mouth) in the
Neuse River estuary show no apparent pattern of change in downstream activities as a
function of salinity. Surface sediments are predominantly organic-rich mud, which
42
eliminate salinity as a potential variable for selective adsorption. He and Walling (1996)
discuss the effects of grain size on mineral soils and sediments, finding that radionuclides
preferentially adsorb onto finer particles, as was shown by Ligero et al. (2001). Also, the
latter investigation positively correlated '^^Cs activity and organic content. Johnson-
Pyrtle and Scott (2001) discussed the potential for cation exchange with pore water NH ¡
in anoxic sediments as a cause of '^^Cs remobilization in the sediment column.
However, no such studies exist previous to this one in the AES that address the
modem sediment dynamics. Thus, due to the volume of cores and the temporal limitation
(no repeated sampling at established stations), it was more advantageous to produce a
general geochronology via the CF-CS model and present the broader scope of tracer
patterns in the AES using tracer profiles and inventories to understand sediment
dynamics.
CHAPTER 3
METHODOLOGY
3.1 Field Methods
Benthic sediment sampling and short-coring at 53 stations in the AES (see Figure 1.3)
commenced on June 26, 2001 and ended July 6, 2001 with two additional short cores
retrieved on March 12, 2002. These station locations ranged from the fringing marshes to
estuarine basins to the shoreface. At most stations salinity and temperature were measured at
the top and bottom of the water column and three short cores (7.62 cm diameter) were
collected for radionuclide age dating, micropaleontological work and x-ray analysis. The
cores were collected using a push-coring device equipped with a one-way flow valve
allowing water to move upward as the core tube was inserted into the sediment; the valve
provides suction to avoid loss of core upon extraction. Onboard the boat, the first two cores
collected at each site were extruded and subsampled. The core for radionuclide tracer studies
was subsampled at 2 cm intervals to 4 cm and 3 cm intervals below 4 cm. The core for
micropaleontological work was subsampled every centimeter down to 4 cm, every 2 cm to 10
cm, and every 3 cm below 10 cm. Foraminiferal subsamples (50 cm^) were stored
immediately in 4 oz. nalgene bottles in a 5% buffered formalin solution to prevent the decay
of foraminiferal protoplasm. The third short core was x-rayed to elucidate the sediment
structure and content (e.g., roots, shells, burrows, sand, mud, etc.) of the core. It is important
to determine the extent of bioturbation, which can affect precision and resolution of Pb and
44
137Cs analyses, and to identify sedimentary features that may be important to interpretation of
the geochronology of the core.
If the substrate tjq^e was such that a core could not be taken (e.g., coarse sand), a grab
sample was collected using a Ponar grab sampler. Sediment samples were collected from the
top 1 cm of sediment and stored as described above. The foraminiferal surface study used
one sample per site, either the top centimeter of a short core or the top centimeter of a grab
sample.
3.2 Laboratory Methods
3.2.1 Foraminiferal Analysis
Forty-nine of the 53 stations were selected for foraminiferal analysis; each 50 cm^
sample was washed over 710 pm and 63 pm sieves to remove formalin, silt, clay, and coarse
particulates (marsh detritus or coarse sand, gravel, or shells). The >710 pm coarse residue
was described and bagged, and stored for future reference. The sieves were washed with
methylene blue between samples to stain any particles remaining in the sieves and thus to
identify any contaminant particles. All muddy samples were soaked for two hours in a dilute
sodium metaphosphate (NA(P03)6) solution to disaggregate the mud particles before being
washed over the sieves. The residue on the 63pm sieve was stained with rose Bengal
(Walton, 1952) for six to eight hours, while preserved in isopropyl alcohol. The sample was
then washed over the 63 pm sieve again to remove any excess stain. The stained residue
remaining on the 63 pm sieve was returned to a bottle and preserved with isopropyl alcohol.
In sand-rich samples foraminifera were concentrated by using a calibrated sodium
45
polytungstate solution (density s 2.34 g/ml) to separate the sand from the foraminifera
(Munsterman and Kerstholt, 1996).
Samples were spread on a gridded picking tray and 300 specimens were picked using
a random numbers table to select grid squares. In order to obtain statistically valid values for
species proportions, 300 to 400 specimens are ideal to account for most species present in a
sample (Buzas, 1990). If a sample was very large it was split into smaller aliquots using a
microsplitter until 300 specimens could be easily picked. The specimens were placed onto a
60-square micropaleontological slide covered with a thin layer of gum tragacanth (water
soluble glue) to gently affix the foraminifera to the slide. Specimens were separated into
similar morphologic groupings, and proportions of living and dead were calculated. Living
specimens were assessed by wetting the specimen on the slide. Specimens containing one or
more chambers of deep pink-stained protoplasm (rose Bengal) were deemed to be live at time
of collection. Identification of specimens was made through comparison with the published
literature and through comparison with type specimens at the National Museum ofNatural
History, Smithsonian Institution, Washington, D.C. After identifications were validated,
final counts of living and dead for each species were made.
After taxa were identified, representative specimens of each species were picked for
SEM imaging. SEM imaging was performed on a Philips 500 at the Department of Biology,
East Carolina University. Each specimen was transferred to an SEM stub covered with
double sided adhesive tape using a 000 brush. The stub was sputter coated with a gold
palladium alloy using a Polaron El 500 Auto Coating unit.
46
3.2.2 Radionuclide Analysis
All sediment samples were analyzed for three radionuclide tracers, ^'°Pb (46 keV),
Cs (661 keV), and Ra. Samples were first processed by placing the sediment stored in
bags into plastic weigh boats and drying the samples for up to two days at 60°C. Dried
samples were crushed into a fine powder using a mortar and pestle (excluding sand-rich
samples). Samples were packed into one of two geometries, an aluminum tin (volume) or a
plastic vial (volume) and sealed for 30 days to allow in-growth of ^^^Rn. Sample sizes
ranged from approximately 5 to 50 g depending on geometry and sediment type. Sealed
samples were then analyzed for 12 to 24 hours by direct gamma counting using one of two
low-background, high-efficiency, high-purity Germanium detectors (Coaxial- and Well-type)
coupled with a multi-channel analyzer. Detectors were calibrated using several natural
matrix standards (IAEA-300, IAEA-312, and IAEA-314) at each energy level of interest in
the standard counting geometry of the associated detector. ^'°Pb activities were corrected for
self-absorption using a direct transmission method (Cutshall et al., 1983; Cable et al., 2001).
In short, direct transmission measurements are made on an empty container using high
activity low-energy-emitting radionuclides ( Pb, Ra, U). Standard equations for the
ratio between attenuated (sample) and unattenuated (empty container) counts may then be
applied to correct for absorption. Excess ^'‘^Pb was calculated as the difference of total ^’‘’Pb
(46 keV) and ^^^Ra, determined indirectly by counting gamma emissions of its grand
daughter ^’^Pb (295 and 351 keV) and ^'^Bi (609 keV).
Porosity of sediment intervals was measured by filling a pre-weighed vial of known
volume with sediment, weighing it on a top-loading balance, drying it at 60°C for one to two
47
days and reweighing. The weight of water in the sediment was divided by the dry weight of
the sediment to calculate the porosity. Dry bulk density was calculated according to (1 -
p)*2.4, where p is porosity and 2.4 is the assumed average density of the sediment
(Benninger and Wells, 1993). Sedimentation rates were calculated by the CF-CS model
(Appleby and Oldfield, 1992) using a linear regression analysis of the natural log of the
excess ^'°Pb activity verses depth. Accumulation rates were calculated by using a linear
regression analysis of the natural log of the excess Pb activity verses mass accumulation.
3.3 Foraminiferal Data
3.3.1 Cluster analysis
Cluster analysis, a pattern recognition method (Mello and Buzas, 1968), was
employed in order to delineate groups (biofacies) in the surficial foraminiferal data. Cluster
analyses on surficial and down-core samples of live and dead data sets were performed using
SYSTAT. All species found live were included in the live cluster analysis. Only, the most
abundant foraminiferal species in the dead assemblage were used for clustering in order to
filter out the noise of rare species. The most abundant foraminifera were defined as those
species that comprised 5% or more of the assemblage in any one sample. Prior to analysis,
proportions (%) for each species were transformed according to 2 arc sin Vp/, where pi is the
proportion of the iih foraminiferal species within the sample (Buzas, 1979). The hierarchical
clustering method (Davis, 1986) was chosen to cluster the data and was performed using
SYSTAT version 10.0. This method produces hierarchical clusters that are displayed as a
tree dendrogram. The software begins computing the dendrogram by initially considering
48
each object, whether case or variable (R-mode or Q-mode) as a separate cluster. The
computations continue stepwise by joining the two "closest" objects as a cluster, then joining
either an object with another object, a cluster, or a cluster with another cluster until one
cluster encompassing all objects is formed (SYSTAT, 2001). All clustering was performed
by treating the samples as variables, which is described by Buzas (1979) as Q-mode
clustering. Ward’s linkage was used in defining distances between pairs of objects in
different clusters. This method averages pairs with adjustments for covariance, to determine
the spacing of the clusters. Euclidean distance measures the similarity between matching
pairs of objects on a scale of zero to n.
3.3.2 Species Diversity and Equitability
Numbers of benthic foraminiferal species per sample are known to vary depending on
latitude, increasing toward the equatorial region, and distance from shore, increasing with
depth (Buzas and Gibson, 1969; Buzas, 1972; Gibson and Buzas, 1973; Buzas et al., 2002).
Species diversity has been related to the number of species present in a sample, but this fails
to take into account the relative abundance of each species' distribution within the sample.
Thus, the numbers of species and their proportions are used to define diversity. The most
commonly used diversity measure that takes into account these variables is the Shannon-
Wiener information function (Shannon, 1948; Gibson and Buzas, 1973; Hayek and Buzas,
1997). The equation for the information function H(S) is,
H(S) = -XP'ln(pO (3.1)
/ = 1
49
where S is the number of species and pi is the proportion of the ith species in the assemblage
(Buzas and Gibson, 1969; Gibson and Buzas, 1973). Species diversity, H(S), measures the
level of uncertainty that a specimen picked from a sample will be correctly predicted to be a
given species and is a reflection of the amount of information contained in the sample
(Hayek and Buzas, 1997). Thus, if a sample is composed of one dominant species with other
species in minor proportions, the value of H(S) will be low, because the uncertainty is low
and the probability is high that the dominant species will be picked. Thus, the sample
possesses little information and has a low H(S) value (Hayek and Buzas, 1997). On the
contrary, if specimens in the sample are evenly distributed among species, the uncertainty
would be at its highest and the probability its lowest, thus, the H(S) value would be the
highest possible for a given number of species. Thus, the greatest value of H(S) for any
sample is equal to In of S (Gibson and Buzas, 1973; Hayek and Buzas, 1997).
In order to measure and express the distribution of species proportions in a sample.
Buzas and Gibson (1969) devised a measure of equitability (evenness, dominance, etc.). The
formula for equitability, E, is
E = e“'^VS (3.2)
where e is the base of the natural logarithms, H(S) is the information function, and S is the
number of species in a sample (Buzas and Gibson, 1969). The value that results from e, the
base of the natural logarithms, being raised to the power H(S), is a measure of the equivalent
number of equally distributed species, e^*^^= S. Hence, the ratio e^*^V S measures the
equitability that ranges from 0 to 1, where a ratio = 1 is a perfectly even distribution (Buzas
and Gibson, 1969) and a value of 0 represents a monospecific assemblage.
50
3.3.2 Biofacíes Fidelity and Constancy
Once biofacies have been recognized through cluster analysis, biofacies fidelity (BF)
and constancy (C) can be calculated for each species per biofacies to define which species
are responsible for the bioassociation (Hazel, 1977). Constancy is calculated as a percent by
dividing the number of samples within a biofacies in which a species occurs, occurrence (O),
by the number of samples in that biofacies. This percentage is then used to calculate the
biofacies fidelity by the following formula,
BF,,,= ^xlO (3.3)
i=]
where BFy., represents the ith species (/') in a biofacies (i), and P¡ represents the percentage
occurrence (constancy) of that species for which the BF is being calculated (Hazel, 1977).
Thus, the BF for a species and its biofacies is calculated by dividing a species’ constancy by
the sum of that species’ constancy in all other biofacies (Hazel, 1977). Calculated values for
BF and C were expressed as a number between one and ten, and values were rounded to the
nearest whole number for ease of comparison and to reflect the accuraey of the method
(Hazel, 1977). Calculations for biofacies fidelity and constancy were done using
spreadsheets created in Excel 2000.
CHAPTER 4
RESULTS AND INTERPRETATIONS
4.1 Environmental Conditions
Benthic sediment sampling and short coring included 53 stations (see Figure 1.3,
Table 1.1). Measurements of salinity, temperature, and dissolved oxygen at the surface
and bottom of the water column are presented in Table 4.1. These measurements were
not assumed to reflect annual values, because it is known (Bowden and Hobie, 1977;
Copeland et al., 1983; Giese et al., 1985; Wells and Kim, 1989) that these variables vary
considerably through the seasons as freshwater inflow, precipitation, evaporation, winds,
and temperatures change (see Figures 1.9-1.13).
Salinities in the AES fluctuate seasonally, resulting from the interplay between
changes in freshwater inflow and saltwater intrusion from Oregon Inlet and the more
saline Pamlico Sound. Recorded surface salinities (Table 4.1) ranged from 0.6
(PASOISI) to 35.0 (BEA01S1-S3). Surface and bottom salinities on the ebb delta
(EBBOISI) were 30.0 and 28.6, and 28.2 and 24.8 on the inner shelf (OFFOISI)
signifying measurable dilution of normal marine water with brackish sound water. The
highest back-barrier surface salinity (31.6) was recorded at the flood-tide delta of Oregon
Inlet (INSOISI). Salinities in the sounds north of Oregon Inlet did not exceed 15.0.
Salinity variations between top and bottom waters in the AES were generally minor and
increased slightly with depth at most stations. The largest variations (1.8 and 2.0) were
recorded in the central basin of Albemarle Sound (ALB01S3) and at the head of the
52
Table 4.1. Salinity, temperature, and dissolved oxygen measurements taken at
time of sampling.
Water Surface Bottom Surface Bottom Surface Bottom
Station Depth Salinity Salinity Temp. Temp. D.O. D.O.
(m) (PPO (PPt) rc) (“C) (%) (%)
BEAOISI 0.0 35.0 — 19.0 — — —
BEA01S2 0.0 35.0 — 21.0 — — —
BEA01S3 0.0 35.0 — 19.0 — — —
INSOISI 1.2 28.7 — 22.2 — — —
EBBOISI 2.4 30.0 28.6 23.2 23.7 — —
OFFOISI 9.3 28.2 24.8 21.5 17.3 — —
ALBOISI 5.2 — — — — — —
ALB01S2 5.5 2.7 3.0 27.1 26.1 100.0 93.0
ALBO1S3 5.8 2.0 3.8 26.3 26.5 95.0 86.9
ALB01S4 5.5 5.3 5.0 27.0 26.1 104.5 99.0
ALB01S5 3.4 3.8 4.3 27.8 26.8 99.5 100.0
ALB01S6 3.7 5.7 5.7 27.0 27.0 94.8 94.8
ALB01S8 1.8 6.2 — 28.3 — — 100.0
ALLOISI 2.7 3.4 2.9 28.2 26.4 98.3 93.5
ALL01S2 4.3 3.8 4.2 28.8 26.6 99.0 99.0
ALLO 1 S3 2.1 3.9 — 27.2 — — 92.4
ALL01S4 1.8 4.6 — 28.5 — — 99.0
ALL01S5 3.4 3.9 — 26.7 — — —
EL02S1 2.4 ... — — — —
SL02S1 2.4 — — — — — —
PASOISI 2.4 0.6 2.6 29.6 28.3 — —
PAS01S2 3.7 3.1 3.5 31.1 27.4 — —
PASO1S3 4.0 3.9 3.8 30.1 28.1 — —
NOROISI 3.0 3.7 3.4 28.3 27.5 — 93.8
NOR01S2 2.7 4.5 4.7 28.5 28.0 100.0 —
CUROISI 0.9 5.1 — 28.4 — — —
CUR01S2 0.1 — — — — — —
CURO 1 S3 0.8 5.1 — 30.3 — — ...
CUR01S4 0.2 4.7 — 30.9 — 98.0 —
CUR01S5 1.5 4.0 — 30.0 — — —
CUR01S6 0.6 6.2 — 31.5 — — —
CUR01S7 2.1 5.4 5.2 30.1 29.0 — —
CUR01S8 2.1 5.3 5.5 30.3 29.6 — —
CUR01S9 0.0 5.3 — 30.2 — — —
CUROISIO 0.3 7.0 — 28.0 — — —
CROOISI 3.7 5.9 7.6 28.8 27.8 110.0 100.0
CRO01S2 3.0 9.0 — 28.4 — — —
CROO 1 S3 3.0 9.0 — 28.2 — — —
CRO01S4 0.0 7.6 ... 29.1 ... ... ...
53
Table 4.1. Continued.
Water Surface Bottom Surface Bottom Surface Bottom
Station Depth Salinity Salinity Temp. Temp. D.O. D.O.
(m) (PPt) (PPt) (deg.) (deg.) (%) (%)
CRO01S6 1.8 8 — 28.7 — — —
CRO01S7 1.8 7.8 — 294 — ... —
ROAOISI 2.4 10 10 29.2 29.2 ... —
ROA01S2 0.6 11.4 — 27.3 — — ...
ROA01S4 0.6 10 — — 27.4 — —
ROA01S5 0.0 9.8 — 27.2 — — —
ROA01S7 0.1 — — — — — —
ROA01S9 0.0 9.0 — 28.0 — — —
PAM01S2 0.6 13.5 — 26.6 — — —
PAM01S5 0.5 14.0 — 22.0 — — —
PAM01S6 0.1 13.0 — 27.0 — — —
PAM01S7 0.1 15.0 — 29.0 — — —
PAM01S8 0.1 15.0 — 29.0 — — —
PAM01S9 0.1 15.0 — 30.0 — ... ...
54
Pasquotank River (PASOl S1 ). Bottom salinities in Albemarle Sound ranged from 3.0 at
ALB01S2 to 6.2 at ALB01S8.
Dissolved oxygen measurements (Table 4.1) were only taken in Albemarle
Sound, Alligator River, North River, and at one site in Croatan Sound. For the most part,
dissolved oxygen was high, reaching its lowest (86.9% saturation at bottom) at ALBO 1 S3
to its highest (110% at surface) at CROOl SI. Bowden and Hobbie (1977) recorded
similar values and noted that dissolved oxygen was generally consistent within the AES.
Water temperatures were highest at the surface, ranging from 26.3-31.1“ C, and decreased
with depth; variations between top and bottom averaged 1.2” C for the entire AES.
Sediment data was acquired for the 27 short cores from Letrick (2003).
Sediments were divided into two fractions for this study, mud (< 63 pm, clay and silt)
and sand (> 63 pm) and expressed as a relative percent per sample (Appendix E).
Surface sediment grain-size trends show a strong relationship with bathymetry as first
shown by Pels (1967) (see Figure 1.8), thus confirming that depth and wave base play an
important role in the surficial arrangement of sediment in the AES. In general, the
sediments range from organic-rich mud (ORM) in the central basin and embayed
tributary channels to fine to medium sand on the perimeter platform, back-barrier, and
inlet shoals, and the foreshore and inner shelf.
4.2 Surface Distribution of Living Foraminifera - General Observations
Nineteen species (15 agglutinated, 4 calcareous) from 40 of the 49 stations
(Appendix A) characterized the living population. The 15 agglutinated taxa are found
55
living exclusively in the back-barrier estuarine environment. Of the four calcareous
species, three were limited to the estuarine environment surrounding the back-barrier side
of Oregon Inlet and the southern shores of Roanoke Island, Ammonia parkinsoniana.
Ammonia sp. (organic linings only), and Elphidium galvestonense.
The number of living individuals per 50 cm^ of sediment varied from one
(BEAOISI) to 6,624 (NOR01S2) specimens over the study area (Appendix A). Low live
specimen numbers corresponded with a variety of environments including stations near
freshwater inflow, shoals along the perimeter platform and adjacent back barrier system,
the ebb delta shoal, and the foreshore. Highest living specimen numbers were associated
with the central basins of the sounds and embayed tributary channels, and fringing marsh
areas in the central and eastern portions of the AES. Species abundance (expressed as
proportions of the living population) is given in Appendix B.
•5
Numbers of living species varied from one to seven per 50 cm sample (Appendix
B). Lowest numbers of species were generally at or near river mouths, embayed tributary
channel, perimeter platform shoals, sand-rich back-barrier shoals, and on the foreshore
and ebb delta. Highest numbers of species were in marshes and in adjacent estuarine
waters possessing a mixture of marsh and estuarine foraminifera. Calculations of species
diversity, H(S), and equitability, E, were not applied to the live data due to the low
numbers of specimens.
The 19 living species displayed four general groupings which corresponded to the
environments in which they were found. Seven species lived exclusively in the fringing
marsh environment, including associated runnels and algal-bounded sand flats
56
{Ammoastuta inepta, Arenoparrella mexicana, Haplophragmoides bonplandi,
indeterminate agglutinated unilocular species, Jadammina macrescens, Miliammina
petila, and Trochammina inflata). Seven species ranged between the estuarine basins and
fringing marsh environment {Ammobaculites crassus, Ammobaculites exiguas,
Ammobaculites subcatenulatus. Ammonia sp., Ammotium salsum, Miliammina fusca, and
Tiphotrocha comprimata). Four species were found living exclusively in the sounds and
nearshore back-barrier waters {Ammobaculites dilatatus. Ammonia parkinsoniana,
Elphidium galvestonense, and Reophax sp.). On the Atlantic Ocean side of the barrier
system, one species, Elphidium excavatum, was found living on the ebb delta (EBBOISI)
and the foreshore (BEAO1S1 ).
4.3 Surface Distribution of Dead Foraminifera - General Observations
Thirty-seven benthic foraminiferal taxa (28 agglutinated, 9 calcareous) were
recorded in the dead assemblages at 48 of 49 stations (Appendix C). Thirty-one species
were identified to the species level and four to the genus level. Indeterminate organic
linings were counted as a group. One of the 49 stations, CUROl S6, located on a
subaerial sand overwash fan, was barren of foraminifera and was not included in further
analysis.
Numbers of dead specimens per 50 cm^ per station varied from three on a back
barrier intertidal shoal (ROA01S9) to 261,669 (calculated) in a small tidal creek next to a
Juncus marsh (ROAOl S4) (Appendix C). In general, numbers per 50 cm^ were lowest
near freshwater inflow, on sandy perimeter platform shoals around the interior of the
57
AES, back-barrier shoals, inlet shoals (flood and ebb) and the shoreface where food is not
as prevalent as in muddier environments. Numbers per 50 cm^ increased from the shoals
to the central axis of the sounds and embayed tributaries. Specimen numbers were
highest in the fringing marshes and their adjacent nearshore flats and in the central basins
of some of the eastern sounds and embayed tributaries. Species abundance (expressed as
proportions of the dead assemblage) is given in Appendix D.
The numbers of dead species, S, varied from three to 16 species per sample
(Appendix D). Highest numbers of species were found in the fringing marsh (CUROl S2,
CUR01S4, CRO01S4, ROA01S5) and adjacent estuarine waters (ALLOISI, CRO01S3,
CRO01S6, CRO01S7, ROA01S7, ROA01S9, PAM01S5). The central basins of the
sounds and embayed tributary channels had moderate numbers of species, usually four to
seven. The perimeter platform and back-barrier shoals had similar numbers of species.
Species numbers were lowest in high energy environments such as the foreshore
(BEAOISI, BEA01S2, BEA01S3), ebb- and flood-tide delta shoals (EBBOISI,
INSOISI), and some back-barrier shoals and channels (ALB01S6, CRO01S7,
ROA01S2).
Species diversity, H(S), was calculated for the dead assemblages (Appendix D).
Low values of H(S) on the foreshore and delta shoals were due to dominance of one
species, Elphidium excavatum. This high dominance was likely due to the extreme stress
caused by waves and currents in these environments (Buzas and Gibson, 1969; Woo et
ah, 1997). Values of H(S) in the coastal barrier system ranged from 0.14 on the foreshore
(BEAOISI) to 2.31 in an eroding mnnel of a marsh (CUR01S4). Relatively low values
58
of H(S) occur at sandy environments like the foreshore (BEAOISI) and the ebb and
flood-tide deltas (EBBOl S1, FNSOlS1 ). The highest values of H(S) were in an intertidal
mud flat (PAMOl S5, 1.99), marsh mnnel (CROOl S4, 2.30), and fringing marsh
(ROA01S5, 1.76; CUR01S4, 2.31). These values result from high numbers of species
per sample (13, 14, 16, and 15, respectively) and the nearly even abundances of the
abundant species in the sample (e.g., Ammotium salsum, Miliammina fusca,
Ammobaculites crassus, and Trochammina inflata).
Values of species equitability, E, (Appendix D) were generally lowest on the
foreshore, shoreface, and ebb- and flood-tide delta shoals (BEAOISI, BEA01S2,
BEA01S3, EBBOISI, INSOISI) and in the estuarine central basin (ALB01S3, ALB01S4,
CUR01S7, CUR01S9, ROA01S4), the surrounding perimeter platform (ALB01S5,
ALL01S4), back-barrier shoals and nearshore flats (ALB01S8, CROOlS6, ROAOISI,
ROA01S7) and embayed tributary channels (ALL01S2, NOR01S2). This trend was
caused by the high dominance of one species among other rare species in the sample.
The highest values of E were from the fringing marshes (CUR01S2, CUROl S4,
ROA01S5), intertidal sand flats near fringing marshes (ROA01S9, PAMOl S8,
PAMOl S9) and the inner, more protected reaches of the estuary (ALBOISI, ALLOISI,
PASOl S1, NOROl S1 ). These values were largely the result of a few species occurring in
abundance with varying numbers of rare species present. For the most part values of
H(S) were affected by differences in equitability rather than changes in the number of
species.
59
4.4 Cluster Analysis of Surface Stations - Living Population
Cluster analysis was performed on transformed proportions data for the living
populations and included all living species due to the low total number of living
specimens. The dendrogram (Figure 4.1) produced by the cluster analysis is composed of
four, six, or nine nested groups. A plot of four groups produced the most ecologically
meaningful pattern (Figure 4.1, Table 4.2). These four groups are referred to below as
Biofacies and represent living populations of benthic foraminifera. Species diversity and
equitability were not calculated because the numbers of specimens were too low. The
low numbers of living specimens also makes the significance of the biofacies fidelity and
constancy values questionable. In discussion below, categories of average relative
abundance (where the average relative abundance represents the average of all relative
abundances of a species at each station within a biofacies) have been defined as: most
abundant (>50%), abundant (25 to 49%), common (5 to 24%), and rare (<5%).
Biofacies 1 (Figure 4.1,4.2, Table 4.2) is composed of 13 stations from a variety
of environments including the inner estuary (ALBOISI, PAS01S2, CUROISIO), fringing
marsh (CUR01S2, CUR01S4, CRO01S4, ROA01S4, ROA01S5), perimeter platform
shoal (ALLO 1 S3, ALL01S4, CRO01S7), back-barrier shoal (ROA01S2), and embayed
tributary channel (ALL01S5). The number of species varied from one to seven and
calculated number of specimens per 50 cm^ ranged from six (ROA01S2) to 3,888
(ROA01S5).
The average relative abundance of species within the biofacies (Table 4.3)
showed Miliammina fusca as the most abundant species while other estuarine species
60
crt
o 6
Biofacies Stations Z Z
ALLOISS 3
ALL0IS3 2
ALBOISI 2
ALL01S4 2
CUR0IS4 46
1 CUROISIO 15
ROA01S5 27
CROOIS7 16
ROA01S4 5
PAS01S2 16
CUR01S2 6
CRO01S4 17
ROAOIS2 6
2 EBBOISI 2BEAOISI 1
CUR01S9 1
ALB01S2 1
CUR01S5 12
PAM0IS9 173
CUROISI 20
NOR01S2 23
CUR01S7 8
PASOISI 4
3 NOROIS 1 3
CROOISI 22
ALB01S4 17
CRO01S3 12
PAM01S6 73
PAM01S8 267
PAM01S7 196
ALB0IS3 15
ALB0IS5 8
PAM01S5 174
ROA01S7 20
CROOIS2 5
PAM01S2 4
4 ALB0IS6 69
ALB01S8 73
ROAOISI 7
PASO! S3 1
0 12 3 6
Figure 4.1. Dendrogram produced by cluster analysis (Ward’s linkage, Euclidean distances) of
transformed proportions data for the living foraminifera.
61
Kilometers
• Biofacies 1
• Biofacies 2
• Biofacies 3
o Biofacies 4
o Sample Stations with
no living species
' ^
Figure 4.2. Map showing distribution of four biofacies identified by cluster analysis of all living
foraminiferal data.
62
Table 4.2. Stations were grouped into biofacies (B) through cluster analysis of the living populations
composed of all species. Interpretations for each biofacies, number of species (S), number of specimens
picked (N), and calculated number of specimens per 50 cm^ (n) are listed for each station.
B Interpreted environment(s) Stations S N n
1 Mixed marsh and ALL01S5 1 3 154
estuarine ALLO 1 S3 1 2 11
ALBOISI 1 2 64
ALL01S4 1 2 2
CUR01S4 5 46 1123
CUROISIO 3 15 15
ROA01S5 7 27 3888
CRO01S7 4 16 2248
ROA01S4 2 5 4114
PAS01S2 3 16 768
CUR01S2 2 6 57
CRO01S4 6 17 620
ROA01S2 4 6 6
Mean 3 il 1005
2 Nearshore marine EBBOISI 1 2 2
BEAOISI 1 1 1
Mean i 2 2
3 Estuarine CUR01S9 1 1 5760
ALB01S2 1 1 27
CUR01S5 1 12 768
PAM01S9 6 173 1703
CUROISI 2 20 1146
NOR01S2 2 23 6624
CUR01S7 2 8 2048
PASOISI 3 4 91
NOROISI 2 3 384
CROOISI 2 22 939
ALB01S4 2 17 2448
CROO 1 S3 2 12 307
PAM01S6 4 73 779
PAM01S8 5 267 316
PAM01S7 4 196 1307
ALBO1 S3 3 15 831
ALB01S5 3 8 180
PAM01S5 7 174 2610
Mean 3 51 1570
4 Estuarine shoals ROA01S7 3 20 210
CRO01S2 2 5 90
PAM01S2 2 4 4
Table 4.2. Continued.
B Interpreted environment Stations S N n
Cont. ALB01S6 2 69 1606
ALB01S8 4 73 142
ROAOISI 1 7 2520
PASO 1 S3 1 1 55
Mean 2 26 661
64
Table 4.3. Average relative abundance of species per biofacies for the living populations.
Values expressed as an average percent of all the samples in a given biofacies; the most
abundant values are in bold.
Biofacies Biofacies Biofacies Biofacies
Taxon 1 2 3 4
Ammoastuta inepta 2.7
Ammobaculites crassus 6.3 14.6 83.2
Ammobaculites dilatatus 1.3 0.1 0.2
Ammobaculites exiguas 0.4
Ammobaculites subcatenulatus 5.7 0.7 0.2
Ammonia parkinsoniana 1.6
Ammonia sp. (organic lining) 4.6 0.3
Ammotium salsum 7.5 75.7 15.0
Arenoparrella mexicana 1.6 100.0
Elphidium excavatum
Elphidium galvestonense 0.1
Haplophragmoides bonplandi 0.9
Jadammina macrescens 1.2
Miliammina fusca 65.9 4.8 1.4
Miliammina petila 1.4
Reophax sp. 0.1
Tiphotrocha comprimata 0.3 1.4
Trochammina inflata 0.6
Indeterminite aggl. unilocular sp. 0.3
65
were only rare to common. Because this biofacies includes stations from fringing
marshes, the majority of species with low average relative abundances were marsh
species. Biofacies fidelity (Table 4.4) also showed that M. fusca possessed the strongest
combination of constancy and biofacies fidelity values (9 and 7, respectively). The
highest biofacies fidelity values (10) for this biofacies were for marsh species such as
Ammoastuta inepta, Arenoparrella mexicana, Haplophragmoides bonplandi, Jadammina
macrescens, Miliammina petila, and Trochammina inflata, but these taxa have low
abundances and all have very low constancy values (1). This biofacies was interpreted to
represent a mixed marsh and estuarine environment. The chief grouping factor of this
biofacies was the dominant presence of M. fusca.
Biofacies 2 (Figure 4.1, 4.2, Table 4.2) is composed of two stations on the Oregon
Inlet ebb delta (EBBOl SI) and the barrier island foreshore (BEAOISI). These high-
energy environments were dominated by sand (> 99% sand). They were characterized by
low numbers of specimens with only one living species, Elphidium excavatum. Low
numbers of specimens in these environments have been attributed to the dynamic
substratum conditions in which the foraminifera must exist (Woo et al., 1997). A total of
three living specimens were found in two stations. This biofacies represented the
nearshore marine environment.
Biofacies 3 (Figure 4.1, 4.2, Table 4.2) is composed of eighteen stations and is the
most widespread biofacies. It corresponds with the central sound basins (ALB01S2,
ALB01S3, ALB01S4, CUROISI, CUR01S5, CUR01S7, CUR01S9, CRO01S3) and
embayed tributary channels (PASOISI, NOROISI, NOR01S2), intertidal nearshore sand
66
Table 4.4. Occurrence (O), constancy (C), and biofacies fidelity (BF) for the four biofacies
that characterized the living populations.
Biofacies 1 Biofacies 2
Taxon O C BF 0 C BF
Ammoastuta inepta 1 1 10
Ammobaculites crassus 6 4 2
Ammobaculites dilatatus 1 1 2
Ammobaculites exiguus
Ammobaculites subcatenulatus 3 2 5
Ammonia parkinsoniana
Ammonia sp. (organic lining) 3 2 8
Ammotium salsum 6 5 2
Arenoparrella mexicana 2 1 10
Elphidium excavatum 2 10 10
Elphidium galvestonense
Haplophragmoides bonplandi 1 1 10
Jadammina macrescens 2 2 10
Miliammina fusca 12 9 7
Miliammina petila 1 1 10
Reophax sp.
Tiphotrocha comprimata 1 1 6
Trochammina inflata 1 1 10
Indeterminate unilocular sp.
Biofacies 3 Biofacies 4
Taxon O C BF O C BF
Ammoastuta inepta
Ammobaculites crassus 14 8 3 7 10 4
Ammobaculites dilatatus 2 1 3 1 1 4
Ammobaculites exiguus 5 3 10
Ammobaculites subcatenulatus 1 1 1 1 1 3
Ammonia parkinsoniana 1 1 10
Ammonia sp. (organic lining) 1 1 2
Ammotium salsum 18 10 5 5 7 3
Arenoparrella mexicana
Elphidium excavatum
Elphidium galvestonense 1 1 10
Haplophragmoides bonplandi
Jadammina macrescens
Miliammina fusca 6 3 2 1 1 1
Miliammina petila
Reophax sp. 1 1 10
Tiphotrocha comprimata 1 1 4
Trochammina inflata
Indeterminate unilocular sp. 1 1 10
67
and mud flats (PAM01S5, PAM01S7, PAM01S8, PAM01S9) adjacent to and within
marshes, and perimeter platform shoals (ALBOl S5, CROOISI). The number of species
ranges from one to seven and the biofacies is dominated by Ammotium salsum.
?j
Calculated numbers of specimens per 50 cm were higher than any other biofacies,
suggesting conditions were favorable for increased population growth.
The average relative abundances for species in Biofacies 3 (Table 4.3) shows
three species, Ammotium salsum (76%), Ammobaculites crassus (15%), and Miliammina
fusca (5%), characterize the biofacies. Values ofbiofacies fidelity for the three species
(Table 4.4) showed that Ammotium salsum was the most significant species forming the
biofacies with a high constancy value (10) and a moderate biofacies fidelity value (5).
Several rare species are confined to this biofacies with a high biofacies fidelity value
(10), but they usually occur at one station and thus have very low constancies. This
biofacies was interpreted to represent the estuarine environment extending from the
estuarine basin and channels to its upper limits in the intertidal zone.
Biofacies 4 (Figure 4.1,4.2, Table 4.2) is composed of seven stations mostly in
the eastern half of the AES on back-barrier shoals (ALBOl S6, ALBOl S8, ROAOISI,
PAM01S2), an intertidal sand flat (ROA01S7), a muddy embayed tributary channel
(PASOl S3), and a sandy sound channel (CROOl S2). Numbers of species averaged two
and ranged ifom one to four. Calculated numbers of specimens per 50 cm^ ranged from 4
(PAM01S2) to 2,520 (CROOISI), but the average (Table 4.2) was much lower than the
other estuarine biofacies, probably a result of the lack of food and the unstable sandy
substrate.
68
Ammobaculites crassus is the dominant species with an average relative
abundance (Table 4.3) of 83% for the biofacies. Ammotium salsum is less abundant,
comprising on average 15% of the biofacies. Values for biofacies fidelity (Table 4.4)
agree with the average relative abundance, where A. crassus has a moderate biofacies
fidelity of five with a high constancy of ten. The biofacies fidelity for A. salsum was low
at three and its constancy was moderate to high at seven. This biofacies was typical of
the estuarine shoal environment characterized by mobile sandy substrates.
4.5 Cluster Analysis of Surface Stations - Dead Assemblage
In analyzing the species proportions data for the dead assemblage, only those
species making up greater than 5% of any one sample were included in the cluster
analysis (27 species). The cluster analysis was performed on the transformed proportions
data for those 27 species. This was done to reduce noise in the data set caused by rare
species. The dendrogram produced by the cluster analysis (Figure 4.3) is composed of
four, five, seven, or eight nested groups. A plot of the five groups produced the most
ecologically meaningful pattern (Figure 4.3, 4.4, Table 4.5).
Biofacies A (Figure 4.3, 4.4, Table 4.5) is composed of six stations located along
the foreshore, shoreface and within the Oregon Inlet’s ebb- and flood-tidal delta complex.
The number of species was consistently low for each station with the exception of the
station on the shoreface (OFFOlSI), with eight species (Table 4.5). Calculated numbers
of specimens per 50 cm^ sample ranged from five (BEA01S3) to 270 (INSOISI) and
numbers were consistently lower on the foreshore by at least a factor of two compared to
69
o o
Biofacies Stations z z
INSOISI 135 3
EBBOISI 143 3
A BEAOISI 63 3
r
BEA01S3 5 2
OFFOISI 101 8
BEA01S2 10 3
ROA01S9 3 3
ROA01S7 254 14
ALU)1S4 49 4 >n
ALB01S8 220 5
CRO01S2 307 3
CR001S3 221 5
B
ALB01S5 294 5
ALB01S6 220 3
CRO01S6 240 10
ALLOISS 312 4
CROOISI 238 6
ROAOISI 290 5
AUjOISI 200 10
ALL01S5 294 7
CRO01S7 253 11
ROA01S2 87 6
PAM01S2 78 7
PAM01S6 219 93
PAM01S5 157 13
ROA01S4 320 15
PAM01S9 79 7
PAM01S7 92 4
c ALJL01S2 275 7
CUR01S7 259 6
CUR01S9 299 5 Ih
CUROISI 262 5
ALB01S3 230 5 y
CUR01S5 254 4
ALB01S4 219 6
NOROIS2 200 8
NOROISI 214 7
PASOISI 247 5
ALB01S2 207 5
PAS01S3 242 6
CUROISIO 104 7
D PAS01S2 253 6
ALBOISI 325 4
PAM01S8 11 3
ROAOIS5 238 16
E CRO01S4 239 14 Zn
CUR01S4 206 15
CUR01S2 282 12
Figure 4.3. Dendrogram produced by cluster analysis (Ward’s linkage, Euclidean distances) of
transformed proportions data for dead foraminifera. Only those taxa comprising five percent or more of
the assemblage in any one sample were included.
70
Figure 4.4. Map showing distribution of five biofacies identified by cluster analysis including dead
species comprising five percent or more of the assemblage in any one sample.
71
Table 4.5. Stations were grouped into biofacies (B) through cluster analysis of the dead assemblages
including only those species whose abundance was greater than 5 percent in any one sample.
Interpretations for each biofacies and values for species diversity (H(S)), equitability (E), number of
species (S), number of specimens picked (N), and calculated number of specimens per 50 cm^ (n) are listed
for each station.
B Interpreted environment Stations H(S) E S N n
A Nearshore marine INSOISI 0.21 0.41 3 135 270
and inlet EBBOISI 0.14 0.38 3 143 143
BEAOISI 0.16 0.39 3 63 63
BEA01S3 0.50 0.82 2 5 5
OFFOISI 0.80 0.28 8 101 101
BEA01S2 0.64 0.63 3 10 10
Mean 0.41 0.49 4 76 99
B Estuarine shoal ROA01S9 1.10 1.00 3 3 3
ROA01S7 1.60 0.35 14 254 2750
ALL01S4 0.27 0.33 4 49 49
ALB01S8 0.70 0.40 5 220 426
CRO01S2 0.63 0.63 3 307 5526
CRO01S3 0.64 0.38 5 221 5658
ALB01S5 0.64 0.38 5 294 6615
ALB0IS6 0.67 0.65 3 220 5120
CRO01S6 0.86 0.24 10 240 8956
ALL01S3 0.77 0.54 4 312 1755
CROOISI 0.75 0.35 6 238 10154
ROAOISI 0.85 0.47 5 290 104400
Mean 0.79 0.48 6 221 12618
C Estuarine ALLOISI 1.62 0.51 10 200 15360
ALL01S5 1.19 0.47 7 294 15120
CRO01S7 1.46 0.39 11 253 35683
ROA01S2 1.10 0.50 6 87 87
PAM01S2 1.34 0.55 7 78 78
PAM01S6 1.30 0.41 9 219 2336
PAM01S5 1.99 0.56 13 157 2355
ROA01S4 1.50 0.30 15 320 261669
PAM01S9 1.36 0.55 7 79 876
PAM01S7 0.83 0.57 4 92 613
ALL01S2 0.65 0.27 7 275 22629
CUR01S7 0.73 0.35 6 259 66304
CUR01S9 0.61 0.37 5 299 127163
CUROISI 0.62 0.37 5 262 15120
ALBO 1 S3 0.82 0.45 5 230 12295
CUR01S5 0.89 0.61 4 254 16256
ALB01S4 0.87 0.40 6 219 31392
NOR01S2 1.14 0.39 8 200 57600
NOROISI 1.32 0.54 7 214 13696
72
Table 4.5. Continued.
B Interpreted environment ST H(S) E S N n
PASOISI 1.13 0.62 5 247 5601
ALB01S2 1.13 0.62 5 207 5624
PASO I S3 1.29 0.61 6 242 13403
Mean 1.13 0.47 7 213 32785
D Inner estuarine CUROISIO 1.26 0.50 7 104 104
PAS01S2 1.25 0.58 6 253 12144
ALBOISI 1.16 0.80 4 325 10400
Mean 1.22 0.63 6 227 7549
E Marsh PAM01S8 1.09 0.99 3 11 13
ROA01S5 1.76 0.36 16 238 34272
CRO01S4 2.30 0.71 14 239 8749
CUR01S4 2.31 0.67 15 206 5028
CUR01S2 1.73 0.47 12 282 2689
Mean 1.84 0.64 II 195 10150
73
other stations within the biofacies. These lower numbers were most likely due to the
increased energy at the foreshore due to waves and currents causing an increase in
mechanical destruction of tests.
Species diversity and equitability were low, averaging 0.41 and 0.49, respectively.
The low diversity and equitability was caused by the high dominance of one species,
Elphidium excavatum, which comprised on average 89% of the assemblage at each
station (Table 4.6). The rest of the assemblage was generally characterized by rare
calcareous species such as Hanzawaia strattoni (3.8%), Elphidium subarcticum (1.9%),
Ammonia parkinsoniana (1.6%), and Ammonia tepida (0.3%). Agglutinated species were
only present at two sites (BEA01S2 and OFFOISI). BEAOISI possessed only one
specimen ofAmmobaculites crassus and OFFOISI possessed four rare species,
Ammobaculites crassus, Ammobaculites dilatatus, Arenoparrella mexicana, and
Tiphotrocha comprimata. The occurrence of these agglutinated estuarine and marsh
species on the shoreface and foreshore indicate that transport of foraminiferal tests is
occurring through Oregon Inlet. Conversely, the presence ofElphidium subarcticum
behind the barrier on the flood-tide delta of Oregon Inlet shows that inner shelf
foraminifera are being transported into the adjacent back-barrier estuarine environment
near the inlet. Biofacies fidelity and constancy calculations for Biofacies A (Table 4.7)
indicate that Elphidium excavatum. Ammonia parkinsoniana, and Hanzawaia strattoni
characterize Biofacies A with high biofacies fidelity and moderate to high constancy
values. Other rare calcareous species had high biofacies fidelity values (10) due to their
sole occurrence in this biofacies, but low constancy because they only occur at a few
74
Table 4.6. Average relative abundance for the 37 species of the dead assemblages in each biofacies.
Values expressed as an average percent of all the samples in a given biofacies. Values for the five most
abundant species are in bold for each biofacies.
Biofacies Biofacies Biofacies Biofacies Biofacies
Taxon A B C D E
Ammoastuta inepta 0.5 1.0 0.6 7.7
Ammobaculites crassus 2.5 67.6 23.1 9.4 16.8
Ammobaculites dilatatus 0.3 3.6 1.6 0.7 0.8
Ammobaculites exiguas 0.2 0.2 0.7 0.1
Ammobaculites subcatenulatus 0.6 5.3 49.3 3.7
Ammobaculites sp. 0.1
Ammonia parkinsoniana 1.6 0.2
Ammonia tepida 0.3
Ammonia sp. (organic lining) 0.1 0.8 0.3 0.1
Ammotium salsum 20.7 56.4 22.7 6.0
Arenoparrella mexicana 0.2 0.3 3.0
Buccella frígida 0.1
Elphidium excavatum 88.8 0.1
Elphidium galvestonense 0.1
Elphidium subarcticum 1.9
Elphidium sp. 0.1
Hanzawaia strattoni 3.8
Haplophragmoides bonplandi 0.1 0.1 4.1
Haplophragmoides hancocki 1.2
Haplophragmoides manilaensis 0.7 0.1 1.8
Haplophragmoides wilberti 3.5 0.3 1.2
Jadammina macrescens 1.1 0.6 0.6 7.0
Miliammina fusca 0.7 7.3 16.4 23.1
Miliammina petila 0.2 0.1 9.8
Pseudothurammina limnetis 1.6
Reophax nana 0.2
Reophax sp. 0.1 5.5
Siphotrochammina lobata 0.1 0.2
Tiphotrocha comprimata 0.2 0.2 0.4 3.2
Trochammina compacta 0.1
Trochammina inflata 0.7 0.8
Trochammina lobata
Trochammina "squamata" 0.1
Trochamminita irregularis 1.4
Trochamminita salsa 0.2 0.6
Indeterminate aggl. unilocular sp. 0.1
Indeterminate organic lining 0.1
75
Table 4.7. Occurrence (O), constancy (C), and biofacies fidelity (BF) for the five biofacies that
characterized the dead assemblages.
Biofacies A Biofacies B BiofaciesC
Species Name o c BF o c BF O C BF
Ammoastuta inepta 4 4 2 10 5 2
Ammobaculites crassus 2 3 1 10 9 2 22 10 3
Ammobaculites dilatatus 1 2 1 6 5 3 13 6 3
Ammobaculites exiguas 4 4 5 5 2 3
Ammobaculites subcatenulatus 4 4 2 11 5 3
Ammobaculites sp. 1 0 2
Ammonia parkinsoniana 4 7 9 1 0 1
Ammonia tepida 1 2 10
Ammonia sp. (organic lining) 3 3 3 8 4 2
Ammotium salsum 11 10 3 22 10 4
Arenoparrella mexicana I 2 1 6 3 2
Buccella frígida 1 2 10
Elphidium excavatum 6 10 9 2 1 1
Elphidium galvestonense 1 0 10
Elphidium subarcticum 2 3 10
Elphidium sp. 1 2 10
Hanzawaia strattoni 3 5 10
Haplophragmoides bonplandi 1 1 1 5 2 3
Haplophragmoides hancocki 0 0 0 1 0 1
Haplophragmoides manilaensis 0 0 0 5 2 3
Haplophragmoides wilberti 2 2 2 3 1 2
Jadammina macrescens 1 1 1 5 2 1
Miliammina fusca 8 7 2 21 10 4
Miliammina petila 3 1 2
Pseudothurammina limnetis
Reophax nana 1 0 2
Reophax sp. 2 1 2
Siphotrochammina lobata 3 1 3
Tiphotrocha comprimata 1 2 2 4 2 2
Trochammina compacta 1 0 2
Trochammina inflata 3 1 3
Trochammina lobata 1 0 10
Trochammina "squamata " 1 0 10
Trochamminita irregularis
Trochamminita salsa 1 0 1
Indeterminate aggl. unilocular sp. 1 1 10
Indeterminate organic lining 1 1 4 3 1 10
76
Table 4.7. Continued.
Biofacies D Biofacies E
Species Name O C BE o C BF
Ammoastuta inepta 2 7 3 4 6 3
Ammobaculites crassus 3 10 3 5 7 2
Ammobaculites dilatatus 1 3 2 2 3 1
Ammobaculites exiguas 1 1 2
Ammobaculites subcatenulatus 3 10 5 3 4 2
Ammobaculites sp. 1 1 8
Ammonia parkinsoniana
Ammonia tepida
Ammonia sp. (organic lining) 1 3 2
Ammotium salsum 3 10 4 3 4 1
Arenoparrella mexicana 1 3 3 3 4 4
Buccella frígida
Elphidium excavatum
Elphidium galvestonense
Elphidium subarcticum
Elphidium sp.
Hanzawaia strattoni
Haplophragmoides bonplandi 3 4 6
Haplophragmoides hancocki 3 4 9
Haplophragmoides manilaensis 3 4 7
Haplophragmoides wilberti 4 6 6
Jadammina macrescens 4 6 6
Miliammina fusca 3 10 4 5 7 2
Miliammina petila 4 6 8
Pseudothurammina limnetis 2 3 10
Reophax nana 1 1 8
Reophax sp. 2 3 8
Siphotrochammina lobata 2 3 7
Tiphotrocha comprimata 4 6 6
Trochammina compacta 1 1 8
Trochammina inflata 2 3 7
Trochammina lobata
Trochammina "squamata "
Trochamminita irregularis 2 3 10
Trochamminita salsa 2 3 9
Indeterminate aggl. unilocular sp.
Indeterminate organic lining
77
stations. Biofacies A is inteq^reted to represent the nearshore marine and inlet
environment.
Biofacies B (Figure 4.3, 4.4, Table 4.5) is composed of 12 stations located along
the perimeter platform (ALB01S5, ALL01S3, ALL01S4) and back-barrier sand shoals
(ALB01S6, ALB01S8, CROOISI, ROAOISI), tidal channels (CRO01S2, CRO01S3,
CRO01S6), and unprotected intertidal nearshore sand flats (ROA01S7, ROA01S9).
Number of species per station generally varied between three and five (Table 4.5). Two
stations, CROOl S6 and ROAOl S7, had the highest number of species for Biofacies B
with ten and fourteen, respectively. Calculated numbers of specimens per 50 cm^ sample
ranged from 3 (ROAOlS9) to 104,400 (ROAOISI).
Species diversity (Table 4.5) for Biofacies B was slightly higher (average 0.79)
than for Biofacies A due to average relative abundance of two species, Ammobaculites
crassus (67 %) and Ammotium salsum (21 %) (Table 4.6). Species diversity (H(S)) was
still relatively low as was equitability (0.48) due to the proportions of rare species in the
assemblage at each station. Stations situated near marshes (ALBOl S8, ALLOl S3,
CROOl SI, CROOl S6, ROAOl SI, ROAOl S7) have higher species diversity than other
stations within Biofacies B due to the inclusion of rare marsh species that were
transported into the estuarine environment. ROAOl S7 and ROAOl S9 had the highest
species diversity values (H(S) =1.60 and 1.10, respectively) because they were located
directly adjacent to an eroding marsh. The highest equitability among the 12 stations was
at ROAOl S9 (E=l .00), which was characterized by three species represented by one
specimen each. Calculations of biofacies fidelity and constancy (Table 4.7) show that no
78
species is definitively indicative of this biofacies because each estuarine and marsh
species has a wide ranging distribution within the study area. Instead, average relative
abundance gives the best indication of which species and more importantly, the species
proportions, that were important in the formation of this biofacies. For Biofacies B,
Ammobaculites crassus was most abundant and Ammotium salsum was common and both
taxa characterized this biofacies. Biofacies B was analogous to the estuarine shoal
environment characterized by mobile sand surfaces.
Biofacies C (Figure 4.3, 4.4; Table 4.5) was composed of 22 stations located in
the central sound basins (ALB01S2, ALBO 1 S3, ALBO01S4, CUROISI, CUR01S5,
CUR01S7, CUR01S9), embayed tributary channels (ALLOISI, ALL01S2, ALL01S5,
NOROISI, NOR01S2, PASOISI, PAS01S3), intertidal nearshore sand and mud flats
(ROA01S4, PAM01S5, PAM01S6, PAM01S7, PAM01S9), and higher salinity back-
barrier shoals (CRO01S7, ROA01S2, PAM01S2). Number of species averaged seven for
the biofacies with a range from four (CUR01S7 and PAM01S7) at an intertidal sand flat
to 15 at an intertidal creek adjacent to a fringing marsh (ROA01S4). Calculated numbers
of specimens per 50 cm^ ranged from 78 on a back-barrier sand shoal adjacent to Oregon
Inlet (PAM01S2) to 261,669 at ROA01S4.
Biofacies C is distinguished from Biofacies B in its higher average species
diversity (H(S) = 1.13) but with the similar equitability (average of E = 0.47) (Table 4.5).
Increased values of species diversity were a result of an increase in number of species at
each station in Biofacies C. Equitability values indicated that one species was dominant
{Ammotium salsum), accompanied by other lesser abundant species {Ammobaculites
79
crassus, Miliammina fusca, and Ammobaculites subcatenulatus) and finally rare species.
Rare species were marsh taxa (e.g., Ammoastuta inepta, Haplophragmoides bonplandi,
Haplophragmoides wilberti, Arenoparrella mexicana, Trochammina inflata, and
Tiphotrocha comprimata) (Table 4.6) transported into the estuarine environment, and
some agglutinated and calcareous estuarine species which live in higher salinity
environments around Oregon Inlet and the southern portions of Roanoke and Croatan
Sounds (e.g., Ammobaculites exiguus, Reophax sp.. Ammonia parkinsoniana, and
Ammonia sp.) (Table 4.6).
Ammotium salsum was most abundant in Biofacies C (Table 4.6) while
Ammobaculites crassus, Miliammina fusca and Ammobaculites subcatenulatus were
common. Biofacies fidelity (Table 4.7) indicated that Ammotium salsum, Ammobaculites
crassus, and Miliammina fusca have the highest constancy values (10) for Biofacies C,
but biofacies fidelity values were low indicating the broad distribution of these species
among other biofacies. Biofacies C is interpreted to represent the estuarine environment
distributed throughout the estuarine basins and embayed tributary channels with its upper
limits in the intertidal zone.
Biofacies D (Figure 4.3, 4.4; Table 4.5) was composed of only three stations, two
were located within the inner reaches of the estuary (ALBOl SI, PAS01S2) and one was
located on an intertidal sand flat adjacent to a marsh (CUROl S10). The biofacies had an
average of six species (Table 4.5). Calculated numbers of specimens per 50 cm^ sample
ranged from 104 (CUROl SI 0) to 12,144 (PAS01S2) in the central channel of the
Pasquotank River. Values of species diversity and equitability (Table 4.5) were higher in
80
this biofacies than previous biofacies; the average species diversity (H(S)) was 1.22 and
equitability (E) was 0.63. The highest species diversity value (1.26) was from
CUROISIO which was in 0.3 meters of water next to an eroding marsh. Analysis of
individual species numbers per sample shows that numbers were moderately even among
a few species {Ammobaculites subcatenulatus, Miliammina fusca, and Ammotium
salsum), especially in ALBOISI (E = 0.80) and PAS01S2 (E = 0.58). Species diversity
values at ALBOISI, PAS01S2, and CUROISIO seem to be affected equally by the
moderate to high equitability values and the number of species in the sample.
Average relative abundance (Table 4.6) of the four common species within this
biofacies indicates that Ammobaculites subcatenulatus dominates the assemblage at 49%,
Ammotium salsum was common at 23%, Miliammina fusca was common at 16%, and
Ammobaculites crassus was common at 9%. These four species had a constancy of ten
but low to moderate biofacies fidelity values (Table 4.7), confirming their importance to
Biofacies D. This biofacies was interpreted to represent the inner estuarine environment
usually indicative of stations near fresh water inflow.
Biofacies E (Figure 4.3, 4.4; Table 4.5) was composed of five stations located
along the shorelines of the eastern sounds, comprising fringing marshes (CUR01S2,
CUR01S4, CRO01S4, ROA01S5) and one station on an intertidal sand flat at the mouth
of a tidal creek adjacent to Oregon Inlet (PAM01S8). PAM01S8 had very low specimen
numbers picked (11) and it probably clustered with ROA01S5 and CRO01S4 because
these three samples have similar proportions ofAmmobaculites crassus and Miliammina
fusca. ROA01S9 and CRO01S4 contain 16 and 14 species, respectively.
81
Calculated total numbers of specimens per 50 cm^ sample ranged from 13
(PAM01S8) to 34,272 (ROA01S5). Average number of species for Biofacies E was 12
with the highest (16) at ROA01S5. Species diversity (Table 4.5) was the highest of all
biofacies in the dead assemblage with an average value for H(S) of 1.84 and a high of
2.31 at CUR01S4. The high values were clearly due to the high numbers of species at
each station and the moderate evenness of the common species (Table 4.5). Seven
species (Table 4.6) were common in Biofacies E, Miliammina fusca (23%),
Ammobaculites crassus (17%), M petila (10%), A. inepta (8%), Jadammina macrescens
(7%), Ammotium salsum (6%), and Reophax sp. (6%). The remaining seventeen species
were rare. Species that characterize this biofacies were all marsh foraminifera such as
Haplophragmoides bonplandi, Haplophragmoides hancocki, Haplophragmoides
manilaensis, Haplophragmoides wilberti, Jadammina macrescens, Miliammina petila,
Pseudothurammina limnetis, Tiphotrocha comprimata, Trochammina inflata,
Trochamminita irregularis, and Trochamminita salsa. These species had consistently
moderate to high biofacies fidelity values and low to moderate constancy values (Table
4.7). Biofacies E clearly represented the marsh environment surrounding the sounds.
4.6 Radionuclide and Sediment Trends
Radionuclide tracer data ( Pb, Cs, and Ra) were employed in this study to
aid in the understanding of recent sediment dynamics in the AES, spatially and down-
core. Radionuclide tracers were analyzed in 27 short cores (see Figure 1.3 and Table
1.1). Two of the core stations at East and South Lakes (EL02S1 and SL02S1) were
82
chosen as control stations for comparison with other short core radionuclide trends,
because both were in protected reaches of the AES. Inventories of excess ^''^Pb and '^^Cs
in all cores (Table 4.8) were calculated to assess sediment dynamics within the estuary
and localized sediment mixing. Sedimentation and mass accumulation rates (Table 4.9)
were calculated using the CF-CS model and represent a maximum rate for the length of
detectable excess ^’^Pb in the core (see Table 4.9 for maximum depth in each core). '^^Cs
was used to calculate sedimentation rates in order to compare with excess Pb rates.
Rates (Table 4.9) were calculated using the depth (interval midpoint) of the maximum
activity of '^^Cs down-core ('^^Cs peak assumed to be 1963) divided by the number of
years to date of coring. Treatment of radionuclide data was only meant to be a first-order
approximation of the sediment dynamics, not a detailed radionuclide modeling effort.
Down-core analysis of grain-size was performed (Letrick, 2003) and graphs of
each core were generated and presented with the radionuclide data (Appendix E). These
proportions were used to understand surface sediment trends in the AES and down-core
trends enabled better interpretation of radionuclide tracer profiles and foraminiferal
assemblages.
Expected inventories of excess ^'°Pb and '^^Cs for eastern North Carolina are 26.5
and 18.0 dpm cm'^, respectively (Benninger and Wells, 1993). Inventories for excess
^'*^Pb were above or near expected at seven stations, ALBOISI, ALB01S3, EL02S1,
SL02S1, PASOISI, PAS01S2, and CRO01S6 (see Figure 1.3, Table 4.8). The '^’Cs
down-core peak corresponding with the 1963 atmospheric maximum was only present in
four cores, ALBOISI, SL02S1, PAS01S2, and ROA01S4 (see Figure 1.3, Table 4.8).
83
Table 4.8. Radionuclide data for excess ^'°Pb and ''^^Cs are presented for 22 of 27 cores. The
remaining five cores were from the perimeter platform and back-barrier shoals with no
appreciable radionuclide activity. Initial activity is presented to show the variability within
the system and excess "''^Pb inventories were calculated for the whole core.
Excess 2l0pb 137C?s
Station Core Initial Initial
Core Length activity Inventory activity Inventory
(cm) (dpmg') (dpm cm ') (dpm g ') (dpm cm ')
ALBOISICI 0-40 8.77 52.41 1.54 32.46
ALB01S2C1 0-42 11.15 17.48 1.13 7.41
ALB01S3C1 0-42 11.36 21.32 1.16 4.57
ALB01S4C1 0-28 8.13 13.62 1.14 5.49
ALLOISICI 0-34 5.96 4.92 0.59 0.51
ALL01S2C1 0-22 6.58 15.48 0.65 6.18
ALLO1SSCI 0-28 3.89 7.01 0.38 0.99
EL02S1C1* 0-28 12.71 35.57 1.06 13.05
SL02S1C1* 0-30 26.72 91.85 2.69 20.65
PASOISICI 0-28 14.67 29.10 3.07 8.92
PAS01S2C1 0-40 11.36 24.09 1.62 19.33
PAS01S3C1 0-61 4.12 6.79 1.30 3.96
NOROISICI 0-34 7.27 19.08 0.76 4.72
NOR01S2C1 0-31 5.01 17.22 0.45 2.84
CUROISICI 0-31 0.34 1.50 0.09 0.84
CUR01S3C1 0-74 2.53 4.35 0.44 3.41
CURO 1 SSCI 0-40 0.77 2.32 0.11 0.36
CUR01S8C1 0-37 1.45 3.73 0.44 8.10
CRO01S3C1 0-15 0.91 1.83 0.07 0.14
CRO01S6C1 0-25 1.83 37.34 0.14 2.82
ROA01S4C1 0-51 1.63 18.05 0.06 6.63
*Porosities for each core were lost and were assumed (based on sedimentology) in
calculations for inventories and mass accumulation rates. Inventories and mass accumulation
rates are then a best approximate of actual.
84
Table 4.9. Sedimentation rates were calculated for excess‘'®Pb using the CF-CS model and for
'^’Cs by using the '^^Cs peak when present in the cores to compare with the excess''°Pb rates. All
sedimentation and mass accumulation rates were based on core midpoint intervals and should be
considered maximum rates. Calculation intervals of excess^'^Pb in cores represents the intervals for
which sedimentation rates were calculated. In some cases the excess^'^Pb profiles were subdivided
based on breaks in slope and rates were calculated accordingly. Errors and (based on linear
regression) values are presented for each interval. No sedimentation or accumulation rates were
calculated for sandy cores or where activity was limited to only the first interval.
Excess Pb 137 Cs
Station Calculation Sed. Mass Sed.
Core interval rate Error R^ accumulation Error R^ rate Error
(cm) (cm yf') (cm yf') (g cm ' yf') (cm yf') (cm yf') (cm yf')
ALBOISICI 1-23.5 0.57 0.07 0.90 0.21 0.03 0.90 0.54 0.04
Slope 1 1-17.5 0.74 0.16 0.81 0.34 0.08 0.80 — —
Slope 2 17.5-23.5 0.26 0.03 0.99 0.12 0.01 0.99 — —
ALB01S2C1 1-5.5 0.18 0.03 0.97 0.07 0.01 0.98 — —
ALB01S3C1 1-11.5 0.13 0.02 0.93 0.04 0.01 0.93 — —
ALB01S4C1 1-8.5 0.08 0.02 0.95 0.04 0.01 0.97 ___
ALL01S2C1 1-11.5 0.21 0.07 0.72 0.07 0.03 0.72 ___ —
ALL01S5C1 1-3.0 0.03 0.00 1.00 0.02 0.00 1.00
EL02S1C1* 1-13.0 0.13 0.02 0.86 0.06 0.01 0.86 ... —
SL02S1C1* 1-21.0 0.20 0.02 0.93 0.06 0.01 0.93 0.30 0.03
Slope 1 1-11.0 0.52 0.08 0.91 0.10 0.02 0.93 — —
Slope 2 11.0-15.0 0.10 0.00 1.00 0.03 0.00 1.00 — —
Slope 3 15.0-21.0 0.18 0.02 0.97 0.07 0.01 0.97 — —
PASOISICI 1-20.5 0.25 0.04 0.90 0.09 0.01 0.90 — —
Slope 1 1-5.5 0.11 0.01 1.00 0.04 0.01 0.96 — —
Slope 2 5.5-20.5 0.39 0.03 0.98 0.13 0.01 0.96 — —
PAS01S2C1 1-11.5 0.14 0.02 0.96 0.04 0.00 0.98 0.15 0.04
PAS01S3C1 1-8.5 0.16 0.02 0.96 0.05 0.01 0.95 — —
NOROISICI 1-5.5 0.13 0.03 0.95 0.08 0.01 1.00 — —
NOR01S2C1 1-8.5 0.11 0.01 0.99 0.13 0.02 0.97 — —
ROA01S4C1 5.5-17.5 0.33 0.04 0.96 0.08 0.01 0.98 0.26 0.08
*Porosities for each core were lost and were assumed (based on sedimentology) in calculations for
inventories and mass accumulation rates. Inventories and mass accumulation rates are then a best
approximate of actual.
85
Highest activities of '^^Cs in the remaining 22 cores were typically found at the surface
9 1 fj
decreasing down-core depending on sedimentology. In these 22 cores, excess Pb and
137Cs were typically below detectable activities generally near the same depths (10-15
cm) indicating the importance of physical and biologic sediment mixing (Dellapenna et
at., 2003) and resuspension of these tracer profiles (Christiansen and Emelyanov, 1995).
Initial activities of excess ^'°Pb and '^^Cs in surface sediments of cores vary
considerably throughout the study area (see Figure 1.3, Table 4.8). The highest initial
activity of excess ^'*^Pb (26.72 dpm g"') was found in the most protected reach of the
estuary at SL02S1. Initial activities at other stations were usually less than half that
activity. The lowest initial activities of excess ^’^Pb were found in the eastern sounds
(Table 4.8). Their low initial activity is due to the increased percentage of sand (> 63
pm) which has been linked to lower activities (He and Walling, 1996). Also, currents
that scour the shallow bottom due to wind events and tidal flushing most likely remove
newly deposited fine-grained sediment as indicated by surface activities and the low
percentage of fines in cores taken in these sounds. The highest initial activity of '^^Cs
occurs at the two most protected stations, SL02S1 (2.69 dpm g ‘) and PASOISI (3.07
dpm g '). The lowest initial activities were in Croatan and Roanoke Sounds (< 0.14 dpm
g')-
Down-core radionuclide trends were analyzed for each water body to facilitate
comparison within the system. Seven cores were collected in Albemarle Sound. Six
cores were taken along its axis (ALBOISI, ALB01S2, ALBO 1 S3, ALB01S4, ALB01S6,
ALBOl S8) and one core from the perimeter platform (ALBOl S5) (See Figure 1.3). Of
86
the six cores collected along the axis four were from the central basin and the two later
ones from the back-barrier sand shoals. The cores from the perimeter platform and back-
barrier shoals contained > 95% sand (> 63 pm) and had minor traces, if any, of excess
Pb and Cs, which is to be expected for sand-rich environments (Appendix E).
Cores taken in the central basin showed a gradational west to east radionuclide
trend. The core at ALBOISI (Figure 4.5, Table 4.8, 4.9, Appendix E) contained active
excess ^'^^Pb to depth of 23.5 cm and the '^’Cs profile showed a down-core peak
analogous with the 1963 atmospheric maximum at 20.5 cm. Also, the excess ^'°Pb
inventory for this core (52.41 dpm cm'^) was two and a half to three times higher than the
other central basin cores. The central basin cores, ALBOl S2, ALBO 1 S3, and ALBOlS4
(Figure 4.6, 4.7, 4.8, Table 4.8, 4.9, Appendix E), showed excess ^'*^Pb and '^^Cs
detectable to similar depths in each core (8.5 to 11.5 cm) with increasing activity levels
of each tracer to the surface. Profiles of ’^^Cs in these three cores yield important
information as to the sediment dynamics of the central basin (discussed below) in
contrast with those at the head of the estuary (ALBOl SI).
Sedimentation and mass accumulation rates (Table 4.9) gradually decrease to the
east in the central basin. ALBOl S 1C 1 was located east of the junction of the two major
river systems flowing into Albemarle Sound and is situated within the flocculation zone
of the estuary, causing it to be a major depositional center for fluvial clay and silt
entering the central basin. The profile of excess ^'^’Pb (Figure 4.5) could be broken into
two slopes (Slope 1 = 0.74 ± 0.16 cm yr'* and Slope 2 = 0.26 ± 0.03 cm yr '), which
indicated that sedimentation has increased over the last 19 cm of sediment in the core.
87
Albemarle Sound
ALBOISICI
2iopb^ 226Ra^ i37ç.g (dpm/g) Excess ‘'°Pb (dpm/g) X-radiograph
0 2 4 6 8 10 12 14 16 0.1 1 10
0 20 40 60 80 100
—Pb-210
Cs-137 Grain Size (% <63 jim)
—^ Ra-226
— % <63 pm
• XS Pb-210
Linear Regr.
Figure 4.5. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ALBOISICI, and the x-radiograph for the core (scale in centimeters) in Albemarle Sound. Note
changes in x-axes scale fi'om linear to log between both graphs. In the graph of excess ^‘"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rates and R squared values are for
the slope of the linear regressions.
88
Albemarle Sound
ALB01S2C1
2i0pb^ 226p^a, '”Cs (dpm/g) Excess ‘"’Pb (dpm/g) X-radiograph
0 2 4 6 8 10 12 14 16 0.01 0.1 1 10 100
0.09 cm yr"'
R'= 0.8916
I 1 1 1 1 1
0 20 40 60 80 100
Grain Size (% <63 pm)
—Pb-210
—Cs-137 —^— % <63 pm
—^ Ra-226 • XS Pb-210
Linear Regr.
Figure 4.6. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ALBO 1S2C1, and the x-radiograph for the core (scale in centimeters) in Albemarle Sound. Note
changes in x-axes scale fi'om linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression.
89
Albemarle Sound
ALB01S3C1
2i0pb^ 226^^ \37q^ (dpm/g) Exccss (dpiTl/g) X-radiograph
0 2 4 6 8 10 12 14 16 0.01 0.1 1 10 100
^ Pb-210
^ Cs-137 Grain Size (% <63 pm)
^ Ra-226
— % <63 pm
• XS Pb-210
Linear Regr.
Figure 4.7. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ALBO 1S3C1, and the x-radiograph for the core (scale in centimeters) in Albemarle Sound. Note
changes in x-axes scale fi'om linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression.
90
Albemarle Sound
ALB01S4C1
-'°Pb, "‘’Ra, ‘”Cs (dpm/g) Excess ^'°Pb (dpm/g) X-radiograph
0 2 4 6 8 10 12 0.01 0.1 1 10
Figure 4.8. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ALBO 1S4C1, and the x-radiograph for the core (scale in centimeters) in Albemarle Sound. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression.
91
The average sedimentation rate for excess was 0.57 ± 0.07 cm yr'' and the mass
accumulation rate was 0.21 ± 0.03 g cm" yr" . The sedimentation rate calculated from
the '^^Cs peak was 0.54 ± 0.04 cm yr '. The low initial excess ^'°Pb activity suggests a
few centimeters at least have been removed from the top portion of the core. Grain-size
analysis (Figure 4.5, Appendix E) showed relatively little change down-core. The X-
radiograph (Figure 4.5) showed rather homogenous sediments with a shell lag of
disarticulated Rangia cuneata (brackish water clams) and several others scattered through
the upper portion of the core.
The mid- and outer-central basin stations have only 10 to 13 cm of sediment
younger than 120 years, suggesting that sediment accumulation at these stations is
fundamentally different than at the head of the estuary. Sedimentation rates (Table 4.9)
for each of these stations were (from west to east) 0.18 ± 0.03, 0.13 ± 0.02, and 0.08 ±
0.02 cm yr ', respectively, and mass accumulation rates were 0.07 ± 0.01, 0.04 ± 0.01,
0.04 ± 0.01 g cm'^ yr '. The '^^Cs profiles (Figures 4.6-4.8) suggest that sedimentation
processes are dominated by resuspension events resulting in the increasing activity to the
surface (Christiansen et al., 2002). The fining-upward cycles, increasing organic content
(Letrick, 2003) to surface (Ligero et al, 2001), and less pronounced stair-stepped excess
9 10
Pb profile support this interpretation.
In the Alligator River, cores were analyzed from the head of the embayed
tributary (ALLOISI) down its central channel (ALL01S2, ALL01S5) and on the
perimeter platform (ALL01S3) (see Figure 1.3). At ALLOISI (Figure 4.9, Table 4.8, 4.9,
Appendix F) only the top two centimeters contained active excess Pb, with grain-size
92
Alligator River
ALLOISICI
2i0pb^ 226j^3^ i37ç^ (dpm/g) Exccss '"’Pb (dpm/g) X-radiograph
0 20 40 60 80 100
^ Pb-210
^ Cs-137 Grain Size (% <63 pm)
Ra-226
^— % <63 pm
• XS Pb-210
Linear Regr.
Figure 4.9. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ALLOISICI, and the x-radiograph for the core (scale in centimeters) in Alligator River. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^‘"Pb, samples within
error of zero were not included in the plot. No calculation of sedimentation rate was made for the core due
to its sandy nature and limited excess ^"Pb activity.
93
remaining fairly uniform down-core. With only two centimeters of laminated recent
sediment, this is probably an ephemeral layer underlain by an erosional surface showing
that unlike ALBOISI, very little sediment is transported in from the low-lying drainage
basin of the Alligator River. ALL01S2C1 (Figure 4.10, Table 4.8, 4.9, Appendix E) had
an excess ^'^Pb profile down to 20.5 cm and a faint '^^Cs high between 11.5 and 14.5 cm.
However, the fact that ’^’Cs is present to the depth at which excess ^'°Pb is dead, makes it
questionable whether this high can be considered an actual ’^^Cs peak analogous to 1963.
The sedimentation rate calculated from the excess ^'‘^Pb trend was 0.21 ± 0.07 cm yr '
and the accumulation rate was 0.07 ± 0.03 g cm' yr' . The core taken at ALLO 1 S3
(Figure 4.11, Appendix E) did not possess any excess ^'*^Pb activity. It was characterized
by a thin veneer (1 cm) of recent sand underlain by a bioturbated mud that was greater
than 120 years old. The X-radiograph of the core (Figure 4.11) showed a Rangia cuneata
in life position about 1 cm below the surface and burrows and plant roots were faintly
recognizable. ALLOl S5 (Figure 4.12, Table 4.8, 4.9, Appendix E) was very similar to
ALLOl SI in that it only had 4 cm of recent sediment. The shape of the excess ^'°Pb
profile (rapid decrease in activity with depth) suggests an erosional surface underlies the
4 cm of recent sediment (Figure 4.12). The sedimentation rate calculated for that
sediment layer was 0.03 ± 0.00 cm yr"'. Thus, only one core (ALLOlS2) shows
appreciable deposition in the Alligator River near its convergence with Albemarle Sound.
This was due to two possible reasons. First, the station is protected from long fetches by
the adjacent perimeter platform shoals to the north, east and west. Second, this station
could be in an area of sediment focusing in the Alligator River.
94
Alligator River
ALL01S2C1
0 20 40 60 80 100
Pb-210
^ Cs-137 Grain Size (% <63 |im)
^ Ra-226
—^— % <63 nm
• XS Pb-210
Linear Regr.
Figure 4.10. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of< 63 pm
(mud) for ALLO 1S2C1, and the x-radiograph for the core (scale in centimeters) in Alligator River. Note
changes in x-axes scale fi-om linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression.
95
Alligator River
ALL01S3C1
0 20 40 60 80 100
^ Pb-210
^ Cs-137 Grain Size (% < 63 (im)
Ra-226
% < 63 |im
XS Pb-210
Figure 4.11. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ALLOl S3C1, and the x-radiograph for the core (scale in centimeters) in Alligator River. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, all samples
were within error of zero not included in the plot. No calculations were made on this core due to the lack
of excess ^'"Pb activity.
96
Alligator River
ALL01S5C1
2i0pb^ 226Ra^ I37(-J (dpm/g) Excess -'“Pb (dpm/g) X-radiograph
Figure 4.12. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ALLO 1S5C1, and the x-radiograph for the core (scale in centimeters) in Alligator River. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression.
97
In East and South Lakes, which are two embayed tributaries of Alligator River
(see Figure 1.3), two cores were taken. Core analyses were limited to radionuclide and
grain-size data because no x-radiographs were taken of the cores. Porosities were
assumed for each core by matching the grain-size trend of the core with other cores
displaying similar grain-size trends (ALB01S2C1 was used for EL02S1C1 and
PASOl S2C1 was used for SL02S1 Cl ), thus allowing only an approximate of the excess
^'°Pb inventory and mass accumulation rates. The general trend of the excess ^’°Pb
activity above 14 cm in EL02S1C1 (Figure 4.13, Table 4.8, 4.9, Appendix E) increased
slightly up-core indicating a slightly increasing sedimentation rate to present. The active
layer of sediment appears to be underlain by an erosional surface as indicated by the
abrupt change to no excess Pb activity below 14 cm depth. The excess Pb inventory
was much higher than expected atmospheric deposition (35.57 dpm cm' ) and reflects
transport of sediment to this station from elsewhere in the lake system (i.e., sediment
focusing). ‘^^Cs activity generally increases up-core from 13 cm to a high of 1.4 dpm g"'
at 3 cm below the surface (Figure 4.13). This high was not treated as the '^^Cs peak in
the core (Figure 4.13) due to the increasing activity profile up-core which suggests
physical or biological mixing in the top few centimeters. The sedimentation rate (Table
4.9) for this core was 0.13 ± 0.02 cm yr'' and the mass accumulation rate was 0.06 ± 0.01
g cm'^ yr"'.
The core taken from SL02S1 (Figure 4.14, Table 4.8 4.9, Appendix E) showed the
highest excess ^'°Pb inventory (91.85 dpm cm'^) and the highest initial activity of excess
^'°Pb (26.72 dpm g''). This extremely high inventory suggests that this station was a
98
East Lake
EL02S1C1
^'“Pb, '^’Cs (dpm/g) Excess ‘‘“Pb (dpm/g)
0 2 4 6 8 10 12 14 16 18 0.01 0.1 10 100
I 1 1 1 ! 1
0 20 40 60 80 100
Grain Size (% <63 pm)
— % <63 pm
• XSPb-210
Linear Regr.
Figure 4.13. Illustration of radionuclide tracer profiles and grain-size, expressed as a percentage of < 63 pm
(mud) for EL02S1C1 in East Lake. No x-radiograph was obtained for this core. Note changes in x-axes
scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within error of zero were
not included in the plot or calculations. Sedimentation rate and R squared value are for the slope of the
linear regression.
99
South Lake
SL02S1C1
2i0pb^ 226j^3^ I37çg (dpm/g) Excess -"’Pb (dpm/g)
0 5 10 15 20 25 30 35 0.01 0.1 1 10 100
0 20 40 60 80 100
Pb-210
Cs-137 Grain Size (% <63 pm)
^ Ra-226
— % <63 pm
• XS Pb-210
Linear Regr.
Figure 4.14. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for SL02S1C1 in South Lake. No x-radiograph was obtained for this core. Note changes in x-axes
scale from linear to log between both graphs. In the graph of excess ^‘"Pb, samples within error of zero were
not included in the plot or calculations. Sedimentation rates and R squared values are for the slope of the
linear regressions.
100
depositional center which was receiving sediment from the surrounding lake and possibly
land system. The excess activity (Figure 4.14) was broken into three slope
segments (1-11 cm, 11-15 cm, and 15-21 cm) (Figure 4.14, Table 4.9) that indicates that
sediment input into this area has varied over time. The changes in slope indicate that
from past to present, the sedimentation pattern has fluctuated between 0.18 ± 0.02 to 0.10
± 0.00 to 0.52 ± 0.08 cm yr '. The average sedimentation rate (Table 4.9) for the core
was calculated to be 0.20 ± 0.02 cm yr"' and the average accumulation rate was 0.06 ±
0.01 g cm'^ yr''. The '^^Cs activity shows a down-core peak at 11 cm (Figure 4.14) and
the activity decreases gradually to the surface of the core, though still high compared to
data from other cores. The sedimentation rate from the '^’Cs peak was 0.30 ± 0.03 cm
yr''. The difference between the excess ^'°Pb and '^^Cs sedimentation rates was probably
due to the increase in sedimentation rate for the upper half of the core (Figure 4.14, Table
4.9), which represents a period of rapid sediment accumulation.
On the north of the Albemarle Sound the two embayed tributaries of the
Pasquotank and North River flow within drainage basins of higher relief than the
Alligator River to the south, which is mostly low-lying swamp forests and wetlands.
Three cores were taken from the Pasquotank River (see Figure 1.3), one at its mouth
(PASOISI) and two along its central channel (PAS01S2, PAS01S3). The grain-size trend
(Figure 4.15, Appendix E) for PASOISI Cl was fairly uniform down-core with one
abrupt increase in percent mud above 5.5 cm, which corresponded with laminations .seen
in the x-radiograph (Figure 4.15). This core records 22 cm of excess ^'"Pb active
sediments and has one of the highest average sedimentation rates in the AES at 0.25 ±
101
Pasquotank River
PASOISICI
2i0pb^ “'’Ra, ‘”Cs (dpm/g) Excess -'“Pb (dpm/g) X-radiograph
Figure 4.15. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for PASOISICI, and the x-radiograph for the core (scale in centimeters) in Pasquotank River. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rates and R squared values are for
the slope of the linear regressions.
102
0.04 cm yr'' (Table 4.9). '^^Cs in the core (Figure 4.15) was highest at the surface (3.07
dpm g’’) and had a very similar activity to the '^^Cs peak at 5.5 cm in core from
PASOl S2 (Figure 4.16). If both peaks were contemporaneous, a minimum sediment
layer of 7 cm was eroded from the surface of PASOl SI Cl. In addition, comparison of
excess ^'°Pb activities at the '^^Cs peak in both cores (Figure 4.15, 4.16) shows that
PASOl SI is 8.15 dpm g*' higher than PASOl S2. Differences in activity are probably
related to increased deposition at PASOl SI which is supported by the difference in
sedimentation rates between cores. Thus, the '^^Cs peak in PASOlSlCl exposed at the
surface indicates erosive sediment removal from this station.
The excess ^'®Pb inventory in PASOl S2C1 (Figure 4.16, Table 4.8, 4.9, Appendix
E) was near predicted at 24.09 dpm cm' with an initial activity of 11.36 dpm g ; there
was a down-core ’^^Cs peak at 5.5 cm. Sedimentation rates produced from excess ^''^Pb
and '^’Cs were nearly identical (0.14 ± 0.02 and 0.15 ± 0.04 cm yr ‘, respectively)
signifying uniform deposition throughout the active layer of sediment in the core. The
mass accumulation for the core was 0.04 ± 0.00 g cm' yr' .
PAS01S3 (Figure 4.17, Table 4.8, Appendix E) was located near the mouth of the
embayed tributary in its central channel (see Figure 1.3). The sediment dynamics at this
station appear to be drastically different from the previous stations upstream. The excess
^"^Pb inventory was only 6.79 dpm cm'^, indicating a net loss of sediment from this
station and the initial activity was 4.12 dpm g''. Only the top 8.5 cm contain active
excess ^'^Pb producing a similar sedimentation rate to PASOl S2C1 of 0.16 ± 0.02 cm yr"'
and a mass accumulation rate of 0.05 ± 0.01 g cm'^ yr''. The similarity in rates indicates
103
Pasquotank River
PAS01S2C1
2iopb^ --*Ra, '^'^Cs (dpm/g) Excess -'“Pb (dpm/g) X-radiograph
Figure 4.16. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for PAS01S2C1, and the x-radiograph for the core (scale in centimeters) in Pasquotank River. Note
changes in x-axes scale fi'om linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rates and R squared values are for
the slope of the linear regressions.
104
Pasquotank River
PAS01S3C1
-‘°Pb, ^-‘’Ra, '”Cs (dpm/g) Excess ='0pb (dpm/g) X-radiograph
0 1 2 3 4 5 6 7 0.01 0.1 1 10
0
10
20
30
O.
Q
40
50
60
—Pb-210
Cs-137 Grain Size (% <63 pm)
—^ Ra-226
— % <63 pm
• XS Pb-210
Linear Regr.
Figure 4.17. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for PAS01S3C1, and the x-radiograph for the core (scale in centimeters) in Pasquotank River. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression.
105
that sedimentation in the central channel of the embayed tributary is uniform. However,
the differences in inventory signify that PASO 1 S3 is subject to episodes of sediment
removal.
To the east of the Pasquotank River is the North River (see Figure 1.3) where two
stations (NOROISI, NOR01S2) were located on the east flank of the central embayed
channel. Radionuclide trends between both stations (Figure 4.18, 4.19, Table 4.8,
Appendix E) varied slightly, where activities in NOROl S2C1 were slightly lower than
those in NOROl SI Cl probably as a function of the higher percentage of sand in the top
15 cm of the core. This relationship between grain-size and activity was seen in the
variation in inventories, sedimentation rates, and mass accumulation rates. The
inventories were moderate for both stations, 19.08 (NOROlSlCl) and 17.22 dpm cm'^
(NOROl S2C1). The sedimentation rates from the excess ^'°Pb activity (Table 4.9) were
0.13 ± 0.03 and 0.11 ± 0.01 cm yr''. The mass accumulation rates varied from 0.08 ±
0.01 gcm'^yr ' inNOROlSlCl to 0.13 ± 0.02 g cm'^ yr ' inNOR01S2Cl (Table 4.9).
I ‘>“1
The Cs trends (Figure 4.18, 4.19) in these two cores (low values increasing to the
surface) are very similar to the that found in the central basin of Albemarle Sound and
stations within the Alligator River. This indicates that surface sediments in the North
River are affected by resuspension, possibly caused by wind events and currents. The
inventory of '^^Cs was most similar to cores in the Alligator River probably due to the
increased percentage of sand in the sediments.
The stations to the east and southeast in the Currituck (CUROISI, CURO 1 S3,
CUR01S5, CUR01S8), Croatan (CRO01S3, CRO01S6), and Roanoke Sounds
106
North River
NOROISICI
2i0pb^ 226Ra^ (dpm/g) Excess *"’Pb (dpm/g) X-radiograph
40 J I 1 1 1 1 1
0 20 40 60 80 100
—Pb-210
Cs-137 Grain Size (% <63 pm)
—^ Ra-226
— % <63 pm
• XS Pb-210
Linear Regr.
Figure 4.18. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for NOROISICI, and the x-radiograph for the core (scale in centimeters) in North River. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression.
107
North River
NOR01S2C1
2iopb^ --*Ra, '^’Cs (dpm/g) Excess ^'°Pb (dpm/g)
B
CJ
D.
O)
Q
0 20 40 60 80 100
^ Pb-210
^ Cs-137 Grain Size (% <63 pm)
Ra-226
— % <63 pm
• XS Pb-210
Linear Regr.
Figure 4.19. Illustration of radionuclide tracer profiles and grain-size, expressed as a percentage of < 63 pm
(mud) for NOR01S2C1 in North River. No x-radiograph was obtained for this core. Note changes in x-axes
scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within error of zero were
not included in the plot or calculations. Sedimentation rate and R squared value are for the slope of the
linear regression.
108
(ROAOISI, ROA01S4) (Figure 1.3, 4.20-4.27, Table 4.8, Appendix E) were generally
very sandy with the exception of ROA01S4, located in an intertidal marsh creek channel.
Because sand offers no adsorption for the radionuclides, activities were very low, causing
erratic profiles for excess ^'°Pb, and '^’Cs activities were at background levels. Thus,
inventories of the radionuclides were also very low. The high sand content in most of
these cores precluded calculations of sedimentation rates in all but ROA01S4.
The radionuclide trend in ROAOl S4 (Figure 4.27, Table 4.8, 4.9, Appendix E)
shows that a fairly continuous record of sedimentation has occurred at this station. The
x-radiograph (Figure 4.27) shows little structure with the exception of a few light-colored
laminations which correspond to sand laminations between darker organic-rich sandy
mud. The inventory of excess is below predicted (18.05 dpm cm'^), but the
sedimentation rate is fairly high at 0.33 ± 0.04 cm yr ' (calculated for the interval 5.5 to
17.5 cm). The sedimentation rate was calculated using this interval because it was linear
and was not affected by the lower activity of the upper 4 cm (a product of increased
percentage of sand). The '^^Cs peak is spread over two intervals (7-10 and 10-13 cm)
which is probably a function ofbiologic or physical mixing. The sedimentation rate
calculated from the '^^Cs peak (a midpoint of 10 cm in the broad peak was used) was
0.26 ± 0.08 cm yr"' and agreed well with the sedimentation rate from excess ^'^Pb,
indicating moderately uniform sedimentation.
109
Currituck Sound
CUROISICI
Figure 4.20. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for CUROISICI, and the x-radiograph for the core (scale in centimeters) in Currituck Sound. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot. No calculation of sedimentation rate was made for the core due
to its sandy nature and limited excess ^'‘*Pb activity.
no
Currituck Sound
CUR01S3C1
0 20 40 60 80 100
^ Pb-210
^ Cs-137 Grain Size (% <63 (im)
Ra-226
— % <63 |im
• XS Pb-210
Linear Regr.
Figure 4.21. Illustration of radionuclide tracer profiles and grain-size, expressed as a percentage of < 63 pm
(mud) for CUR01S3C1 in Currituck Sound. No x-radiograph was obtained for this core. Note changes in
x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within error of
zero were not included in the plot or calculations. Sedimentation rate and R squared value are for the slope
of the linear regression.
Ill
Currituck Sound
CUR01S5C1
2i0pb^ 226j^a, ‘”Cs (dpm/g) Excess -'”Pb (dpm/g) X-radiograph
0 1 2 3 4 0.01 0.1 1 10
Figure 4.22. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for CUR01S5C1, and the x-radiograph for the core (scale in centimeters) in Currituck Sound. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot. No calculation of sedimentation rate was made this core due to
its sandy nature and limited excess ^'"Pb activity.
112
Currituck Sound
CURO 1 SSCI
^'°Pb, “^Ra, ‘^’Cs (dpm/g) Excess "'“Pb (dpm/g) X-radiograph
Figure 4.23. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for CUR01S8C1, and the x-radiograph for the core (scale in centimeters) in Currituck Sound. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^'"Pb, samples within
error of zero were not included in the plot. No calculation of sedimentation rate was made for the core due
to its sandy nature and limited excess ^'"Pb activity.
113
Croatan Sound
CRO01S3C1
^'°Pb, 2-^Ra, ‘^^Cs (dpm/g) Excess "'“Pb (dpm/g)
0
2
4
6
c
cj
8
c.
o
Q 10
12
14
16
0 20 40 60 80 100
Pb-210
Cs-137 Grain Size (% <63 pm)
Ra-226
— % <63 pm
XS Pb-210
Figure 4.24. Illustration of radionuclide tracer profiles and grain-size, expressed as a percentage of < 63 pm
(mud) for CRO01S3C1 in Croatan Sound. No x-radiograph was obtained for this core. Note changes in
x-axes scale Irom linear to log between both graphs. In the graph of excess ^'"Pb, samples within error of
zero were not included in the plot. No calculation of sedimentation rate was made for the core due to its
sandy nature and limited excess ^'"Pb activity.
114
Croatan Sound
CRO01S6C1
Figure 4.25. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for CRO01S6C1, and the x-radiograph for the core (scale in centimeters) in Croatan Sound. Note
changes in x-axes scale fi'om linear to log between both graphs. In the graph of excess ^‘"Pb, samples within
error of zero were not included in the plot. No calculation of sedimentation rate was made for the core due
to its sandy nature and erratic excess ^'“Pb activity.
115
Roanoke Sound
ROAOISICI
0 20 40 60 80 100
Pb-210
^ Cs-137 Grain Size (% <63 (im)
Ra-226
—^— % <63 nm
—^ XS Pb-210
Figure 4.26. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ROAOISICI, and the x-radiograph for the core (scale in centimeters) in Roanoke Sound. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^"'Pb, samples within
error of zero were not included in the plot. No calculation of sedimentation rate was made for the core due
to its sandy nature and limited excess ^'"Pb activity.
116
Roanoke Sound
ROA01S4C1
2i0pb^ --*Ra, '^’Cs (dpm/g) Excess -‘“Pb (dpm/g) X-radiograph
ni')'?zisA7nni i in
Figure 4.27. Illustration of radionuclide tracer profiles, grain-size, expressed as a percentage of < 63 pm
(mud) for ROA01S4C1, and the x-radiograph for the core (scale is centimeters) in Roanoke Sound. Note
changes in x-axes scale from linear to log between both graphs. In the graph of excess ^"*Pb, samples within
error of zero were not included in the plot or calculations. Sedimentation rate and R squared value are for
the slope of the linear regression below the upper two intervals with decreased ^'"Pb activity that correlates
with an increase in grain-size.
117
4.7 Down-core Foraminiferal Populations and Assemblages
Three cores in the western and central Albemarle Sound (ALB01S1C2,
ALB01S3C2, and ALB01S4C2) (see Figure 1.3) were selected for foraminiferal analysis.
The living populations present in the cores were comprised of five species,
Ammobaculites crassus, Ammobaculites dilatatus, Ammobaculites subcatenulatus,
Ammotium salsum, and Miliammina fusca (Table 4.10). Table 4.10 lists the intervals
containing living specimens. All intervals were picked in ALB01S1C2 (0-37 cm). In
ALB01S3C2 and ALB01S4C2, all intervals down to 16 cm were picked and then every
third interval and the last interval. Numbers of living species in the cores varied from
one to four and calculated numbers of specimens per 50 cm^ varied from three to 4,032
(Table 4.10). The highest living numbers were generally in the upper two to four
centimeters of sediment. Calculated living numbers per 50 cm^ per interval were lowest
in ALB01S1C2 and dramatically increased at ALB01S3C2 and ALB01S4C2, suggesting
that an increase from near-fresh to low brackish salinities was more favorable for
population growth (e.g., A. salsum) in the central portion of Albemarle Sound.
Maximum depth of living foraminifera in ALBOl S1C2 was the interval of 22-25
cm; the next deepest record of live specimens was in the 8-10 cm interval (Table 4.10).
Miliammina fusca occurred down to 6 cm whereas A. salsum occurred in deeper samples.
Living foraminifera were present down to the 8-10 cm interval in ALBOl S3C2 (Table
4.10). A. salsum had the highest numbers of specimens (Table 4.10). In ALBOl S4C2
(Table 4.10) living foraminifera were present to only 4 cm. Proportions of species were
generally the same as in ALBOl S3C2.
Table 4.10. Living foraminiferal populations recorded at depth in three cores in the
western (ALB01S1C2) and central (ALB01S3C2, ALB01S4C2) Albemarle Sound.
Fraction picked (FP), number of species (S), numbers of living speciments picked (N),
and calculated specimens per 50 cm’ (n) are listed for each interval where living
specimens were found.
Core Depth (cm) FP S N n Anmcorhacsusliutes dAHmmaothactulitses Ammsuobhcalecnuullaitteus Amsmaolstium fMuiliasmcmaina
ALB0IS1C2 0-1 1/32 1 2 64 2
ALB01S1C2 1-2 1/40 1 3 120 3
ALB01SIC2 3-4 1/4 2 2 8 1 1
ALB01S1C2 4-6 1/4 1 1 4 1
ALB0IS1C2 6-8 11/60 1 1 5 1
ALB01SIC2 8-10 5/16 1 1 3 1
ALB01SIC2 22-25 1/60 1 1 60 1
ALB01S3C2 0-1 13/720 3 15 831 1 12 2
ALB01S3C2 1-2 11/720 3 3 196 1 1 1
ALB01S3C2 2-3 7/720 3 15 1543 1 1 13
ALB01S3C2 3-4 7/360 4 10 514 1 1 6 2
ALB0IS3C2 4-6 11/1440 2 6 785 1 5
ALB0IS3C2 6-8 1/240 3 7 1680 3 1 3
ALB0IS3C2 8-10 1/576 2 7 4032 1 6
ALB01S4C2 0-1 1/144 2 17 2448 7 10
ALB01S4C2 1-2 7/960 1 6 823 6
ALB01S4C2 2-3 11/2880 2 13 3403 3 10
ALB0IS4C2 3-4 1/320 2 10 3200 2 8
119
Fifteen taxa were recorded in dead assemblages in the cores (Table 4.11 ).
Comparison of dead foraminiferal assemblages down-core (Tables 4.11,4.12) with those
of the surface (Tables 4.5, 4.6, Appendix C, D) indicates only two biofacies are
recognizable in the cores. Biofacies C and D (Table 4.12). Biofacies C which represents
the Estuarine Biofacies was present from 6 cm to 37 cm in ALB01S1C2 and in all
samples from ALB01S3C2 and ALB01S4C2. Biofacies D which represents the Inner
Estuarine Biofacies was only present in the upper 6 cm of ALBOl SI C2.
Analysis of species diversity and equitability in ALB01S1C2 (Table 4.12)
indicates a gradual shift from higher to lower species diversity below 6 cm and an abrupt
decrease in equitability below 6 cm. These changes in species diversity and equitability
are consistent with the change in biofacies (Inner Estuarine to Estuarine down-core)
(Table 4.12) and reflect the more equitable assemblage above 6 cm and dominance of one
species (e.g., Ammotium salsum) below. Species diversity and equitability values in
ALB01S3C2 and ALB01S4C2 (Table 4.12) reflect the dominance of one species (e.g., A.
salsum) and are indicative of the Estuarine Biofacies.
4.8 Foraminiferal Taphonomy
4.8.1 Surface Assemblage
Comparison of the distribution of the living populations and the dead assemblages
in surface sediments shows at least three processes are active. First, marsh foraminifera
are being transported into the estuarine environment, most likely due to marsh shoreline
erosion and flushing of the fringing marshes during wind-tide flooding of the marsh
120
Table 4.11. List of three cores and counts of specimens per species from the dead down-core
assemblages for each interval.
||i ep a ||crass s dilat t s su c tenulatus l(ionrgianngic) s mexican sexcavatum bHaoplnopphralagmnoidesi a5oS .2cCore Depth (cm) 4fnmoastuia ‘immohaculites 4mmobaculites Ammobaculites Amsmpon.ia 'T Arenoparrella Elphiditim 1 Reonpahnaax Resopha.x Tironchjalmamtiana "Tsrqocuhaammainaa |l|iondregtiearmninaicteg
ALB01S1C2 0-1 15 149 53 108
ALB0ISIC2 1-2 0 133 59 99
ALB0IS1C2 2-3 2 153 24 92
ALB01SIC2 3-4 2 150 59 84
ALB01SIC2 4-6 13 75 79 63
ALB01SIC2 6-8 40 4 8 209 53
ALB0IS1C2 8-10 29 1 19 191 40
ALB0ISIC2 10-13 5 5 222 15
ALB01SIC2 13-16 5 5 5 162 7
ALB01SIC2 16-19 10 1 304 2
ALB01SIC2 19-22 0 223 11
ALB01S1C2 22-25 24 1 2 256 4
ALB01S1C2 25-28 67 9 247 13
ALB01S1C2 28-31 8 9 2 196 6
ALB01S1C2 31-34 33 1 245 9
ALB01SIC2 34-37 23 9 1 247 13
ALB0IS3C2 0-1 1 31 20 172 6
ALB0IS3C2 1-2 2 66 21 3 151 4
ALB01S3C2 2-3 1 59 7 4 215 2
ALB01S3C2 3-4 2 96 15 1 144 6
ALB01S3C2 4-6 1 73 19 3 198 7
ALB0IS3C2 6-8 4 52 13 6 270 5
ALB01S3C2 8-10 2 37 3 3 241 4
ALB01S3C2 10-13 2 30 1 5 220 1
ALB0IS3C2 13-16 2 70 2 9 277
ALB01S3C2 22-25 7 29 2 234
ALB0IS3C2 31-34 56 7 230 1 1 1
ALB0IS3C2 40-42 2 45 192 3 1 1
ALB01S4C2 0-1 1 73 5 4 135 1
ALB01S4C2 1-2 88 4 6 228 1 1
ALB01S4C2 2-3 2 117 9 178 1
ALB01S4C2 3^ 2 143 8 6 2 160 3
ALB01S4C2 4-6 3 102 4 211 2
ALB01S4C2 6-8 3 136 6 155 1
ALB01S4C2 8-10 108 6 204
ALB01S4C2 10-13 2 58 1 6 212
ALB01S4C2 13-16 35 5 253 1
ALB01S4C2 25-28 47 1 250
Table 4.12. Dead subsurface foraminifera. List of cores and calculations of species proportions, species diversity (H(S)), equitability (E),
total number of specimens picked (N), calculated numbers of specimens per 50 cm’ (n), and biofacies grouping with the surface greater than
5 percent dead assemblages. In cases where a species' proportion within a sample was less than half of a percent an X was used to
represent that value.
Core Depth (cm) H(S) E S N n G3iorofaucpieisng ||iminme § d.oapsttuata immcobracsusliutes dimimlaobtactuulitess jjimmsoubcaatceunuliltaetuss ||li(imonsrmgioanpngi.ac) ||4msmaolst!um irenompeaxricreanlla Elphexicdaviautumm Hbaoplonpphralagmnoideis Kfufiliasmca § C/lmina i 11 Tironchfalammtaina |"T|srqocuhammaitna |Indeterlmi|noinrgiaanteicg
ALB0ISIC2 0-1 1.16 0.8 4 325 10528 D 0.05 0.46 0.16 0.33
ALB0ISIC2 1-2 1.05 0.95 3 291 11760 D 0.46 0.20 0.34
ALB0IS1C2 2-3 0.94 0.64 4 271 1755 D 0.01 0.56 0.09 0.34
ALB0IS1C2 3-4 1.06 0.72 4 295 1192 D 0.01 0.51 0.20 0.28
ALB0ISIC2 4-6 1.25 0.87 4 230 916 D 0.06 0.33 0.34 0.27
ALB0IS1C2 6-8 0.98 0.53 5 314 1718 C 0.13 0.01 0.03 0.67 0.17
ALB0IS1C2 8-10 0.98 0.53 5 280 899 C 0.10 X 0.07 0.68 0.14
ALB0ISIC2 10-13 0.42 0.38 4 247 3406 C 0.02 0.02 0.90 0.06
ALB0ISIC2 13-16 0.53 0.34 5 184 184 C 0.03 0.03 0.03 0.88 0.04
ALB0IS1C2 16-19 0.2 0.31 4 317 5187 C 0.03 X 0.96 0.01
ALB0IS1C2 19-22 0.19 0.6 2 234 742 C 0.95 0.05
ALB0IS1C2 22-25 0.42 0.31 5 287 17280 c 0.08 X 0.01 0.89 0.01
ALB01SIC2 25-28 0.77 0.54 4 336 1596 c 0.20 0.03 0.74 0.04
ALB01SIC2 28-31 0.5 0.33 5 221 884 c 0.04 0.04 0.01 0.89 0.03
ALB01SIC2 31-34 0.51 0.42 4 288 810 c 0.11 X 0.85 0.03
ALB01S1C2 34-37 0.61 0.37 5 293 3780 c 0.08 0.03 X 0.84 0.04
Table 4.12. Continued.
1
2
S 1 ç
3 g
5
Core Depth (cm) H(S) E S N n G3iorofaucpieisng ||iminmeoapsttuata ||c ¡ g ó. gimmobracsusliutes dimilmaothactuulitess immsoubcaacleunultiatleus ||li(mionsrmgioanpnig.ac ) ||sal s 1 g 1immotsium irenompeaxricreanlla 3 1A Í Kfuiiliasmcmiana ë 1 51 & |T|rionchJaJmamtinaa fi; li ondregtiearmninaicteg
ALB01S3C2 0-1 0.82 0.45 5 230 6439 C X 0.13 0.09 0.75 0.03
ALB01S3C2 1-2 1.02 0.46 6 247 16364 C 0.01 0.27 0.09 O.OI 0.61 0.02
ALB0IS3C2 2-3 0.75 0.35 6 288 31166 C X 0.20 0.02 0.01 0.75 0.01
ALB01S3C2 3-4 1.01 0.46 6 264 14091 C 0.01 0.36 0.06 X 0.55 0.02
ALB01S3C2 4-6 0.95 0.43 6 301 48320 C X 0.24 0.06 0.01 0.66 0.02
ALB01S3C2 6-8 0.79 0.37 6 350 47258 C 0.01 0.15 0.04 0.02 0.77 0.01
ALBOIS3C2 8-10 0.6 0.31 6 290 71760 C 0.01 0.13 0.01 0.01 0.83 0.01
ALB0IS3C2 10-13 0.54 0.29 6 259 150336 C 0.01 0.12 X 0.02 0.85
ALB0IS3C2 13-16 0.67 0.39 5 360 155077 C 0.01 0.19 0.01 0.03 0.77
ALB01S3C2 22-25 0.5 0.41 4 272 74606 C 0.03 0.11 0.01 0.86
ALB0IS3C2 31-34 0.66 0.32 6 296 30446 C 0.19 0.02 0.78 X X X
ALB0IS3C2 40-42 0.66 0.28 7 245 3920 C 0.01 0.18 0.78 0.01 X X
ALB0IS4C2 0-1 0.87 0.4 6 219 33840 C X 0.33 0.02 0.02 0.62 X
ALB0IS4C2 1-2 0.77 0.36 6 328 45806 C 0.27 0.01 0.02 0.70 X X
ALB0IS4C2 2-3 0.84 0.46 5 307 83782 c 0.01 0.38 0.03 0.58 X
ALB0IS4C2 3-4 0.98 0.38 7 324 106880 c 0.01 0.44 0.02 0.02 0.01 0.49 0.01
ALB01S4C2 4-6 0.77 0.43 5 322 206080 c 0.01 0.32 0.01 0.66 0.01
ALB01S4C2 6-8 0.84 0.46 5 301 173376 c 0.01 0.45 0.02 0.51
ALB01S4C2 8-10 0.73 0.69 3 318 228960 c 0.34 0.02 0.64
ALB01S4C2 10-13 0.67 0.39 5 279 160704 c 0.01 0.21 X 0.02 0.76
ALB01S4C2 13-16 0.47 0.4 4 294 282240 c 0.12 0.02 0.86 X
ALB0IS4C2 25-28 0.46 0.53 3 298 24429 c 0.16 X 0.84
122
123
surface. Transport of estuarine and marsh foraminifera onto the inner shelf is occurring
through Oregon Inlet and, conversely, open shelf foraminifera (e.g., Elphidium
subarcticum) are being transported into the back-barrier inlet shoal environment, either in
suspension or as bedload. However, in most cases the transported individuals are rare in
samples and do not alter a sample’s faithfulness to a biofacies. Second, dissolution of
living calcareous foraminiferal tests ofAmmonia parkinsoniana and E. galvestonense is
occurring in the nearshore and intertidal estuarine environment probably due to decreased
calcium carbonate availability where salinity is less than 15 (Grossman and Benson,
1967) and due to corrosive sediment pore-waters (Murray and Alve, 1999a, b). Though
calcareous species were not particularly abundant in the back-barrier environment, where
they were present (PAM01S5) there was a significant difference between the living and
dead abundances (i.e., 29% versus 5% for yl. parkinsoniana) (Appendices B and D). This
indicates that although calcareous species can be a significant component of the living
population, dissolution of tests results in a relative increase in abundance of agglutinated
species in the dead assemblage. Third, mechanical destruction of calcareous tests by
currents and wave action in the foreshore and inlet environment presumably decreases
numbers of individuals significantly.
Comparison of the four living and five dead surface biofacies yields important
insight into the taphonomic processes that result in the dead assemblage. Both cluster
analyses (Figures 4.2, 4.4) recognized similar biofacies, with the exception of Biofacies 1
in the living cluster analysis, which represented a mixture of three biofacies from the
dead cluster analysis (e.g.. Biofacies D and E and some stations comprising Biofacies C).
124
Due to the extremely low numbers of specimens comprising the living population at
many of the stations (Table 4.2) and that the living population only represents a
“snapshot” of the present conditions and do not reflect seasonal test inputs, the living
biofacies was most useful in understanding the taphonomic processes operating to form
the dead assemblage, the living distribution of species at the time of sampling and the
environments they live in. On the other hand the dead assemblage reflects the time-
averaged test inputs of the living population and the taphonomic processes that in any
way alter the assemblage (Murray and Alve, 1999a, b).
4.8.2 Down-core Assemblage
Analysis of the living and dead individuals in ALBOISICI, ALB01S3C1, and
ALBOl S4C1 suggests that the infaunal living population (Table 4.10) does not alter the
dead assemblage as it transitions to a fossil assemblage, firstly because the infaunal
occurrences of the two dominant living species {Ammotium salsum and Miliammina
fusca) do not differ from the abundant species in the dead assemblage, and secondly
because the number of live specimens are so low. In the two central Albemarle cores
(ALBOl S3C2 and ALBOl S4C2) agglutinated foraminiferal tests were often pyrite filled.
All intervals picked in ALBOlS3C2 below 4 cm and four intervals in ALBOl S4C2 (4-6,
6-8, 10-13, 13-16) contained pyrite-infilled agglutinated tests.
Evidence of test destruction via dissolution of calcareous tests was indicated by
the presence oïAmmonia sp. organic linings in ALBOl S3C2 and ALBOlS4C2 (Tables
125
4.11,4.12) (Murray and Alve, 1999a, b). A single specimen of Elphidium excavatum
was found at the base of ALB01S3C2; the lack of more could be due to test dissolution.
Changes in numbers of specimens (n) down-core (Table 4.12) could be affected
by sediment resuspension of the sediment column. In both ALB01S3C2 and
ALB01S4C2, numbers of specimens (Table 4.12) were generally greatest between 13-16
cm decreasing to the surface (changes in specimen numbers were not considered below
16 cm due to the gaps between sampled intervals). This trend could represent a
winnowing effect. As sediments are resuspended, foraminiferal tests are carried in
suspension away from a station. The impact of resuspension on the tests in these cores
does not appear to be a selective process, since the composition of the assemblages are
fairly uniform down-core. Also, taxa (e.g., Arenoparella mexicana, Haplophragmoides
bonplandi, Trochammina inflate, and Trochammina "squamata") found at depth in
ALB01S3C2 and ALB01S4C2 indicate transport of marsh foraminifera to the central
basin presumably from shoreline erosion. However, the numbers of specimens in
ALB01S4C2 were higher than in ALB01S3C2 and could be attributed to the addition of
resuspended foraminiferal tests from elsewhere and/or higher test productivity due to
slightly higher brackish salinity (Ellison and Nichols, 1970).
4.9 Paleoenvironmental Analysis of the Albemarle Cores
Down-core radionuclide trends (Figures 4.5-4.7) in ALBOISICI, ALB01S3C1,
and ALBOl S4C1 were used to develop a geochronology within which paleoenviron-
mental changes in western and central Albemarle Sound based on foraminiferal
126
assemblages (Table 4.12) could be placed. The dead foraminiferal surface assemblages
were used as the basis for paleoenvironmental interpretations. The living populations in
the cores were used to assess taphonomic processes and the depths that foraminifera live
in the sediment.
The dead assemblage in ALB01S1C2 documents a shift from a dominantly
brackish estuarine basin assemblage characterized by an assemblage ofAmmotium
salsum (Biofacies C) to a more diverse inner estuarine basin assemblage characterized by
co-dominance ofAmmobaculites subcatenulatus and Miliammina fusca with lesser
numbers ofA. salsum (Biofacies D). This biofacies transition has two possible
explanations. Based on sedimentation rates calculated from excess ^'®Pb and '^’Cs data
(Table 4.9), this change at 6 cm occurred sometime in the early to middle 1990’s. This
period corresponds with increased hurricane and tropical storm activity along the North
Carolina coast which could have increased freshwater inflow from the Roanoke and
Chowan Rivers (Riggs and Ames, 2003). However, comparison of the living population
in the ALB01S1C2 (Table 4.10) which indicated that two different species were living
{Miliammina fusca and Ammotium salsum) above and below the biofacies transition with
radionuclide data from Corbett et al. (2004) supported a different interpretation from the
previous. Corbett et al. (2004) indicated that the upper 6 cm of sediment which
corresponded with Biofacies D was likely an ephemeral layer of sediment eroded from
upstream in the fresher reaches of the estuary and deposited over the low-brackish
estuarine biofacies (Biofacies C). Thus, the two biofacies recognized in ALB01S1C2
indicate that this station has likely been influenced by either increased freshwater inflow
127
due to increased storm activity beginning in the early to mid 1990’s causing the biofacies
transition or it is influenced by ephemeral deposition of inner estuarine sediments over
top of low-brackish estuarine sediments.
Analysis of ALB01S3C2 and ALBOl S4C2 only showed one biofacies present in
the cores (Biofacies C) (Table 4.12). Trends in rare species {Ammonia sp. and Elphidium
excavatum) (Table 4.11,4.12) were used to provide insight into historie environmental
changes recorded in the central portion of Albemarle Sound. Radionuclide trends
indicate sedimentation rates of 0.13 ± 0.03 cm yr*' and 0.08 ± 0.02 cm yr ' (Table 4.9).
Therefore, one centimeter in ALBOl S3C2 and ALBOl S4C2 represents approximately
eight and twelve years of sediment accumulation, respectively. Assemblages in down-
core intervals of 3 cm represent about 24 to 36 years, respectively, of test accumulation.
In this study. Ammonia sp. was found living (Appendix A) only in the back-
barrier estuarine environment with salinities greater than 8 near Oregon Inlet, though
living specimens made up no more than 5% of an assemblage. Bottom salinities at
ALB01S3 and ALB01S4 were 4 and 5 (Table 4.1), and based on data from Williams et
al. (1973), salinities at these stations range between nearly fresh to 5. In ALBOl S3C2
and ALBOl S4C2, Ammonia sp. organic linings were present, though rare (Table 4.11).
The distribution ofAmmonia sp. organic linings in each core extends up-core from 32.5
cm (250 yr BP) to 1.5 cm (12 yr BP) in ALBOlS3C2 and from 14.5 cm (181 yr BP) to
3.5 cm (44 yr BP) in ALBOl S4C2; this might reflect the taphonomic affects of
resuspension which possibly smeared distributions up-core. Thus, the presence of
Ammonia sp. in ALBOl S3C2 and ALBOlS4C2 suggest that Albemarle Sound was under
128
more marine influence at least two centuries ago when it was less isolated due to inlet
openings in the Currituck and Roanoke Sounds prior to 1828 (Dunbar, 1958).
Only one calcareous test of Elphidium excavatum was found in the deepest
interval in ALBOl S4C2 (40-42 cm) (Table 4.11 ). Although only one specimen was
found, taphonomic loss of additional specimens is possible as indicated by the presence
of only organic test linings ofAmmonia sp. However, E. excavatum is only found within
the back-barrier shoals in the dead assemblage adjacent to Oregon Inlet. In addition, a
study by Abbene et al. (2004) in the adjacent Pamlico Sound to the south of the present
study area indicates that E. excavatum is living on the back-barrier shoals of Halteras and
Ocracoke inlets (see Figure 1.1). West of Halteras and Ocracoke Inlets in the central
basin of Pamlico Sound, E. excavatum is living in co-dominance with Ammotium salsum.
Further to the west and north this assemblage transitions to one dominated by Ammotium
salsum with rare E. excavatum and Ammonia parkinsoniana. These present trends offer a
modem analogue for the oceanographic conditions of central and eastern portions of the
Albemarle Sound prior to 1828.
CHAPTER 5
DISCUSSION
5.1 Relationship of Environmental Conditions to Foraminiferal Distributions
Distributions of living and dead foraminifera were most influenced by sediment
type and salinity. The living and dead biofacies indicated that two abundant species,
Ammotium salsum and Ammobaculites crassus, preferred different substrate types within
the AES. A. salsum characterized the central basin of the trunk and embayed tributaries
which are generally low energy and consist of organic-rich mud (Riggs, 1996). However,
A. crassus favored the higher energy and more mobile sand substrates of the estuarine
perimeter platform and back-barrier shoals. A. crassus has a similar distribution in the
James (Nichols and Norton, 1969) and Rappahannock Rivers (Ellison and Nichols, 1970)
of Virginia. These authors, however, related the distribution ofA. crassus to the lower
salinity water mass (< 15) in the inner estuary. Grossman and Benson (1967) recognized
a similar distribution for crassus in the Pamlico and Neuse Rivers that flow into
Pamlico Sound to the south of the AES. All three earlier studies recognized a transition
to an Elphidium fauna seaward of a salinity of 15. Salinities >15 are restricted in the
study area to the vicinity of Oregon Inlet and the southern portions of Croatan and
Roanoke Sounds. Periodic wind and storm events cause perturbations to this pattern
pushing higher salinity waters deeper into the AES but these conditions are ephemeral
(Pietrafesa et al., 1986; Pietrafesa and Janowitz, 1991). Thus, an Elphidium fauna is not
able to colonize the outer reaches of the AES. South of Oregon Inlet, as the AES
130
transitions into the deeper and more saline (> 15) Pamlico Sound, Abbene et al. (2004)
demonstrated Elphidium is present along with moderate to high abundances ofA. salsum.
This indicates that A. salsum is more tolerant of a wider range of salinities than A.
crassus. A similar distribution ofA. salsum was reported by Poag (1978) in Galveston
Bay, Texas.
Other agglutinated species such as Ammobaculites exiguus and Reophax sp.,
though mostly rare in the estuary, were only found above salinities of 8 in Croatan,
Roanoke, and Pamlico Sounds. Miliammina fusca (living and dead) was common to
most abundant in environments with extreme variability (i.e., near freshwater inflow, in
marshes, and intertidal flats) (e.g., ALBOISI, CRO01S4, ROA01S4, ROA01S5,
PAM01S5, PAM01S7, PAM01S8, PAM01S9). A similar distribution was recognized by
Nichols and Norton (1969) and Ellison and Nichols (1970) in the James and
Rappahannock estuaries of Virginia. Live specimens of common and rare calcareous
species. Ammonia parkinsoniana. Ammonia sp., and Elphidium galvestonense, in the
AES were limited to the high salinity nearshore estuarine waters adjacent to Oregon Inlet
and the southern shores of Roanoke Island. Due to the moderate brackish salinities
(between 9-15) and limited calcium carbonate available (Grossman and Benson, 1967),
the calcareous tests exhibited dissolution of rose Bengal stained (i.e., live) specimens.
131
5.2 Paleoecological Implications: Relationship of Living and Dead Biofacies to
Environments
Analysis of the living populations and the dead assemblages via cluster analysis
identified four living biofacies and five dead biofacies (Figure 4.1-4.4, Table 4.2, 4.5).
Comparison of relationships between the living and dead biofacies and their interpreted
environments indicates that both sets of biofacies represent similar ecologically distinct
environments in the AES. Each cluster analysis indicated a marine (Biofacies 2 and A),
estuarine (Biofacies 3 and C), and estuarine shoal (Biofacies 4 and B) biofacies, which
included nearly identical stations (Table 4.2, 4.5). However, Biofacies 1 of the living
population consisted of a mixture of environments that were distinguished in the dead
cluster analysis (e.g.. Biofacies D and E and some stations comprising C) (Table 4.2,
4.5). Overall, there is good agreement between both cluster analyses, which indicates
that the living populations transfer to the dead assemblage without much significant
taphonomic alteration.
The low number ofbiofacies recognized indicates that estuarine foraminiferal
distributions are broad and taxa tolerate wide variations of environmental conditions.
Few biofacies were also recognized by Culver et al. (1996) and Woo et al. (1997) in the
back-barrier lagoons of the Delmarva Peninsula. Two of the biofacies in this study were
recognized down-core and have been used to reconstruct environmental changes in the
AES over the past few hundred years. Thus, the biofacies (dead assemblages) recognized
in this study should be a useful tool in distinguishing environmental changes in late
Quaternary deposits of coastal North Carolina and the adjacent region.
132
5.3 Fate of Sediments in the AES
Grain-size and percent organic matter (OM) data (Letrick, 2003) from the surface
and down-core sediments in the AES showed that ORM was the dominant sediment type
in the central basin portion of the AES and the embayed tributary channels. Sediments
transitioned to fine to medium sands on the perimeter platform and the back-barrier
shoals at the mouth of Albemarle Sound (Letrick, 2003). Sediments in the eastern sounds
consisted of mostly silty- to clayey-fine sands along their central axis and coarsened
toward their perimeters, back-barrier shoals and in regions of strong currents (Letrick,
2003).
Effects of environmental variables on radionuclides ( Pb, Cs, and Ra) were
varied but were consistent with other findings (He and Walling, 1996; Ligero et al.,
2001). Generally, sandier environments had very low to no activities of ^'^Pb and '^’Cs
which was consistent with He and Walling’s (1996) findings. Comparison of percent
organic matter down-core (from Letrick (2003) data) with radionuclide data show that
i 37Cs activities have similar trends as percent OM in cores affected by resuspension. This
relationship was also recognized by Ligero et al. (2001). Studies by Christiansen and
Emelyanov (1995) and Christiansen et al. (2002) have also shown that increasing up-core
activity of '^^Cs can be attributed to a mixed layer settled from resuspended sediments.
The impact of salinity on adsorption of '^^Cs is very slight due to the low broad salinity
gradient in Albemarle Sound, but decreased activities from ALBOISICI to ALBOl S4C1
could also result from resuspension related desorbtion of '^^Cs by NH ¡ pore water
(Johnson-Pyrtle and Scott, 2001).
133
Biological mixing (macro-benthic) appears to be minimal in the AES as indicated
by the lack of biological structures and dominant occurrence of laminations in x-
radiographs. The presence of Rangia cuneata in some cores was due to post-mortem
transport from the perimeter platform shoals where they live (personal communication,
S.R. Riggs, March, 2002).
Sedimentation rates in the AES (Table 4.9) averaged 0.13 cm yr ', excluding
stations which were above predicted atmospheric inventory (Table 4.8). Stations above
predicted atmospheric inventory represented depositional centers with greater
sedimentation rates. Sager and Riggs (1998) took a series of vibracores along north-
south transects in Albemarle Sound and correlated them based on lithoseismic and
chronostratigraphic techniques and data on heavy metal concentrations in the sediments
(Riggs et al., 1993). Sager and Riggs (1998) concluded that the modem ORM averages
approximately 0.5 m in thickness in the central basin of Albemarle Sound and represents
< 400 years ofpost-colonial sedimentation. Immediately underneath the modem ORM
and separated by a 1,100 year hiatus are laminated muds and fine sands which were
deposited in open-estuarine conditions (Sager and Riggs, 1998). Using the average
thickness of the ORM and the approximate age constraint of the ORM thickness, a post-
colonial average accumulation rate for sediments in Albemarle Sound is 0.13 cm yr ',
about 60% less than rates recorded in Chesapeake Bay tributaries (Bmsh, 1984). This
average accumulation rate is in agreement with the average decadal rate for this study,
suggesting that the accumulation rate for the top 10-15 cm of sediment in the AES has
been steady for the 0.5 m thickness of the modem ORM. Riggs (1996) further concluded
134
that accumulation of ORM is chiefly controlled by wave base, which is a function of
fetch and water depth. Thus, sediments within range of wave base have the potential of
being removed via resuspension during high energy storm events (Riggs and Ames,
2003). Due to the limitation of wave base, accommodation space in the AES appears to
be limited by sea level rise and basin subsidence. Regional rates of sea level rise from
tidal gages in Charleston, SC (1921-2000), Hampton, VA (1927-2000), and limited data
from Duck, NC (1980-2000) show sea level rising at rates of 0.31 cm yr ', 0.32 cm yr ',
and 0.46 cm yr"’, respectively (Riggs and Ames, 2003). The relationship between the
average accumulation rate for the AES, regional rates of sea level rise, and the below
predicted atmospheric inventory of ^'°Pb and '^^Cs indicate that accumulation of
sediments are responding to sea-level rise on the long term, but short term rates of
accumulation are influenced more so by wave base influence. Therefore, the average rate
of sediment accumulation in the AES appears to be influenced by short-term storm events
and long-term sea level rise and basin subsidence.
Oldfield et al. (1989) have shown that inventories of excess ^'®Pb in cores can be
used to assess net sediment flux in estuaries when the appropriate conditions are met (i.e.,
cores where grain-size or salinity are not causing desorbtion or an overall decrease in
activities). Cores from the AES were largely below predicted and indicate that there is a
net loss of sediments from the AES probably to the Pamlico Sound to the south. Based
on present data, the stations above predicted atmospheric excess Pb inventory are in
the protected reaches of the estuary (ALBOl SI, SL02S1, PASOl SI, ROAOl S4) where
sedimentation rates were highest, between 0.20 and 0.74 cm yr ' (see Figure 1.3, Table
135
4.8). Wells and Kim (1989) synthesized three decades of research in the Albemarle-
Pamlico estuarine system and hypothesized that little sediment escaped the AES and any
transport of sediment was restricted to local redistribution by currents and storm waves.
Data from this study and work by Corbett et al. (2004) in the Pamlico basin to the south
show this hypothesis to be inaccurate. Corbett et al. (2002) and Tulley et al. (2003)
provide evidence of ^'°Pb inventories in excess of that predicted for atmospheric
deposition in Pamlico Sound, suggesting that a secondary source of sediments is
contributing to the infilling of the basin. Thus, as is indicated by inventories in the AES
and those in the central basin of Pamlico Sound (Corbett et al., 2004), sediments are
being removed from the AES and transported through Croatan Sound into Pamlico Sound
where they are deposited into the deeper central basin. Wells and Kim (1989) and
Benninger and Wells (1993) conclude that relatively little sediment is lost through the
inlets to the open-ocean. They support a unidirectional transport mechanism for
sediments to the Pamlico Sound by periodic storm events (e.g., Nor’easters and
hurricanes) and high freshwater discharge from the rivers. Figure 5.1 shows a MODIS
Level-IB satellite image of eastern North Carolina (MODIS Image Gallery, 2003) and
the sounds one day after Hurricane Isabel made landfall (September 18, 2003) in eastern
North Carolina. The sediment plume is largely from shoreline erosion of Albemarle
Sound and Chowan River bluff sediments and shows the rapid eastward transport of the
sediment (Riggs and Ames, 2003).
Sedimentation rates in the AES were similar to many of the regional radionuclide
studies from the Neuse River (Benninger, 1990; Giffin and Corbett, 2003), and
136
Figure 5.1. Landsat 7 image provided by NASA of the eastern North Carolina on September 19, 2003 one
day after Hurricane Isabel passed directly over. Note sediment plume in Albemarle Sound is the result of
shoreline erosion of Chowan River bluff sediments by the category 2 hurricane and the minor amounts of
suspended sediment exiting through the inlets (MODIS Image Gallery, 2003).
137
Chesapeake Bay and its tributaries (Dellapenna et al., 1998; Dellapenna et al., 2003).
Studies in the Neuse River agree well with the results of this study, showing that
sediments are transported down-river unidirectionally toward Pamlico Sound and
deposited at rates between 0.14 and 0.55 cm yr ' (Benninger, 1990; Giffm and Corbett,
2003). Dellapenna et al. (1998) and Dellapenna et al. (2003) indicate that sediments are
accumulating at rates < 0.2 cm yr ' in the physically dominated tributary estuaries such
as the York River, which is nearly identical to results from this study. These results
along with those from regional estuaries suggest that sediments are accumulating at rates
slower than sea-level rise, and appear to be keeping pace with sea level rise and
exceeding it where accommodation space allows or storm events and physical processes
are less frequent and so resuspension and mobilization is less prevalent.
5.4 Historical Record - Paieoenvironmental Implications
Constructing a geochronology of sediments in the central Albemarle Sound using
the sedimentation rates developed for the cores yields a minimum estimate of 65 years of
sediment history preserved in ALB01S1C2, 320 years preserved in ALB01S3C2 and 350
years preserved in ALB01S4C2. In ALB01S1C2 two biofacies (inner estuarine and
estuarine) were recognized. The transition at 6 cm could be interpreted by one of the two
scenarios. Either the transition represents an abrupt shift seaward of the inner estuarine
biofacies in the early- to mid-1990’s or it could be an ephemeral layer of sediment eroded
from upstream. The former interpretation could have been caused by an increase in fresh
water inflow from the Chowan and Roanoke Rivers due to increased hurricane and
138
tropical storm activity impacting eastern North Carolina during the 1990’s (Riggs and
Ames, 2003). The latter interpretation is supported by the presence of two different
living species {Miliammina fusca and Ammotium salsum) above and below the biofacies
transition (see Table 4.10) and radionuclide data from Corbett et al. (2004). Corbett et al.
(2004) showed that this layer was possibly an ephemeral layer of sediment that fluctuated
in its thickness through the seasons, as sediment was deposited and then remobilized
away from the coring site. In ALBOl S3C2 and ALBOl S4C2 the effects of resuspension
make it difficult to assign a definitive geochronology to the cores. The base of
ALBOl S3C2 and ALBOl S4C2 date to the later half of the seventeenth century when the
AES was influenced by four inlets (Old Currituck, Musketo, Roanoke, and Gunt) (Figure
5.2) (Fisher, 1962). The presence of Elphidium excavatum at the base of ALBOl S3C2
shows that a calcareous fauna was present in the AES due to higher salinities supported
by the inlet openings north of the present Oregon Inlet.
In the early nineteenth century the last two inlets adjacent to the AES closed,
Roanoke Inlet in 1811 and New Currituck Inlet in 1828 (Dunbar, 1958). This time period
correlates with the 22-25 cm interval of ALBOl S3C2 and the 13-16 cm interval of
ALBOl S4C2. No Ammonia sp. organic linings were present in the basal interval of either
core, which could be due to taphonomic loss. However, their presence up-core extends
into sediments deposited after 1828, possibly a result of smearing by resuspension.
Stable isotope data from Letrick (2003), in cores taken from the same stations within the
AES indicated that isotopically “lighter” ô'^C values occurred farther inland than today;
similar values are now restricted to the eastern sounds. Thus, stable isotope data show
139
INLET NAMES
1 Old Currituck
2 New Currituck
3 Muskelo
4 Trinity Harbor
5 Caffey's
6 Roanoke
7 Gunl
8 Oregon
9 New
10 Loggerhead
11 ChickinacomnDOck
12 Chacandepeco
13 Halteras
14 Wells
15 Old Hatteras
16 Ocracoke
17 Whalebone
18 Swash
19 Sand Island
20 Drum
21 Cedar
22 South Core 1
23 Old Drum
24 South Core 2.
25 Barden
26 Beaufort
27 Bogue Banks 2.
28 Cheeseman
29 Bogue Banks 1.
30 Bogue
LEGEND
Figure 5.2. Map showing historic inlets and their geographic distribution through time along the Outer
Banks ofNorth Carolina (Dolan, 1985 after Fisher, 1962).
140
that the closing of the inlets contributed to a significant shift from a marine sourced ô'^C
to a terrestrial sourced ô'^C.
A modem analogue for the pre-1828 AES is Abbene et al.’s (2004) study of
Pamlico Sound. The present day southern portion of Pamlico Sound has salinities
averaging 22 and is dominated by a fauna characterized by the calcareous taxa Elphidium
excavatum and Ammonia parkinsoniana (Abbene et al., 2004). With the historic
presence of multiple inlets adjacent to the AES pre-1828 (Dunbar, 1958), it is likely that
similar environmental conditions persisted behind the Outer Banks at that time, as
indicated by the presence ofAmmonia sp. organic linings in ALBOl S3C2 and
ALBOl S4C2 and E. excavatum at the base of ALBOl S3C2. The range extension of
Elphidium excavatum and Ammonia parkinsoniana further west into the AES thus
depended on the proximity of the open inlets. The very limited data that can be gained
from ALBOlS3C2 and ALB01S4C2 suggest an early nineteenth century transition from
an estuarine system affected by more marine influence to a restricted estuarine system
dominated by oligohaline conditions; these latter conditions have persisted to the present
day.
CHAPTER 6
SUMMARY AND CONCLUSIONS
The foraminiferal distributions and sediments of the AES yield much insight into
the modem estuarine system, as well as to its recent past. Distributions of live and dead
foraminifera have enabled the characterization of benthic estuarine environments and
paleoenvironmental reconstruction of sediment cores. Radionuclide analysis of sediment
cores provided rates of sediment accumulation and a geochronology for age
interpretations of paleoenvironments. The rate of sediment accumulation in the AES is
limited by wave base and fetch in the short-term, and the rate of sea level rise and basin
subsidence over the long term as accommodation space for sediments is created.
The conclusions of this study are:
1. Distributions of foraminifera in the AES, both living and dead were influenced by
sediment type and salinity.
2. Thirty-seven species of foraminifera were recorded in the AES, 19 of which were
found living. Cluster analysis of foraminiferal surface samples from 49 stations using the
living populations and the dead assemblage distinguished similar biofacies. The living
biofacies characterized four environments: a mixed marsh and estuarine, nearshore
marine, estuarine, and estuarine shoal. The dead biofacies characterized five
environments: the nearshore marine and inlet, estuarine shoal, estuarine, inner estuarine.
and marsh.
142
3. The low numbers of biofacies recognized indicates that estuarine foraminiferal
distributions are broad and species tolerate wide variations of environmental conditions.
4. Comparison of relationships between the living and dead biofacies indicated that
several taphonomic processes (transport and mixing, dissolution, mechanical destruction)
were active, but with limited affects, on foraminiferal assemblages in the AES.
5. Radionuclide analysis of sediment dynamics in the AES indicated that the estuary had
an average accumulation rate of 0.13 cm yr ' (for stations which were not above predicted
atmospheric excess Pb inventory). Maximum rates of accumulation were in the
protected reaches of the estuary where inventories were above predicted atmospheric
deposition and accumulation rates ranged from 0.20 to 0.74 cm yr '.
6. Excess ^'®Pb inventory of sediment cores throughout the AES indicates that with the
exception of cores in protected reaches of the estuary (ALBOISI, SL02S1, PASOISI,
ROA01S4), there is a net deficit in predicted inventories. This suggests that sediments
are resuspended by wind-generated waves and currents and flushed from the system by
river discharge and wind-tides, probably to Pamlico Sound to the south.
7. Sediments in the AES are accumulating at rates less than the current rate of sea level
rise for this region, 0.32 to 0.46 cm yr', except in protected portions of the estuary. This
aides in supporting the conclusion that sediment accumulation in the AES is controlled
on the short-term by wave base in relation to storm events and the creation of
accommodation space by basin subsidence and sea level rise on the long-term.
8. Paleoenvironmental reconstruction of three short cores (ALB01S1C2, ALB01S3C2,
and ALB01S4C2) identified two biofacies (inner estuarine and estuarine) in the cores.
143
Both biofacies were present in ALB01S1C2 and only the estuarine biofacies was present
in the latter two cores. Paleoenvironmental changes in ALB01S1C2 indicated that this
portion of Albemarle Sound is influenced by ephemeral deposition of upstream sediments
indicative of the inner estuarine biofacies over central basin sediments characterized by
the estuarine biofacies or it has experienced an increase in freshwater influence since the
early 1990’s due to increased hurricane and storm activity. Paleoenvironmental changes
recorded in ALBOl S3C2 and ALBOl S4C2 were recognized by trends in rare calcareous
taxa {Ammonia sp. organic linings and Elphidium excavatum), which indicated that the
AES was under more marine influence prior to 1828 when several inlets north of the
present day Oregon Inlet provided a more direct connection with the Atlantic Ocean.
9. Modem foraminiferal assemblages and radionuclide tracers are useful tools in
distinguishing environmental changes in late Quaternary deposits of coastal North
Carolina and the adjacent region.
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SYSTEMATICS
Thirty-seven species-level taxa were distinguished in this study; only 31 of them
were identifiable to the species level and four to the genus level. Identifications were
made via comparison with the holotypes, paratypes, hypotypes, and unfigured specimens
lodged in the National Museum of Natural History, Smithsonian Institution, Washington,
D.C. Taxa are organized below following the classification of Loeblich and Tappan
(1988). Categories of relative abundance have been defined as: most abundant (>50%),
abundant (25 to 49%), common (5 to 24%), and rare (<5%). Salinity values were
grouped as follows, near-fresh (0-2 %o), low brackish (>2-10 %o), moderately brackish
(>10-18 %o), high brackish (>18-30 %o), and marine (>30 %o).
Order FORAMINIFERIDA Eichwald, 1830
Suborder TEXTULARIINA Delage and Hérouard, 1896
Superfamily ASTRORHIZACEA Brady, 1881
Family SACCAMMINIDAE Brady, 1884
Subfamily THURAMMININAE Miklukho-Maklay, 1963
Genus THURAMMINA Brady, 1879
Pseudothurammina limnetis Scott, Medioli, and Williamson
Plate 1, Figure 1
161
Armorella sphaerica Heron-Allen and Earland. - PHLEGER and WALTON, 1950, p.
211, pi. l,fig. 1.
Astrammina rara^JirimnhXcx. - ELLISON and NICHOLS, 1976, p. 141. - SCOTT,
1977, p. 166, pi. 2, figs. 1-3.
Astrammina sphaerica (Heron-Allen and Earland). - ZANINETTI et al., 1977,
p. 176, pi. 1, fig. 9.
ThuramminaÇ?) limnetis SCOTT and MEDIOLI, 1980a, p. 43, pi. 1, fig. 1-3.
Pseudothurammina limnetis SCOTT et al., 1981, p. 126.
Description. Test unilocular, round periphery; wall finely arenaceous, rough
texture, delicate, flexible; chamber inflated, round; variable number of irregular
mammillae; apertures occur at the ends of the mammillae.
Remarks. Specimens of this species compared very well with Scott and Medioli’s
(1980a) T. limnetis holotype (USNM #278127), paratypes (USNM #278128 and
#278129) and their hypotypes (USNM #414002) from Chebogue Harbour, Nova Scotia.
Scott and Medioli (1980a) doubtfully placed their species with Thurammina and later
assigned it to a new genus Pseudothurammina limnetis (Scott et al., 1981) largely
because Thurammina possesses no inner lining and it is a deepwater form rather than a
marsh species.
Occurrence. This species was found dead and was rare to common at two sites,
CUR01S2G1, a back-barrier marsh in the near-fresh to low brackish Currituck Sound and
CROOl S4G1, a mainland marsh with a moderate brackish salinity. Scott and Medioli
(1980a) noted that this species is restricted to the lower and middle marshes in Nova
162
Scotia.
Superfamily RZEHAKINACEA Cushman, 1933
Family RZEHAKINIDAE Cushman, 1933
Genus Miliammina Heron-Alien and Earland, 1930
Miliammina fusca (Brady)
Platel, Figure 2
Quinqueloculina fusca BRADY, 1870, p. 286, pi. 11, figs. 2, 3.
Miliammina fusca (Brady). - PARKER, 1952b, p. 452, pi. 2, figs. 6a, b. - MILLER,
1953, p. 51, pi. 7, fig. 10. -PARKER and ATHEARN, 1959, p. 340, pi. 50, figs.
11,12. - ELLISON and NICHOLS, 1970, p. 14, pi. 1, fig. 4.
Description. Test medium size; wall finely to coarsely arenaceous, composed of
coarse silt grains, white to a light orangish-brown; test elongate to elliptical,
quinqueloculine; chambers distinct, elongate, rounded periphery; sutures distinct,
depressed; aperture at end of last chamber, rounded or semilunate.
Remarks. This species compared well with specimens from Mason Inlet, North
Carolina (Miller, 1953) (USNM #627475) and Poponesset Bay, Massachusetts (Parker
and Atheam, 1959) (USNM #626389). It is distinguished from Miliammina petila in that
it is composed of coarser silt grains, as opposed to the somewhat smooth and off-white
test of M. petila.
Occurrence. The living distribution ofM. fusca was restricted to 19 (39 %) of 49
sites but it was abundant to most abundant at a majority of those sites. In the dead
163
assemblage M. fusca occurred at 37 (76 %) of 49 sites. Its dead proportions were rare to
common in samples throughout the estuarine system and were only abundant in some of
the marshes and at the head of the Albemarle Sound.
Miliammina petila Saunders
Plate 1, Figure 3, 4
Miliammina petila SAUNDERS, 1958, p. 88, pi. 1, fig. 15. -TODD and LOW, 1981, p.
15.
Description. Test small, delicate; very finely arenaceous, off-white with a shiny
luster, smooth; test is elliptical to elongate, round periphery, quinqueloculine; chambers
distinct; sutures distinct, depressed; aperture circular with a neck, terminal, centered over
end of test.
Remarks. This species compared well with the holotype (USNM #P5590) and
hypotype (USNM #P5591) of Saunder’s (1958). This species is distinguished from M.
fusca by its fragile, small, narrow, ovate to elliptical test with terminal circular aperture at
top center of test. M. fusca, in comparison, has coarser agglutinated particles.
Occurrence. Living specimens were restricted to the marsh where it was
common. Dead specimens ofM. petila were common to abundant in marsh
environments and were rare in waters along the estuarine shoreline.
Superfamily HORMOSINACEA Haeckel, 1894
Family HORMOSINIDAE Haeckel, 1894
164
Genus REOPHAX de Montfort, 1808
Reophax nana Rhumbler
Reophax nana RHUMBLER, 1911, p. 182, pi. 8, figs. 6-12. - PARKER, 1952b, p. 457,
pi. l,figs. 14, 15. - TODD and BRÔNN1MANN, 1957, p. 23, pi. l,fig. 17.
ELLISON and NICHOLS, 1970, p. 14, pi. 1, fig. 2. - SCOTT and MEDIOLI,
1980a, p. 43,pl. 2, fig. 6.
Description. Test uniserial, arcuate in form; wall arenaceous of medium
coarseness, composed of quartz sand grains; chambers barely distinct, increasing in size
gradually as added; sutures indistinct to slightly depressed; aperture terminal, small round
opening.
Remarks. The hypotypes of Ellison and Nichols (1970), Scott and Medioli
(1980a), and Parker (1952b) compared well with the few specimens present. It is
distinguished from Reophax sp. because chambers increase in size as added.
Occurrence. Reophax nana was not found living and occurred at two sites on the
southern tip of Roanoke Island in a marsh and in the adjacent shallow estuarine waters
and was rare.
Reophax sp. Parker and Atheam
Reophax sp. PARKER and ATHEARN, 1959, p. 339, pi. 50, fig. 1.
Description. Test uniserial, rectilinear; wall arenaceous, of medium coarseness;
chambers round, equal in size, slightly larger proloculus; sutures slightly depressed;
aperture round and terminal.
165
Remarks. Reophax sp. closely resembles the hypotype of Parker and Atheam
(1959). Broken tests are distinguished from Ammobaculites exiguas by their consistently
smaller test size.
Occurrence. This species was found living at one site along the back-barrier
shoreline, adjacent to Oregon Inlet (PAM01S8), where it was rare. Dead specimens were
rare along the southern tip of Roanoke Island (ROA01S4 and S5) and the adjacent
estuarine shoreline of the barrier island in the vicinity of Oregon Inlet (PAMOl S5 and
S8). Parker and Atheam (1959) recognized that this species is more abundant toward
higher salinities, though always rare, comprising no more than 2% of an assemblage.
This pattern was evident for this study area as well.
Superfamily LITUOLACEA de Blainville, 1827
Family HAPLOPHRAGMOIDIDAE Maync, 1952
Genus Haplophragmoides Cushman, 1910
Haplophragmoides bonplandi Todd and Bronnimann
Plate 1, Figure 5
Haplophragmoides bonplandi TODD and BRONNIMANN, 1957, p. 23, pi. 2, fig. 2. -
SCOTT and MEDIOLI, 1980a, p. 40, pi. 2, figs. 4, 5. - TODD and LOW, 1981,
p. 16.
Description. Wall fine to coarsely arenaceous, smooth in texture; test is
planispiral, periphery rounded; well developed open umbilicus, moderately to deeply
depressed; 5 to 7 chambers round, slightly lobate, inflated, increase significantly in size
166
as added; sutures are radial, deeply depressed; aperture is a low arch with a lip on the
apertura! face of last chamber.
Remarks. The holotype (CC #64612) and paratypes (USNM #370142) of Todd
and Bronnimannn (1957) compared very well with specimens from the marshes and
nearshore estuarine environment.
Occurrence. H. bonplandi was found living at one marsh site on the mainland in
Croatan Sound where it was common. Dead H. bonplandi specimens were common in
the marshes and were rare along the estuarine shoreline.
Haplophragmoides hancocki Cushman and McCulloch
Plate 1, Figure 6
Haplophragmoides hancocki CUSHMAN and McCULLOCH, 1939, p. 79, pi. 6, figs. 5,
6. - PARKER and ATHEARN, 1959, p. 339, pi. 50, figs. 2, 3. - ELLISON and
NICHOLS, 1970, p. 14, pi. 1, fig. 5. - TODD and LOW, 1981, p. 16.
Description. Wall finely arenaceous, smooth texture, planispiral, round
periphery; umbilicus moderately depressed, slightly open; chambers slightly inflated,
chambers increase slightly in size as added; sutures curved, depressed; aperture, semi-
circular to elongate arch at base of apertural face, lip protrudes over the top of the
aperture.
Remarks. This species compared well with the paratypes of Cushman and
McCulloch (1939). It is easily distinguished from the other Haplophragmoides species
by its sinuous sutures and characteristic protruding lip on apertural face.
167
Occurrence. H. hancocki was not found living, however, dead specimens were
found in marshes in Currituck Sound (CUR01S4) and Croatan Sound (CRO01S4) and
along the estuarine shoreline of southern Roanoke Sound (ROA01S5), where it was rare.
Haplophragmoides manilaensis Andersen
Plate 1, Figure 7, 8
Haplophragmoides manilaensis ANDERSEN, 1953, p. 22, pi. 4, figs. 8a, b. - TODD
and BRÓNNIMANN, 1957, p. 23, pi. 1, figs. 24-26. - SAUNDERS, 1957, p. 2,
pi. 1, figs. 1,2.- GROSSMAN and BENSON, 1967, p. 47, pi. 2, figs. 6, 7. -
ELLISON and NICHOLS, 1970, p. 14, pi. l,fig. - HAMAN, 1983, p. 71, pi. 3,
figs. 12, 13. - SCOTT et al., 1991, p. 385, pi. l,figs. 18, 19.
Description. Wall finely arenaceous, slightly roughened; test planispiral,
involute, round, lobate; umbilicus open, deeply depressed; chambers are inflated, increase
in size as added, forming a lobate periphery; sutures are straight, deeply depressed;
aperture is a low arch with a lip at base of apertural face.
Remarks. This species compared well with the hypotypes of Andersen (1953) and
his paratypes (USNM #370144). It also compared well with the hypotypes of Saunders
(1957), Grossman and Benson (1967), and Ellison and Nichols (1970).
Occurrence. No living specimens of H. manilaensis were found. H. manilaensis
was rare in the AES but was found in slightly higher abundance (3 to 6%) in fringe
marshes and <1% along the adjacent estuarine shoreline.
168
Haplophragmoides wilberti Andersen
Plate 1, Figure 9, 10
Haplophragmoides wilberti ANDERSEN, 1953, p. 21, pi. 4, figs. 7a, b. - TODD and
BRÓNNIMANN, 1957, p. 23, pi. 1, figs. 28, 29. - SAUNDERS, 1957, p. 3, pi. 2,
fig. 1. - GROSSMAN and BENSON, 1967, p. 47, pi. 2, figs. 12-14. - ELLISON
and NICHOLS, 1970, p. 14, pi. 1, fig. - HAMAN, 1983, p. 72, pi. 3, figs. 14-15.
- SCOTT et al., 1991, p. 385, pi. 1, figs. 18, 19.
Description. Wall very finely arenaceous, smooth; test planispiral, involute,
periphery rounded; umbilicus open, deeply depressed; chambers inflated, increase in size
as added; sutures are straight to gently curved; aperture a low arch with lip at base of last
chamber.
Remarks. Specimens of this species compared well with paratypes (USNM
#370149) of Andersen (1953). It is easily distinguished from other species of
Haplophragmoides by its polished test, flat apertural face, sinuous sutures, and round
periphery.
Occurrence. Dead H. wilberti were found in or near a marsh and was rare with a
maximum of 7% at ROAOl S7G1, a sandy beach adjacent to a marsh on the back-barrier
side of Roanoke Sound.
Genus TROCHAMMINITA Cushman and Bronnimann, 1948a
Trochamminita irregularis Cushman and Bronnimann
Trochamminita irregularis CUSHMAN and BRONNIMANN, 1948a, p. 17, pi. 4, figs. 1-
169
3. - SAUNDERS, 1957, p. 4, pi. 2, figs. 2-8. - TODD and BRÔNN1MANN,
1957, p. 30, pi. 4, figs. 19-22. - HAMAN, 1983, p. 72, pi. 4, figs. 1 -7.
Description. Test initially planispiral or slightly irregular planispiral in early
stages, then becoming quite irregular varying to different degrees in the adult stage; wall
finely arenaceous, smooth; chambers are inflated, increase in size rapidly in final whorl,
if an irregular stage is present, chambers vary in size and are added at random; sutures are
radial in the planispiral portion of the test and depressed throughout; multiple areal
apertures in the irregular portion and single to multiple in the planispiral portion with a
pronounced neck.
Remarks. Specimens compare very well with hypotypes of Cushman and
Bronnimann (1948a), Saunders (1957) (USNM #P5093 to P5099), and Haman (1983). It
is distinguished ifom Trochamminita salsa by its irregular later development of
chambers, whereas T. salsa is planispiral throughout with one or a few apertures in the
final chamber (Saunders, 1957).
Occurrence. Specimens of T. irregularis were rare and found dead at two sites,
one marsh site (CUR01S2) and one in an eroding runnel adjacent to a marsh in Currituck
Sound (CUR01S4).
Trochamminita salsa (Cushman and Bronnimann)
Plate 1, Figure 11
Labrospira salsa CUSHMAN and BRONNIMANN, 1948a, p. 16, pi. 3, figs. 5, 6.
Trochamminita salsa (Cushman and Bronnimann). - SAUNDERS, 1957, p. 6, pi. 1, figs.
170
3-8. - HAMAN, 1983, p. 72, pi. 4, figs. 8, 9. -HAYWARD and HOLLIS, 1994,
p. 206, pi. 2, figs. 12-14.
Description. Test planispiral, evolute, periphery lobate; open, deeply depressed
umbilicus, 6 to 7 chambers to a whorl, each chamber increasing in size, inflated, wall
finely arenaceous, smooth, polished; sutures straight, radial, slightly to deeply depressed;
single areal aperture on the lower half of the apertural face with a pronounced neck; in
juveniles aperture is closer to the equatorial margin, with a less pronounced neck.
Remarks. Specimens of this species compared well with hypotypes from
Saunders (1957) (USNM #P5100 to P5105) and the holotype (CC #56632) of Cushman
and Bronnimann (1948a). Most specimens possessed only one areal aperture which,
based on Saunder’s work, means that most specimens found were juvenile.
Occurrence. T. salsa was rare and not found living. It occurred at the same sites
as T. irregularis but in lesser abundance and at one site at the head of the Alligator River
(ALLOISI) in detrital rich sediment (abundance of 5%).
Family LITUOLIDAE de Blainville, 1827
Subfamily AMMOMARGINULININAE Podobina, 1978
Genus Ammobaculites Cushman, 1910
Ammobaculites crassus Warren
Plate 1, Figure 12
171
Ammobaculites crassus WARREN, 1957, p. 35, pi. 3, figs. 5, 6, 7. - ELLISON and
NICHOLS, 1970, p. 14, pi. 2, fig. 4. - GROSSMAN and BENSON, 1967, p. 49,
pi. 1, figs. 4, 5, 10.
Description. Test size large; wall coarsely to very coarsely arenaceous; coil
slightly evolute, tending toward trochoid, becomes uniserial in later portion; umbilicus
slightly depressed, closed; chambers generally increase in size as added, distinct, inflated,
ovate to rounded; sutures distinct, depressed, usually slightly curved and angled to the
interior, sutures parallel; aperture round, terminal, with a slight neck.
Remarks. The early planispiral portion is slightly inflated, but can be slightly
trochoid. The uniserial portion is rectilinear, but can also be non-rectilinear if chambers
increase in size as added. The chambers can be somewhat indistinct in the coil but are
very distinct in the uniserial portion. The degree of chamber inflation (rounded or ovate)
varies. The periphery can be slightly lobate in uniserial portion, but smooth in early
portion. Specimens most closely resemble the figured holotype and paratypes of Warren
(1957; pi. 3, figs. 5, 6, and 7). Ellison and Nichols (1970; pi. 2, fig. 4) and Grossman and
Benson (1967; pi. 1, figs. 4, 5, 10) illustrate another variant of^. crassus commonly
found in sandier environments. A. crassus is distinguished from A. subcatenulatus,
which is more robust; the coil ofA. subcatenulatus has no trochoid tendency and is much
more inflated throughout the entire test. A. crassus is distinguishable from Ammotium
salsum by its inflated early chambers in the coil as opposed to being compressed. The
rectilinear uniserial portion, does not uncoil from the early portion prematurely as in A.
salsum.
172
Occurrence. A. crassus is widely distributed in the sounds and embayed
tributaries. Live specimens occurred at 27 (55%) of the 49 sites and were abundant to
most abundant on sandy shoals and common throughout the remaining sample sites.
Dead specimens were found at 42 (86%) of the 49 sites and were most abundant on sandy
shoals located on the submerged perimeter platform of the estuary. A. crassus is the
dominant species that characterized the Estuarine Shoal Biofacies.
Ammobaculites dilatatus Cushman and Bronnimann
Plate 1, Figures 13
Ammobaculites dilatatus CUSHMAN and BRONNIMANN, 1948b, p.39, pi. 7, figs. 10,
11. - ELLISON and NICHOLS, 1970, p. 15, pi. 2, fig. 5. - PARKER and
ATHEARN, 1959, p. 340, pi. 50, figs. 4, 5.
Description. Test much compressed, medium to large in size; wall arenaceous,
fine to coarse; coil is evolute, later becoming uniserial; chambers not too distinct, not
inflated, two to three in uniserial portion; sutures indistinct, slightly depressed; aperture is
terminal, elongate, and narrow.
Remarks. AES specimens compare well with the holotype and paratype of
Cushman and Bronnimannn (1948b). Some specimens were rather large >lmm (back-
barrier nearshore flats) and composed of coarse sediment grains; these specimens
resembled Ammobaculites cf. A. dilatatus of Ellison and Nichols (1970; pi. 2, fig. 5). This
species is very distinct in that it is compressed throughout, possessed only a few
chambers in the uniserial portion, is rectilinear, and has an elongate, narrow aperture.
173
Occurrence. Living specimens ofA. dilatatus were rare on back-barrier shoals
and nearshore flats and near Oregon Inlet. Dead specimens were rare (averaging 2% of
an assemblage) and limited to the eastern half of the AES (23 sites).
Ammobaculites exiguus Cushman and Bronnimann
Plate 1, Figures 14
Ammobaculites exiguus CUSHMAN and BRONNIMANN, 1948b, p. 38, pi. 7, figs. 7, 8.
-ELLISON and NICHOLS, 1970, p. 15, pi. 2, figs. 7, 8.
Description. Test size small to medium; wall arenaceous, fine grained; early
portion evolute, later portion uniserial, uniserial portion either centered or just off-center
over coil, rectilinear; chambers inflated, indistinct in early portion and distinct in later
portion, round; sutures depressed, straight and horizontal in uniserial portion; umbilicus
slightly depressed; aperture terminal, round.
Remarks. Specimens of this species compare very well with the holotype and
paratypes of Cushman and Bronnimannn (1948b). This species is distinct from the other
species ofAmmobaculites by virtue of the unique location of the uniserial portion of the
test centered over the coil, as well as its straight (horizontal) sutures; chambers remain
the same size throughout the uniserial portion.
Occurrence. A. exiguus was rare (living and dead) in the back-barrier estuarine
environment of the AES mainly limited to Croatan, Roanoke, and northern Pamlico
Sound. It was found living at 5 (10%) of the 49 sites, all of which are adjacent to Oregon
174
Inlet on the back-barrier shoals, back-barrier nearshore flats, and back-barrier beaches.
Dead specimens were found at 11 sites also adjacent to Oregon Inlet.
Ammobaculites subcatenulatus Warren
Plate 1, Figures 15
Ammobaculites subcatenulatus WARREN, 1957, p. 32, pi. 3, figs. 11-13.
Description. Test size medium; wall coarsely arenaceous; coil is evolute
becoming uniserial after six chambers; umbilicus moderately depressed; chambers very
distinct in evolute and uniserial portions, inflated, rounded, all chambers near same size;
sutures are distinct, depressed, straight or maybe slightly oblique in uniserial portion;
aperture round, terminal, with a slight neck.
Remarks. This species has not been well documented in the literature. Specimens
in this study closely resemble the figured holotype and paratypes of Warren (1957; pi. 3,
figs. 11-13). This species differs from other Ammobaculites species in having inflated
chambers of the same size throughout.
Occurrence. The living population of subcatenulatus was abundant at marsh
sites in the Currituck (CUR01S4 and CUROISIO), and rare to common in the estuary
occurring at 5 ( 10%) of the 49 sites. The dead assemblage was abundant to most
abundant where it was associated with near-fresh brackish environments (near fresh
water inflow from rivers or marshes) and occurred at 21 (43%) of the 49 sites. It
exhibited a dramatic decline in abundance with increasing salinity. M fusca was
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common to abundant in the total assemblage simultaneously with the largest populations
of^. subcatenulatus.
Ammobaculites sp.
Description. Early portion coiled, evolute, then becoming uniserial; wall
arenaceous, of medium coarseness; chambers, not rectilinear in later portion, flaring
outward in an arcuate manner, early portion inflated, later portion more compressed;
sutures distinct, slightly depressed; aperture is a long narrow slit across the entire width
of the last chamber, terminal.
Remarks. This species was placed in Ammobaculites because it remained coiled
before transitioning into the uniserial portion.
Occurrence. One dead specimen was found near Oregon Inlet adjacent to a
back-barrier marsh (PAMOl S9).
Genus Ammotium Loeblich and Tappan, 1953
Ammotium salsum Cushman and Bronnimann
Plate 1, Figures 16
Ammobaculites salsus CUSHMAN and BRONNIMANN, 1948a, p.l6, pi. 3, fig. 7.
Ammotium salsum (Cushman and Bronnimann). - WARREN, 1957, p. 33. - PARKER
and ATHEARN, 1959, p. 340, pi. 50, figs. 6, 13. - GROSSMAN and BENSON,
1967, p. 49, pi. 2, figs. 1, 2, 8. - LEFURGEY, 1976, p. 241, pi. 22. - SCOTT
176
and MEDIOLI, 1980a, p. 37, pi. 1, fig. 11-13. - HAMAN, 1983,p. 87, pi. 5, figs.
6-9. - SCOTT et al., 1991, p. 384, pi. 1, figs. 11-13.
Description. Test small to large, compressed; wall finely arenaceous; early
portion evolute with a tendency to uncoil to varying degrees, becomes uniserial in later
portion, not rectilinear; umbilicus is slightly depressed to flush; chambers distinct, except
in early coiled portion, chambers increase in size as added, chambers slightly inflated to
varying degrees but still compressed, oval in cross-section; sutures are distinct in
uniserial portion, angled more progressively back to the interior margin as chambers are
added, depressed; aperture is terminal, round to oval, distinct, with slight neck.
Remarks. Specimens of this species compare well with the holotype (#56634)
and paratypes (#56742) of Cushman and Bronnimann (1948a). This species is
distinguished chiefly by its compressed nature, tendency to uncoil in the early portion,
increasing size of chambers, and sutures angle progressively more to the interior margin.
Occurrence. The living population ofA. salsum was abundant to most abundant
at 21 sites in the central portions of the North River and Albemarle, Currituck and
Croatan Sounds as well as northern Pamlico Sound in and adjacent to the back-barrier
marshes where salinities are at their highest in the AES (12-18%o). In this latter
environment, grains available for building the test are coarse making the test more robust
and inflated. A. salsum was common at 8 other sites including the shallow nearshore flats
of Roanoke and Croatan Sound and two ifinge marshes (CUROl S4 and ROAOl S5). The
dead assemblage was abundant to most abundant at 29 sites following the same pattern as
177
the living population. It was rare to common at another 10 sites from fringing marshes to
sandy nearshore flats.
Subfamily AMMOASTUTINAE Loeblich and Tappan, 1984
Genus AMMOASTUTA Cushman and Bronnimann, 1948a
Ammoastuta inepta Cushman and McCulloch
Plate 2, Figure 1
Ammoastuta ineptus CUSHMAN and McCULLOCH, 1939, p. 89, pi. 7, fig. 6.
Ammoastuta inepta (Cushman and McCulloch). - PARKER et al., 1953, p. 4, pi. 1, fig.
12. - TODD and BRONNIMANN, 1957, p. 23. - AKERS, 1971, p. 157, pi. 1,
fig. 3. - SCOTT et al., 1991, p. 384, pi. 1, fig. 15.
Ammoastuta salsa CUSHMAN and BRONNIMANN, 1948a, p. 17, pi. 3, figs. 14-16.
- ELLISON and NICHOLS, 1970, p. 15, pi. 2, fig. 3. - WARREN, 1957, p. 32.
Description. Test medium, compressed; wall finely to coarsely arenaceous,
smooth to rough; tight initial coil, then becoming uniserial, with a few small rectilinear
elongate chambers that increase in length as added until adult chambers extend about half
the periphery of the specimen; number of chambers varies from a few to 12; sutures are
distinct, slightly depressed; primary aperture is areal, a transverse slit in the middle of the
apertural face, pores at the bulging end (initial coil) function as supplementary apertures.
Remarks. Specimens with coarser grained and larger tests have often been called
A. salsa. A. salsa is considered here as a junior synonym ofA. inepta.
Occurrence. A. inepta was found living at only one site in a fringing marsh
178
adjacent to Croatan Sound, CRO01S4, where it is abundant, making up 35% of the living
population. Dead specimens of^. inepta were found at two marsh sites, CRO01S4 and
CUR01S2, where they were eommon and abundant. A. inepta was rare in the adjacent
estuarine waters and in other estuarine environments throughout the AES. The
abundance ofA. inepta decreases toward Oregon Inlet where it is not found in any of the
marshes or in the adjacent nearshore flats, suggesting a possible negative correlation with
increasing salinity.
Superfamily TROCHAMMINACEA Schwager, 1877
Family TROCHAMMINIDAE Sehwager, 1877
Subfamily TROCHAMMININAE Schwager, 1877
Genus TROCHAMMfNA Parker and Jones, 1859
Trochammina in/lata (Montagu)
Plate 2, Figure 3, 6
Nautilus inflatus Montagu, 1808, p. 81, pi. 18, fig. 3.
Rotalina inflata (Montagu). - WILLIAMSON, 1858, p. 50, pi. 4, figs. 93, 94.
Trochammina inflata (Montagu). - PARKER and JONES, 1859, p. 347. - PARKER,
1952b, p. 459, pi. 3, figs. 12, b. - PARKER and ATHEARN, 1959, p. 341, pi. 50,
figs. 18-20. - ELLISON and NICHOLS, 1970, p. 16, pi. 1, figs. 8, 9. -SCOTT
and MEDIOLI, 1980a, p. 44, pi. 3, figs. 12-14, pi. 4, figs. 1-3.
Description. Wall finely arenaceous, smooth surfaee; test planispiral, semi-lobate
periphery, rounded; umbilicus open, deeply depressed; 5 to 6 chambers in last whorl.
179
increase in size gradually, inflated; sutures distinct, slightly depressed, straight; aperture
is a small arched slit at the base of the last chamber on the ventral side.
Remarks. Specimens of this species matched well the hypotypes of Scott and
Medioli (1980a) and Parker and Atheam (1959).
Occurrence. Living specimens of T. inflata were found at one site (ROA01S5), a
Juncus marsh on the south side of Roanoke Island, where they comprised 7% of the
population. Dead specimens were rare to common (6% maximum) in the fringing
marshes of Roanoke and Croatan Sound and rare in the adjacent nearshore estuarine
waters.
Trochammina compacta Parker
Trochammina compacta PARKER, 1952b, p. 458, pi. 2, figs. 13a, b, 14a, b, 15a, b.
- BUZAS, 1965, p. 57. - TODD and LOW, 1981, p. 18.
Description. Test medium, concavo-convex, high trochoid spire which is broad
and round, compact, periphery round to slightly lobate; wall finely arenaceous, composed
of sand grains, semi-smooth; umbilicus moderately depressed; chambers inflated,
rounded, usually 3 to 4 in last whorl but 3 is most common; spiral sutures, distinct,
curved; aperture a narrow arched opening at the base of last chamber.
Remarks. This species matched very well with the holotype (USNM #312101)
and paratypes (USNM #312102, 312103, 421094) of Parker (1952b) from the Buzzards
Bay area of Long Island Sound. AES specimens tend to be larger than Parker’s.
180
Occurrence. T. compacta was found dead (<1 % of the assemblage) at a fringing
marsh on the southern end of Roanoke Island (ROA01S5) and in very shallow water near
a back-barrier fringing marsh of Bodie Island (PAMOl S5).
Trochammina lobata Cushman
Trochammina lobata CUSHMAN, 1944, p. 18, pi. 2, fig. 10. - PARKER, 1952b, p. 459,
pi. 3, figs, 2a, b. - SCOTT et al., 1977, p. 1580, pi. 4, fig. 1,2.
Description. Test medium, trochospiral, with lobate periphery, wall fine to
medium coarseness, smooth; umbilicus deeply depressed, narrow; chambers inflated,
rounded, increase in size as added, 7 visible ventrally; sutures deeply depressed, mostly
straight; aperture is an interio-marginal slit on the ventral side of the last chamber
extending into the umbilicus.
Remarks. This specimen was similar to Cushman’s (1944) holotype, but the
periphery was more rounded. It compared very well with the hypotypes of Parker
(1952b) and Scott et al. (1977).
Occurrence. Only one dead specimen was found adjacent to a marsh in shallow
estuarine waters at site PAMOl S5. This site was characterized by one of the most
diverse estuarine assemblages.
Trochammina ‘‘‘‘squamata'’''
Trochammina squamata PHLEGER and WALTON, 1950, p. 281. pi. 2, figs. 12, 13.
- ELLISON and NICHOLS, 1970, p. 16, pi. l,figs. 12, 13. - SCOTT and
181
MEDIOLl, 1980a, p. 45, pi. 4, figs. 6, 7. (not T. squamata Jones and Parker,
1860).
Description. Test small, trochospiral, round periphery, wall finely arenaceous,
acute periphery, concavo-convex with concave ventral side and dorsal convex side;
umbilicus deeply depressed; chambers distinct, compressed, seven chambers in last
whorl; sutures distinct, depressed, and sinuous; extra-umbilical aperture.
Remarks. T squamata of Jones and Parker (1860) was described as having four
chambers visible on the ventral side with the last chamber occupying from a quarter to a
half of the ventral side. This does not resemble specimens from this study. This study’s
T. “'‘'squamata" more closely resemble Phleger and Walton’s (1950) hypotype of
TrocJiammina squamata. Many other authors have also used this binomen for this
morphospecies.
Occurrence. This species only occurred at one site (PAMOl S2) where one dead
specimen was found.
Subfamily ROTALIAMMININAE Saidova, 1981
Genus SIPHOTROCHAMMINA Saunders, 1957
Siphotrochammina lobata Saunders
Plate 2, Figure 4, 5
Siphotrochammina lobata SAUNDERS, 1957, p. 9, pi. 3, figs. 1,2.- AKERS, 1971, p.
160, pi. 3, fig. 1.
182
Description. Test, trochospiral, with lobate periphery, dorsal side convex, ventral
side slightly concave; wall finely arenaceous, smooth, polished; chambers increase in size
as added, more inflated ventrally than dorsally, the last chamber forms a siphon-like lobe
that extends partially or fully into the umbilicus; sutures deeply depressed, straight to
sinuous; aperture at the umbilical end of the ventral lobe, circular, forward-directed.
Remarks. Specimens of this species matched very well with the holotype (USNM
#P5107) and paratypes (USNM #P5108) of Saunders (1957). This species is
distinguished irom T. inflate in that it has a circular aperture at the umbilical end of a
ventral lobe of the last chamber.
Occurrence. S. lobata was found dead and rare (<0.5%) at two marshes and three
nearshore estuarine environments of varying brackish salinities.
Genus TIPHOTROCHA Saunders, 1957
Tiphotrocha comprimata (Cushman and Bronnimann)
Plate 2, Figure 7, 8
Trochammina comprimata CUSHMAN and BRONNIMANN, 1948b, p. 41, pi. 8, figs. 1-
3.
Tiphotrocha comprimata (Cushman and Bronnimann). - SAUNDERS, 1957, p. 11, pi. 4
figs. 1-4. - PARKER and ATHEARN, 1959, p. 341, pi. 50, figs. 14-17.
- GROSSMAN and BENSON, 1967, p. 50, pi. 6, figs. 1-5. - ELLISON and
NICHOLS, 1970, p. 14, pi. 1, figs. 14, 15. - SCOTT and MEDIOLl, 1980a, p.
183
44, pi. 5, figs. 1-3. - SCOTT et al., 1991, p. 388, pi. 2, figs 5, 6. - CULVER et
al., 1996, p. 486, fig. 8.16, 8.17.
Description. Test trochospiral, compressed, with an irregular lobate periphery, concavo-
convex, dorsal side slightly convex, ventral side concave; wall finely arenaceous,
composed of fine sand grains, fairly smooth; chambers slightly inflated, only four to five
chambers visible ventrally, last chamber T-shaped and varies in degree of development,
chambers in early whorls increase in size regularly, but final chambers can be irregular in
size; sutures slightly depressed dorsally, curved, but degree of curvature increases in later
whorls; ventrally sutures are more depressed toward the umbilicus; aperture situated at
the umbilical end of the chambers in the last whorl.
Remarks. This species compared well with the holotype (USNM #56787) and
paratypes (USNM #56788, 56789) of Cushman and Bronnimann (1948b), as well as the
hypotypes (USNM #P5109a, P5109b, P5110, P5112) of Saunders (1957).
Occurrence. Only one live specimen of T. comprimata was found at the head of
the Pasquotank River (PASOlSI). Dead specimens were mostly found in rare abundance
in the eastern portion of the AES in the marshes fringing Currituck, Croatan, and
Roanoke Sounds, and in the nearshore estuarine environment.
Genus JADAMMfNA Bartenstein and Brand, 1938
Jadammina macrescens (Brady)
Plate 2, Figure 9
184
Trochammina inflata (Montagu) var. macrescens BRADY, 1870, p. 290, pi. 11, figs.
5 a-c.
Trochammina macrescens (Brady). - PARKER, 1952a, p. 408, pi. 4, figs. 8a, b. -
PARKER, 1952b, p. 460, pi. 3, figs. 3a, b. - PARKER and ATHEARN, 1959, p.
341, pi. 50., figs. 23-25. - GROSSMAN and BENSON, 1967, p. 50, pi. 5, fig. 8.
- ELLISON and NICHOLS, 1970, p. 16, pi. 1, figs. 10, 11. - SCOTT and
MEDIOLI, 1980a, p. 44, pi. 3, figs. 1-8. -TODD and LOW, 1981, p. 17.
Jadammina macrescens (Brady). -MURRAY, 1971, p. 41, pi. 13, figs. 1-5. -
MURRAY, 1979, p. 28, figs. 6 k-m.
Description. Test trochospiral, very compressed, periphery can be rounded to
slightly lobate, brown color; wall very finely arenaceous, smooth surface; umbilicus
slightly depressed, closed; chambers distinct, increasing in size as added, compressed to
slightly inflated, all chambers usually visible on dorsal side and only last whorl visible
ventrally; sutures distinct, slightly depressed, curved; aperture is a low arched slit at the
base of the last chamber on the ventral side.
Remarks. Specimens of this species compared very well to the hypotypes of
Parker and Atheam (1959) (USNM #626406 to 626408) and Scott and Medioli (1980a)
(USNM #414006).
Occurrence. Live specimens ofJ. macrescens were rare to common (4-12%) at
two marsh sites, one on the back-barrier side of Currituck Sound (CUR01S4) and one on
the mainland side of Croatan Sound (CROOl S4) near Spencer Creek. Dead specimens
185
were common to rare throughout the marshes sampled, but rare in the adjacent nearshore
estuarine waters.
Subfamily ARENOPARRELLINAE Saidova, 1981
Genus ARENOPARRELLA Andersen, 1951
Arenoparrella mexicana (Komfeld)
Plate 2, Figure 10, 11
Trochammina inflata (Montagu) var. mexicana KORNFELD, 1931, p. 86, pi. 13, figs.
5 a-c.
Arenoparrella mexicana (Komfeld). — SAUNDERS, 1957, p. 13, pi. 4, fig. 5. -
LOEBLICH and TAPPAN, 1988, p. 126, pi. 134, figs. 5-10. - PARKER and
ATHEARN, 1959, p. 340, pi. 50, figs. 8-10. - GROSSMAN and BENSON,
1967, p. 50, pi. 6, figs. 2-4. - ELLISON and NICHOLS, 1970, p. 15, pi. 2, fig. 1, 2.
Description. Wall very finely arenaceous, smooth surface, polished; test has
round periphery, trochospiral; chambers inflated, increase in size as added; sutures
distinct, slightly depressed, radial; aperture is usually a curved slit that extends up the
apertural face and/or a series of round areal apertures; supplementary openings are
usually present at the apex of the last chamber.
Remarks. This species compares very well with the hypotypes (USNM #626377
to 626379) of Parker and Atheam (1959) and Komfeld’s specimen in the Cushman
Collection (#59360).
186
Occurrence. Only two marsh sites, CRO01S4 and ROA01S5, contained living
specimens ofA. mexicana in common abundance (9-15%). Dead specimens ofA.
mexicana were rare and occurred at all the nearshore estuarine sites and three mid-
channel sites along the Alligator River.
Suborder ROTALIINA Delage and Hérouard, 1896
Superfamily CHILOSTOMELLACEA Brady, 1881
Family GAVELINELLIDAE Hofker, 1956
Subfamily GAVELINELLINAE Hofker, 1956
Genus HANZAWAIA Asano, 1944
Hanzawaia strattoni (Applin)
Plate 3, Figure 1
Truncatulina americana Cushman var. strattoni APPLIN in APPLIN et al., 1925, p. 99,
pi. 3, fig. 8.
Cibicides americana Cushman var. strattoni (Applin). - KORNFELD, 1931, p. 82.
Hanzawaia strattoni (Applin). - BANDY, 1954, p. 136, pi. 31, fig. 4. - TODD and
BRÔNNIMANNN, 1957, p. 41, pi. 12, fig. 16.
Description. Test planispiral, tending toward biconvex, convex dorsal side
involute, flattened ventral side slightly evolute due to umbilical apertural flaps covering
spire, rounded periphery; wall calcareous, coarsely perforate, nonperforate along
umbilical flaps and sutures; umbilicus is a narrow circular opening; chambers are many,
not very pronounced, increase in size gradually, umbilical apertural flaps from each
187
chamber overlap the preceding chamber forming supplementary openings along the
umbilical margin; sutures thickened, curved back to the periphery; primary aperture not
preserved due to broken final chambers.
Remarks. This species most closely resembles the hypotype (USNM 547586) of
Bandy (1954) in general morphology, but it tacks the supplementary openings along the
umbilical margin. Specimens most closely resemble Schnitker’s (1971; pi. 10, fig. 13)
Hanzawaia concéntrica. However, H. strattoni is distinguished from H. concéntrica in
that the former has a rounded axial periphery (tending to be biconvex) whereas the latter
has an angled axial periphery (planoconvex).
Occurrence. This species occurred at three sites in the Atlantic Ocean, one on the
inner shelf, 1.5 miles offshore of Oregon Inlet and two on the foreshore (one dead at each
site).
Family COLEITIDAE Loeblich and Tappan, 1984
Genus BUCCELLA Anderson, 1952
Buccella frigida (Cushman)
Plate 3, Figure 2
Pulvinulina frigida CUSHMAN, 1922, p. 144.
Eponides frigida (Cushman). — CUSHMAN, 1931, p. 45.
Buccella frigida (Cushman). - ANDERSON, 1952, p. 144, figs. 4-6.
Description. Test trochospiral, planoconvex, dorsally evolute and flat, ventrally
involute, round equatorial and axial periphery; wall calcareous; umbilical region open.
188
deeply depressed, covered by pustules which are present along the sutures and on the
earlier chambers, chambers come to a rounded point at umbilicus; sutures radial,
depressed and wide ventrally, slightly depressed dorsally and curved to periphery;
aperture interio-marginal, mid-way along the ventral side of the last chamber.
Remarks. The specimen compared well with Anderson’s (1952) figured
specimens at the Smithsonian Institution.
Occurrence. The figured specimen was the only one found of its genus and
species in the study area. It occurred at the ebb tide delta of Oregon Inlet.
Superfamily ROTALIACEA Ehrenberg, 1839
Family ROTALIIDAE Ehrenberg, 1839
Subfamily AMMONIA Saidova, 1981
Genus AMMONIA Briinnich, 1772
Ammoniaparkinsoniana (d’Orbigny)
Plate 3, Figure 3, 4
Rosalina parkinsoniana D’ORBIGNY, 1839, p. 99, pi. 4, figs. 25-21.
Rotalia beccarii (Linné) war. parkinsoniana (d’Orbigny). - PHLEGER and PARKER,
1951, p. 23, pi. 12, fig. 6.
Ammonia parkinsoniana (d’Orbigny) forma typica POAG, 1978, p. 397, 400-402, pi. 1,
figs. 5, 6, 8, 9, 13, 15, 19,21. -POAG, 1981, p. 38, pi. 45, fig. 1, pi. 46, figs.
1 a-b.
Ammonia beccarii (Linné). - ELLISON and NICHOLS, 1970, p. 15, pi. 2, figs. 9, 10.
189
- SCOTT and MEDIOLI, 1980a, p. 35, figs. 8, 9. - SCHNITKER, 1971, p. 193,
pl. 7, figs. la-c. - CULVER et al., 1996, p. 486, fig. 10.8, 10.9
Ammonia parkinsoniana (d’Orbigny). - LOEBLICH and TAPPAN, 1994, p. 165, pl.
368, figs. 7-9, 11, 13-16.
Description. Test trochospiral, biconvex, dorsally evolute, ventrally involute,
equatorial periphery rounded; wall calcareous, finely perforate; umbilicus deeply
depressed, composed on one or multiple bosses; 7 to 8 chambers in final whorl, inflated
and rounded, umbilical chambers come to a point at umbilicus; sutures dorsally slightly
raised to flush, ventrally more deeply depressed and widen toward the umbilicus;
aperture a low arch at the base of the last chamber on the ventral side.
Remarks. This species is nearly identical to Ammonia beccarii hypotypes of
Ellison and Nichols (1970) and Scott and Medioli (1980a), and compares very well with
A. parkinsoniana hypotypes (USNM #471501,471503) of Loeblich and Tappan (1994)
and Poag (1978) (USNM #254430, 254432, 254433).
Occurrence. Living specimens ofA. parkinsoniana were found at one site
(PAM01S5) in very shallow estuarine water near a back-barrier marsh at the south end of
Bodie Island. It occurred with 17 other species, where it made up 29% of the living
population and 5% of the dead assemblage. It occurred with the only living population of
Elphidium galvestonense in the AES. A. parkinsoniana was found dead and was rare (1-
5%) in normal salinity conditions of the foreshore and Oregon Inlet’s ebb tide delta.
190
Ammonia tepida {Cushman)
Plate 3, Figure 5
Rotalia beccarii Linnaeus var. tepida CUSHMAN, 1926, p. 79, pi. 1. - PARKER,
1952b, p. 457-458, pi. 5, fig. 8.
Rotalia beccarii (Linné) variants. - PARKER, 1954, p. 531, pi. 10, figs. 1, 2, 5, 6.
Ammonia beccarii tepida (Cushman). - ELLISON and NICHOLS, 1970, p. 15, pi. 2, fig.
11, 12.
Streblus beccarii (Linné) var. tepida ( Cushman). - TODD and BRÔNN1MANNN,
1957, p. 38, figs. 5-10.
Ammonia parkinsoniana (d’Orbigny) forma tepida POAG, 1978, p. 397, 400-402, pi. 1,
figs. 3, 4, 11, 12, 18. - POAG, 1981, p. 38, pi. 45, fig. 2, pi. 46, figs. 2 a-b.
Ammonia tepida (Cushman). - GROSSMAN and BENSON, 1967, p. 56, pi. 9, fig. 5, 9.
- LOEBLICH and TAPPAN, 1994, p. 166, pi. 371, figs. 5-10.
Description. Test trochospiral, biconvex, dorsally evolute, ventrally involute,
slightly lobate equatorial periphery; wall calcareous, finely perforate; umbilicus deeply
depressed, open, covered by very small pustules that extend up the sutures; inflated
chambers, 6 to 8 in final whorl, umbilical chambers come to a point at the umbilicus;
sutures are deeply depressed ventrally, widening toward umbilicus, slightly depressed
dorsally; aperture an arch in the lower apertural face.
Remarks. This species compares very well to hypotypes (USNM #304440,
304441) of Poag (1981) and to thehypotype of Ellison and Nichols (1970) as well as to
the holotype (CC #3143) of Rotalia beccarii Linnaeus var. tepida of Cushman (1926).
191
Occurrence. A. tepida was found dead at the inner shelf site (OFFOISI) and was
rare (2%).
Ammonia sp.
Description. Organic lining only, periphery lobate, finely perforate, exceptionally
preserved; six to seven inflated chambers visible ventrally, chambers rounded; dorsally
chambers are slightly inflated; open, deeply depressed umbilicus; sutures are deeply
depressed ventrally, widening toward the umbilicus, dorsally sutures slightly depressed;
aperture low arch at the base of the last chamber on the ventral side.
Remarks. The calcareous test is dissolved away. Specimens were grouped with
Ammonia due to the number of chambers in the last whorl (always one or two more than
T. inflata), the deeply depressed and open umbilical area, and the widening sutures
toward the umbilicus.
Occurrence. Living specimens occurred only in close proximity to Oregon Inlet,
including the extreme southern ends of Croatan and Roanoke Sounds where salinities
ranged from 10 to 18 %o. Dead specimens were rare to common near Oregon Inlet and
rare away from the inlet at the mouth of Albemarle and Currituck Sounds and the mouth
of the North, Pasquotank, and Alligator Rivers.
Family ELPHIDIIDAE Galloway, 1933
Subfamily ELPHIDIINAE Galloway, 1933
Genus ELPHIDIUM de Montfort, 1808
192
Elphidium excavatum (Terquem)
Plate 3, Figure 6
Polystomella excavata TERQUEM, 1875, p. 20, pi. 2, figs. 2 a-b.
Elphidium excavatum (Terquem). - PARKER, 1952a, p. 412, pi. 5, fig. 8. - PARKER,
1952b, p. 448, pi. 3, fig. 13. - BUZAS and SEVERIN, 1982, p. 37, pi. 8, fig. 2. -
BUZAS et al., 1985, p. 1083, 1084, figs. 6.7-6.10, 7.1, 7.2. - CULVER et al.,
1996, p. 486, fig. 10.11, 10.12.
Elphidium clavatum Cushman. -RONAI, 1955, p. 146, pl. 21, fig. 7. - GROSSMAN
and BENSON, 1967, p. 58, pl. 8, fig. 13-14. -ELLISON and NICHOLS, 1970, p.
16, pl. 2, figs. 7, 8. -KRAFT and MARGULES, 1971, p.251, fig. 17. - SEN
GUPTA, 1971, p. 89, pl. 2, figs. 28, 29. -SCHNITKER, 1971, p. 198, pl. 7, fig.
5.
Description. Test planispiral, involute, rounded equatorial periphery, ovate axial
periphery; wall calcareous, finely perforate, translucent to opaque white to light-brown;
flush to slightly raised umbilical boss or bosses; eight to ten chambers, slightly inflated;
sutures curved, become more tangential toward periphery, slightly depressed toward the
umbilical area, irregular sutural bridge placement, bridges become more prevalent with
addition of chambers; aperture is a row of small circular openings along the base of the
last chamber.
Remarks. This species matches very well with the hypotype (USNM #365944) of
Buzas et al. (1985) and the holotype (CC #10403) of E. clavatum Cushman and the
topotype (USNM #365943) of E. excavatum (Terquem).
193
Occurrence. The living population of E. excavatum consisted of one specimen
from the foreshore (BEAOISI) and one from the ebb tide delta of Oregon Inlet
(EBBOlSI). Both were the only living species at both sites. E. excavatum was most
abundant in the dead assemblage along the foreshore, inner shelf, and Oregon Inlet. One
specimen E. excavatum was found in the 40-42 cm interval of ALB01S3C2.
Elphidium galvestonense Komfeld
Plate 3, Figure 7
Elphidium gunteri COLE var. galvestonensis KORNFELD, 1931, p. 87, pi. 15, fig. 1.
Elphidium galvestonense KORNFELD. — PARKER et al., 1953, p. 7, pi. 3, figs. 15, 16.
- MILLER, 1953, p. 55, pi. 9, fig. 7. - PARKER and ATHEARN, 1959, p. 342,
pi. 50, figs 33-35. - GROSSMAN and BENSON, 1967, p. 60, pi. 7, figs. 1-2. -
ELLISON and NICHOLS, 1970, p. 16, fig. 9.3. - POAG, 1978, p. 403-404, pi. 3,
fig. 12. - BUZAS and SEVERIN, 1982, p. 37, pl.8, fig. 3.
Description. Test planispiral, round equatorial periphery, biconvex; wall
is calcareous, polished white when not etched; umbilicus has a flush to slightly
raised plug; 13 or more chambers; sutures deeply depressed, curved, with widely
spaced sutural bridges which give the sutures a pitted effect; aperture is a series of
circular openings above and along the base of the apertural face.
Remarks. This species compares very well with the hypotype (USNM #310200)
of Buzas and Severin (1982) and hypotypes (USNM #254840, 254841) of Poag (1981).
Occurrence. One estuarine site, PAMOl S5, possessed the only two specimens of
194
this species in the study area. Both were living and comprised 1% of the living
population and 0.6% of the total assemblage.
Elphidium subarcticum Cushman
Plate 3, Figure 8
Elphidium subarcticum CUSHMAN, 1944, p. 27, pi. 3, fig. 34-35. -PARKER, 1952a, p.
412, pi. 5, fig. 9. - GROSSMAN and BENSON, 1967, p. 60, pi. 7, figs. 3, 6. -
SCHNITKER, 1971, p. 198, pi. 7, fig. 3. - SEN GUPTA, 1971, p. 89, pi. 2, figs.
30, 31. - BUZAS et al., 1985, p. 1087, figs. 8.1, 8.2.
Description. Test planispiral, equatorial periphery rounded, ovate axial periphery,
specimens small; wall calcareous, opaque white, usually etched; umbilicus flush, covered
by small pustules; chambers, 8 to 9, slightly inflated; pustules line the suture, sutures
depressed, wide, possess small pits regularly spaced down the middle of the suture;
aperture style undetermined due to lack of specimens with unbroken final chambers.
Remarks. This species compares very well with the holotype (CC #40995) of E.
subarcticum Cushman, the pleisiotype (USNM #381458) of Parker (1948) and the
hypotype (USNM #281461) of Phleger (1952).
Occurrence. One site along the foreshore (BEAOl S2) and inside Oregon Inlet
(INSOl S1 ) possessed dead specimens of E. subarcticum. Specimens were common on
the foreshore and rare at Oregon Inlet.
195
Elphidium sp.
Plate 3, Figure 9
Description. Test small, finely perforate, rounded periphery; wall calcareous; 11
to 12 chambers, become more distinct as chambers are added; umbilicus is partially
covered by pustules and what appear to be rudimentary bosses; sutures more distinct and
depressed as chambers are added, no sutural bridges; aperture a row of four openings
along the base of last chamber.
Remarks. This specimen is very similar to specimens of E. excavatum except for
its lack of sutural bridges.
Occurrence. Elphidium sp. is represented by one dead specimen from Oregon
InletatINSOlSl.
PLATE 1
(bar = 100 )im)
1 Pseudothurammina limnetis Scott, Medioli, and Williamson; side
view
2 Miliammina fusca (Brady); side view
3,4 Miliammina petila Saunders; side view and apertural view
5 Haplophragmoides bonplandi Todd and Bronniman; side view
6 Haplophragmoides hancocki Cushman and McCulloch; side view
7,8 Haplophragmoides manilaensis Andersen; side view and apertural
view
9, 10 Haplophragmoides wilberti Andersen; side view and apertural view
11 Trochamminita salsa (Cushman and Bronniman); side view
12 Ammobaculites crassus Warren; side view
13 Ammobaculites dilatatus (Cushman and Bronniman); side view
14 Ammobaculites exiguus Cushman and Bronniman; side view
15 Ammobaculites subcatenulatus Warren; side view
16 Ammotium salsum Cushman and Bronniman; side view
 
198
PLATE 2
(bar = 100 iim)
Figures
1,2 Ammoastuta inepta Cushman and McCulloch; side view (fine-
grained) and side view (coarse-grained)
3,6 Trochammina inflata (Montague); dorsal view and ventral view
4,5 Siphotrochammina lobata Saunders; dorsal view and ventral view
7,8 Tiphotrocha comprimata (Cushman and Bronniman); dorsal view and
ventral view
9 Jadammina macrescens (Brady); ventral view
10, 11 Arenoparrella mexicana (Komfeld); dorsal view and ventral view
 
200
PLATE 3
(bar = 100 fim)
Figures
1 Hanzawaia strattoni (Applin); ventral view
2 Buccella frígida (Cushman); ventral view
3, 4 Ammonia parkinsoniana (d’Orbigny); dorsal view and ventral view
5 Ammonia tepida (Cushman); dorsal view
6 Elphidium excavatum (Terquem); side view
7 Elphidium galvestonense Komfeld; side view
8 Elphidium subarcticum Cushman; side view
9 Elphidium sp.; side view
 
Appendix A. Numbers of live specimens per sample, total number picked, fraction
picked, and specimens per 50 cm^.
203
Name BEAOISIGI BEA0IS2GI BEAOIS3GI INSOISIGI EBBOISIGl OFFOISIGI
No. of Living Specimens Picked 1 0 0 0 2 0
Fraction Picked I/I I/I I/I 1/2 1/1 I/I
Calc. Specimens per 50 cm' 1 0 0 0 2 0
Ammoasluta inepta 0 0 0 0 0 0
AmmobacuHtes crassus 0 0 0 0 0 0
AmmobacuHtes dilatatus 0 0 0 0 0 0
AmmobacuHtes exiguas 0 0 0 0 0 0
AmmobacuHtes subcatenulatus 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 0 0
Ammotium salsum 0 0 0 0 0 0
Arenoparrella mexicana 0 0 0 0 0 0
Elphidium excavatum 1 0 0 0 2 0
Elphidium galvestonense 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 0 0 0 0 0 0
Miliammina peiila 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Tiphotrocha comprimata 0 0 0 0 0 0
Trochammina inflata 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
‘CURO IS6G1 not included because it was barren of foraminifera.
204
Name ALB01S1C2 ALB01S2G1 ALB01S3C2 ALB01S4C2 ALB01S5C2 ALB01S6C2
No. of Living Specimens Picked 2 1 15 17 8 69
Fraction Picked 1/32 53/1440 13/720 1/144 2/45 11/256
Calc. Specimens per 50 cm’ 64 27 831 2448 180 1605
Ammoasiula inepta 0 0 0 0 0 0
AmmobacuHtes crassus 0 0 1 7 1 47
Ammobaculiles dilatalus 0 0 0 0 0 0
AmmobacuHtes exiguus 0 0 0 0 0 0
Ammobaculiles subcalenulatus 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 0 0
Ammolium salsum 0 1 12 10 5 22
Arenoparrella mexicana 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Haplophra^moides bonplandi 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 2 0 2 0 2 0
Miliammina petila 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Tiphotrocha comprimata 0 0 0 0 0 0
Trochammina inflata 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
205
Name ALB0IS8C2 ALL01SIC2 ALL0IS2C2 ALLOIS3C2 ALLO 1S4C2 ALL0IS5C2
No. of Living Specimens Picked 73 0 0 2 2 3
Fraction Picked 31/72 5/384 7/576 8/45 I/I 7/360
Calc. Specimens per 50 cm' 142 0 0 11 2 154
Ammoastula inepta 0 0 0 0 0 0
Ammobaculiies crassus 65 0 0 0 0 0
AmmobacuHtes dHatalus 1 0 0 0 0 0
Ammobaculiies exiguas 0 0 0 0 0 0
Ammobaculiies subcalenulaius 1 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 0 0
Ammolium sahum 6 0 0 0 0 0
Arenoparrella mexicana 0 0 0 0 0 0
E/phidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 0 0 0 2 2 3
Miliammina peiila 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Tipholrocha comprimala 0 0 0 0 0 0
Trochammina ínflala 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
206
Name PAS0IS1C2 PAS0IS2C2 PAS0IS3C2 NOROISIC2 NOROIS2C2 CUR0ISIC2
No. of Living Specimens Picked 4 16 1 3 23 20
Fraction Picked 127/2880 1/48 13/720 1/64 1/288 67/3840
Calc. Specimens per 50 cm' 91 768 55 192 6624 1146
Ammoastuta inepta 0 0 0 0 0 0
Ammobaculites crassus 1 0 1 1 1 1
AmmobacutUes dHatatus 0 0 0 0 0 0
Ammobaculites exiguas 0 0 0 0 0 0
Ammobaculites subcatenulatus 0 2 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 0 0
Ammotium salsum 2 2 0 2 22 19
Arenoparrella mexicana 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 0 12 0 0 0 0
Miliammina petila 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Tiphotrocha comprimata 1 0 0 0 0 0
Trochammina in/lata 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
207
Name CUR0IS2GI CUROIS4G1 CUR01S5C2 CUR01S7G1 CUR01S9GI CUROISIOGI
No. of Living Specimens Picked 6 46 12 8 1 15
Fraction Picked 151/1440 59/1440 1/64 1/256 13/5760 I/I
Calc. Specimens per 50 cm' 57 1123 768 2048 5760 15
Ammoasluta inepta 0 0 0 0 0 0
Ammobaculiles crassus 0 5 0 0 0 2
Ammobaculiles dilatalus 0 0 0 0 0 0
Ammobaculites exi^uus 0 0 0 0 0 0
Ammobaculiles subcatenulatus 0 16 0 1 0 4
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 0 0
Ammotium salsum 2 10 Í2 7 1 0
Arenoparrelia mexicana 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Jadammina macrescens 0 2 0 0 0 0
Miliammina fusca 4 13 0 0 0 9
Miliammina petila 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Tipholrocha comprimata 0 0 0 0 0 0
Trochammina Ínflala 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
208
Name CRC)0ISIC2 CROOIS2G1 CROOIS3C2 CRO01S4G1 CRO01S6G1 CRO01S7C2
Live Picked 22 5 12 17 0 16
Fraction Picked 3/128 1/18 5/128 79/2880 31/1152 41/5760
Calc. Specimens per 50 cm' 939 90 307 620 0 2248
Ammoastuta inepta 0 0 0 6 0 0
Ammobaculiles crassus 8 4 5 0 0 1
Ammobacutites dilatatus 0 0 0 0 0 0
Ammobaculiles exiguas 0 0 0 0 0 0
Ammobaculiles subcatenulatus 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 0 1
Ammotium salsum 14 1 7 0 0 1
Arenoparrella mexicana 0 0 0 1 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 2 0 0
Jadammina macrescens 0 0 0 2 0 0
Miliammina fusca 0 0 0 3 0 13
MUiammina petila 0 0 0 3 0 0
Reophax sp. 0 0 0 0 0 0
Tiphotrocha comprímala 0 0 0 0 0 0
Trochammina Ínflala 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
209
Name ROA01S1C2 R0A01S2G1 ROA01S4C2 ROA01S5G1 ROA01S7GI ROA01S9G1
No. of Living Specimens Picked 7 6 5 27 21 0
Fraction Picked 1/360 1/1 7/5760 1/144 1/10 1/1
Calc. Specimens per 50 cm’ 2520 6 4114 3888 210 0
Ammoastuta inepta 0 0 0 0 0 0
Ammobaculiles crassus 7 1 1 4 14 0
AmmobacuHtes dilatalus 0 1 0 0 0 0
Ammobaculiles exiguus 0 0 0 0 0 0
Ammobaculiles subcalenulalus 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 3 0 1 0 0
Ammotium sabum 0 1 0 2 5 0
Arenoparrella mexicana 0 0 0 4 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 0 0 4 13 2 0
Miliammina petila 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Tiphotrocha comprimata 0 0 0 1 0 0
Trochammina Ínflala 0 0 0 2 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
210
Name PAM01S2G1 PAM01S5G1 PAM01S6GI PAM0IS7GI PAM0IS8GI PAM01S9GI
No. of Living Specimens Picked 4 174 73 196 267 173
Fraction Picked 1/1 1/15 3/32 3/20 38/45 13/128
Calc. Specimens per 50 cm' 4 2610 779 1307 316 1703
Ammoastuta inepta 0 0 0 0 0 0
Ammobaculites crassus 3 13 29 1 14 7
Ammobaculiles dilatatus 0 1 0 0 0 1
Ammobaculites exiguas 0 2 2 3 1 3
Ammobaculites subcatenulatus 0 0 0 0 0 0
Ammonia parkinsoniana 0 50 0 0 0 0
Ammonia sp. {organic lining) 0 0 4 0 0 1
Ammotium salsum 1 84 38 145 209 159
Arenoparrella mexicana 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 2 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 0 22 0 47 26 2
Miliammina petila 0 0 0 0 0 0
Reophax sp. 0 0 0 0 4 0
Tiphotrocha comprímala 0 0 0 0 0 0
Trochammina inflata 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 13 0
Appendix B. Species proportions of live specimens expressed as relative abundance (%)
within each sample, numbers of species per sample (S), and biofacies grouping.
212
Name BEAOISIGI BEA01S2G1 BEA01S3G1 INSOISIGI EBBOISIGI OFFOISIGI
Number of Species (S) 1 0 0 0 1 0
Biofacies Grouping 2 2
Ammoastuta inepta 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHles crassus 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHtes dilalatus 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHles exiguas 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHtes subcalenulatus 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.00 0.00 0.00 0.00 0.00 0.00
ArenoparreHa mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 1.00 0.00 0.00 0.00 1.00 0.00
Elphidium gaivestonense 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
?CURO 1S6G1 not included because it was barren of foraminifera
213
Name ALB01S1C2 ALB01S2GI ALB01S3C2 ALB0IS4C2 ALB01S5C2 ALB01S6C2
Number of Species (S) 1 1 3 2 3 2
Biofacies Grouping 1 3 3 3 3 4
Ammoasluta inepta 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites crassus 0.00 0.00 0.07 0.41 0.13 0.68
Ammobaculiles dilalalus 0.00 0.00 0.00 0,00 0.00 0.00
Ammobaculites exiguas 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculiles subcatenulaius 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.00 1.00 0.80 0.59 0.63 0.32
Arenoparretla mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galveslonense 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 1.00 0.00 0.13 0.00 0.25 0.00
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimala 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina Ínflala 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
214
Name ALB01S8C2 ALL01S1C2 ALL01S2C2 ALL01S3C2 ALL01S4C2 ALL0IS5C2
Number of Species (S) 4 0 0 1 1 1
Biofacies Grouping 4 1 1 1
Ammoasiuta inepta 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuUtes crassus 0.89 0.00 0.00 0.00 0.00 0.00
Ammobaculites dilalalus 0.01 0.00 0.00 0.00 0.00 0.00
AmmobacuUtes exiguus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites subcatenulatus O.OI 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.08 0.00 0.00 0.00 0.00 0.00
Arenoparrella mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Hapiophragmoides bonpiandi 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.00 0.00 0.00 1.00 1.00 1.00
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
215
Name PAS01S1C2 PAS01S2C2 PAS01S3C2 NOROIS 1C2 NOR01S2C2 CUR01S1C2
Number of Species (S) 3 3 1 2 2 2
Biofacies Grouping 3 1 4 3 3 3
Ammoastuta inepta 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites crassus 0.25 0.00 1.00 0.33 0.04 0.05
Ammobaculites dilatatus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites exiguas 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites subcatenulatus 0.00 0.13 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.50 0.13 0.00 0.67 0.96 0.95
Arenoparrella mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.00 0.75 0.00 0.00 0.00 0.00
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.25 0.00 0.00 0.00 0.00 0.00
Trochammina in/lata 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
216
Name CUR01S2GI CUR01S4G1 CUR0IS5C2 CUR0IS7GI CUR01S9G1 CUROISIOGl
Number ofSpecies (S) 2 5 1 2 1 3
Biofacies Grouping 1 1 3 3 3 1
Ammoastuta inepta 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHtes crassus 0.00 0.11 0.00 0.00 0.00 0.13
AmmobacuHtes dilalalus 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHtes exiguas 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHtes subcatenulatus 0.00 0.35 0.00 0.13 0.00 0.27
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.33 0.22 1.00 0.88 1.00 0.00
Arenoparrella mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.04 0.00 0.00 0.00 0.00
Miliammina fusca 0.67 0.28 0.00 0.00 0.00 0.60
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina Ínflala 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
217
Name CRO01S1C2 CROOIS2G1 CRO01S3C2 CRO01S4G1 CRO01S6G1 CRO01S7C2
Number of Species (S) 2 2 2 6 0 4
Biofacies Grouping 3 4 3 1 1
Ammoasluta inepta 0.00 0.00 0.00 0.35 0.00 0.00
Ammobaculites crassus 0.36 0.80 0.42 0.00 0.00 0.06
Ammobaculites dilatatus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites exiguus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites subcatenulatus 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.06
Ammotium salsum 0.64 0.20 0.58 0.00 0.00 0.06
Arenoparrella mexicana 0.00 0.00 0.00 0.06 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.12 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.12 0.00 0.00
Miliammina fusca 0.00 0.00 0.00 0.18 0.00 0.81
Miliammina petila 0.00 0.00 0.00 0.18 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina in/lata 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
218
Name ROAOISIC2 ROAOIS2GI ROA01S4C2 ROA0IS5GI ROA0IS7GI ROAOIS9GI
Number of Species (S) 1 4 2 7 3 0
Biofacies Grouping 4 1 1 1 4
Ammoastuta inepta 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculiles crassus 1.00 0.17 0.20 0.15 0.67 0.00
Ammobaculiles dilatatus 0.00 0.17 0.00 0.00 0.00 0.00
Ammobaculites exi^uus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculiles subcatenulatus 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.50 0.00 0.04 0.00 0.00
Ammotium salsum 0.00 0.17 0.00 0.07 0.24 0.00
Arenoparrella mexicana 0.00 0.00 0.00 0.15 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.00 0.00 0.80 0.48 0.10 0.00
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comphmala 0.00 0.00 0.00 0.04 0 00 0.00
Trochammina inflata 0.00 0.00 0.00 0.07 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
219
Name PAM0IS2GI PAM0IS5GI PAM0IS6GI PAM0IS7GI PAM0IS8GI PAM0IS9GI
Number of Species (S) 2 7 4 4 5 6
Biofacies Grouping 4 3 3 3 3 3
Ammoastula inepta 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites crassus 0.75 0.07 0.40 0.01 0.05 0.04
AmmobaculUes dilalalus 0.00 0.01 0.00 0.00 0.00 0.01
Ammobaculites exiguus 0.00 0.01 0.03 0.02 0.00 0.02
Ammobaculites subcatenulatus 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.29 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.05 0.00 0.00 0.01
Ammotium salsum 0.25 0.48 0.52 0.74 0.78 0.92
Arenoparrella mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.01 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.00 0.13 0.00 0.24 0.10 0.01
Miliammina petHa 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.01 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.05 0.00
Appendix C. Numbers of dead specimens per sample, total number picked, fraction
picked, and calculated numbers of specimens per 50 cm^.
221
Name BEAOISIGI BEA01S2G1 BEA01S3G1 INSOISIGl EBBOISIGI OFFOISIGI
No. of Dead Specimens Picked 63 10 5 135 143 101
Fraction Picked |/| 1/1 I/I 1/2 1/1 1/1
Calc. Specimens per 50 cm 63 10 5 270 143 101
Ammoastuta inepta 0 0 0 0 0 0
Ammobaculites crassus 0 1 0 0 0 5
AmmobaculUes dilatatus 0 0 0 0 0 2
Ammobaculites exiguus 0 0 0 0 0 1
AmmobaculUes subcaienulalus 0 0 0 0 0 0
AmmobaculUes sp. 0 0 0 0 0 0
Ammonia parkinsoniana 1 0 0 1 3 5
Ammonia lepida 0 0 0 0 0 2
Ammonia sp. (organic lining) 0 0 0 0 0 0
Ammotium salsum 0 0 0 0 0 0
Arenoparrella mexicana 0 0 0 0 0 1
Buccella frigida 0 0 0 0 1 0
Elphidium excavatum 61 8 4 130 139 83
Elphidium galvestonense 0 0 0 1 0 0
Elphidium subarcticum 0 1 0 2 0 0
Elphidium sp. 0 0 0 1 0 0
Hanzawaia strattoni 1 0 1 0 0 1
Haplophragmoides bonplandi 0 0 0 0 0 0
Haplophragmoides hancocki 0 0 0 0 0 0
Haplophragmoides manilaensis 0 0 0 0 0 0
Haplophragmoides wilberti 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 0 0 0 0 0 0
Miliammina petila 0 0 0 0 0 0
Pseudothurammina limnetis 0 0 0 0 0 0
Reophax nana 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Siphotrochammina lobata 0 0 0 0 0 0
Tiphotrocha comprimata 0 0 0 0 0 1
Trochammina compacta 0 0 0 0 0 0
Trochammina in/lata 0 0 0 0 0 0
Trochammina lobata 0 0 0 0 0 0
Trochammina "squamata " 0 0 0 0 0 0
Trochamminita irregularis 0 0 0 0 0 0
Trochamminita salsa 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
Indeterminate organic lining 0 0 0 0 0 0
*CUROI S6G1 not included because it was barren of foraminifera.
Ill
Name ALB01SIC2 ALB01S2GI ALB01S3C2 ALB01S4C2 ALB0IS5C2 ALB0IS6C2
No. of Dead Specimens Picked 325 207 230 219 294 220
Fraction Picked 1/32 53/1440 13/720 1/144 2/45 11/256
Calc. Specimens per 50 cm’ 10400 5624 12295 31392 6615 5120
Ammoaslula inepta 0 1 1 1 0 0
AmmobacuHtes crassus 15 47 31 73 214 159
AmmobacuUtes dilatalus 0 0 0 5 0 0
AmmobacuHtes exiguas 0 0 0 0 0 0
AmmobacuHtes subcatenulatus 149 39 20 4 1 2
AmmobacuHtes sp. 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia tepida 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 1 0
Ammotium salsum 53 112 172 135 77 57
Arenoparrella mexicana 0 0 0 0 0 0
Buccella frigida 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium ^alvestonense 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0
Elphidium sp. 0 0 0 0 0 0
Hanzawaia strattoni 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Haplophragmoides hancocki 0 0 0 0 0 0
Haplophragmoides manilaensis 0 0 0 0 0 0
Haplophragmoides wilberti 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 108 8 6 1 1 0
Miliammina petila 0 0 0 0 0 0
Pseudothurammina Hmnetis 0 0 0 0 0 0
Reophax nana 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Siphotrochammina lobata 0 0 0 0 0 0
Tiphotrocha comprimata 0 0 0 0 0 0
Trochammina compacta 0 0 0 0 0 0
Trochammina inflata 0 0 0 0 0 0
Trochammina lobata 0 0 0 0 0 0
Trochammina "squamata " 0 0 0 0 0 0
Trochamminita irregularis 0 0 0 0 0 0
Trochamminita salsa 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 2
Indeterminate organic lining 0 0 0 0 0 0
223
Name ALB01S8C2 ALL01S1C2 ALL01S2C2 ALL01S3C2 ALL01S4C2 ALL01S5C2
No. of Dead Specimens Picked 220 200 275 312 49 294
Fraction Picked 31/72 5/384 7/576 8/45 1/1 7/360
Calc. Specimens per 50 cm’ 426 15360 22629 1755 47 15120
Ammoastuta inepta 1 22 4 4 1 9
Ammobaculites crassus 173 70 26 221 46 97
AmmobacuHtes dilalalus 12 0 1 0 0 3
Ammobaculites exiguas 1 0 0 0 0 0
Ammobaculites subcatenulatus 0 0 0 0 0 0
Ammobaculites sp. 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia tepida 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 1 0 0 0
Ammotium salsum 32 67 228 74 2 140
Arenoparrella mexicana 0 3 1 0 0 1
Buccella frigida 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0
Elphidium sp. 0 0 0 0 0 0
Hanzawaia strattoni 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 0 0 0
Haplophragmoides hancocki 0 0 0 0 0 0
Haplophragmoides manilaensis 0 1 0 0 0 1
Haplophragmoides wilberti 0 0 0 0 0 0
Jadammina macrescens 0 5 0 0 0 0
Miliammina fusca 0 18 14 13 2 43
Miliammina petila 0 1 0 0 0 0
Pseudothurammina Hmnetis 0 0 0 0 0 0
Reophax nana 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Siphotrochammina lobata 0 1 0 0 0 0
Tiphotrocha comprimata 0 0 0 0 0 0
Trochammina compacta 0 0 0 0 0 0
Trochammina inflata 0 0 0 0 0 0
Trochammina lobata 0 0 0 0 0 0
Trochammina "squamata " 0 0 0 0 0 0
Trochamminita irregularis 0 0 0 0 0 0
Trochamminita salsa 0 10 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
Indeterminate organic lining 1 2 0 0 0 0
224
Name PAS01S1C2 PAS01S2C2 PAS01S3C2 NOR01S1C2 NOR01S2C2 CUR0IS1C2
No. of Dead Specimens Picked 247 253 242 214 200 262
Fraction Picked 127/2880 1/48 13/720 1/64 1/288 67/3840
Calc. Specimens per 50 cm’ 5601 12144 13403 13696 57600 15074
Ammoaslula inepta 0 2 1 4 2 0
AmmobacuHtes crassus 33 18 45 70 50 18
AmmobacuHtes dilatatus 3 5 0 9 4 1
AmmobacuHtes exiguas 0 0 0 0 0 0
AmmobacuHtes subcatenulatus 53 115 63 18 15 27
AmmobacuHtes sp. 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia tepida 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 I 0 1 0
Ammotium salsum 144 90 114 100 120 215
Arenoparrella mexicana 0 0 0 0 0 0
Buccetla frígida 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Elphidium subarciicum 0 0 0 0 0 0
Elphidium sp. 0 0 0 0 0 0
Hanzawia strattoni 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 1 1 0
Haplophragmoides hancocki 0 0 0 0 0 0
Haplophragmoides manilaensis 0 0 0 0 0 0
Haplophraf^moides wilberti 0 0 0 0 0 0
Jadammina macrescens 0 0 0 0 0 0
Miliammina fusca 14 23 15 12 7 1
Miliammina petila 0 0 0 0 0 0
Pseudothurammina limnetis 0 0 0 0 0 0
Reophax nana 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Siphotrochammina lobata 0 0 0 0 0 0
Tiphotrocha comprimata 0 0 0 0 0 0
Trochammina compacta 0 0 0 0 0 0
Trochammina inflata 0 0 0 0 0 0
Trochammina lobata 0 0 0 0 0 0
Trochammina "squamata " 0 0 0 0 0 0
Trochamminila irregularis 0 0 0 0 0 0
Trochamminita salsa 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
Indeterminate organic lining 0 0 3 0 0 0
225
Name CUR0IS2GI CUROIS4G1 CUR0IS5C2 CUR0IS7G1 CUR01S9GI CUROISIOGI
No. of Dead Specimens Picked 282 206 254 259 299 104
Fraction Picked 151/1440 59/1440 1/64 1/256 13/5760 1/1
Calc. Specimens per 50 cm' 2689 5028 16256 66304 127163 104
Ammoastuta inepta 72 2 0 0 0 1
Ammobaculites crassus 3 4 82 38 36 17
Ammobaculites ditalalus 0 1 0 9 3 0
Ammobaculites exiguas 0 0 0 1 0 0
Ammobaculites subcatenulatus 1 37 19 7 12 59
Ammobaculites sp. 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia tepida 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 0 1
Ammotium salsum 0 42 152 203 246 17
Arenopanella mexicana 0 1 0 0 0 0
Buccella frigida 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0
Elphidium sp. 0 0 0 0 0 0
Hanzawaia strattoni 0 0 0 0 0 0
Haplophra^moides bonplandi 0 16 0 0 0 0
Haplophragmoides hancocki 0 3 0 0 0 0
Haplophragmoides manilaensis 3 12 0 0 0 0
Haplophragmoides wilberti 3 1 0 0 0 0
Jadammina macrescens 52 26 0 0 0 2
Miliammina fusca 20 12 1 1 1 7
Miliammina petila 100 16 0 0 0 0
Pseudothurammina limnetis 15 0 0 0 0 0
Reophax nana 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Siphotrochammina lobata 1 0 0 0 0 0
Tiphotrocha comprimata 2 19 0 0 0 0
Trochammina compacta 0 0 0 0 0 0
Trochammina in/lata 0 0 0 0 0 0
Trochammina lobata 0 0 0 0 0 0
Trochammina "squamata " 0 0 0 0 0 0
Trochamminita irregularis 4 12 0 0 0 0
Trochamminita salsa 6 2 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
Indeterminate organic lining 0 0 0 0 1 0
226
Name CRO01SIC2 CROOIS2G1 CRCX)1S3C2 CRO01S4G1 CRO01S6G1 CRC)01S7C2
No. of Dead Specimens Picked 238 307 221 239 240 253
Fraction Picked 3/128 1/18 5/128 79/2880 31/1152 41/5760
Calc. Specimens per 50 cm 10154 5526 5658 8749 8956 35683
Ammoaslula inepta 0 0 0 28 2 6
Ammobaculites crassus 151 227 163 28 168 78
Ammobaculites dilatatus 1 5 1 0 1 0
Ammobaculites exiguus 0 0 0 0 1 0
Ammobaculites subcatenulatus 1 0 0 1 3 0
Ammobaculites sp. 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia tepida 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 0 0 0 2 3
Ammotium salsum 83 75 55 20 59 113
Arenoparrella mexicana 0 0 0 22 0 5
Buccella frigida 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium ^alvestonense 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0
Elphidium sp. 0 0 0 0 0 0
Hanzawaia strattoni 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 0 25 1 1
Haplophragmoides hancocki 0 0 0 1 0 0
Haplophragmoides manilaensis 0 0 0 5 0 1
Haplophragmoides wilberti 1 0 1 9 0 9
Jadammina macrescens 0 0 0 6 2 3
Miliammina fusca 1 0 1 64 1 32
Miliammina petila 0 0 0 12 0 2
Pseudothurammina limnetis 0 0 0 6 0 0
Reophax nana 0 0 0 0 0 0
Reophax sp. 0 0 0 0 0 0
Siphotrochammina lobata 0 0 0 1 0 0
Tiphotrocha comprimata 0 0 0 8 0 0
Trochammina compacta 0 0 0 0 0 0
Trochammina in/lata 0 0 0 3 0 0
Trochammina lobata 0 0 0 0 0 0
Trochammina "squamata " 0 0 0 0 0 0
Trochamminita irregularis 0 0 0 0 0 0
Trochamminita salsa 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
Indeterminate organic lining 0 0 0 0 0 0
227
Name ROA01S1C2 ROA01S2G1 ROA01S4C2 ROA0IS5G1 ROA01S7G1 ROA01S9GI
No. of Dead Specimens Picked 290 87 320 238 254 3
Fraction Picked 1/360 1/1 7/5760 1/144 l/IO 1/1
Calc. Specimens per 50 cm’ 104400 87 261669 34272 2750 3
Ammoastuta inepta 0 0 1 1 5 0
AmmobacuiUes crassus 151 52 63 78 142 1
Ammobaculites dilatalus 5 0 43 8 0 1
AmmobacuUtes exiguas 1 4 1 1 2 0
Ammobaculites subcatenulatus 0 0 0 0 12 0
AmmobacuUtes sp. 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 0
Ammonia tepida 0 0 0 0 0 0
Ammonia sp. (organic lining) 0 2 0 1 0 0
Ammotium salsum 129 23 155 3 3 0
Arenoparrelia mexicana 0 0 3 13 1 0
Buccella frigida 0 0 0 0 0 0
Elphidium excavatum 0 0 0 0 0 0
Elphidium galvestonense 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0
Elphidium sp. 0 0 0 0 0 0
Hanzawaia strattoni 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 1 5 1 0
Haplophragmoides hancocki 0 0 0 10 0 0
Haplophragmoides manilaensis 0 0 1 0 20 0
Haplophragmoides wilberti 0 0 1 2 20 1
Jadammina macrescens 0 0 1 3 31 0
Miliammina fusca 4 5 41 94 2 0
Miliammina petila 0 0 1 2 7 0
Pseudothurammina limnetis 0 0 0 0 0 0
Reophax nana 0 0 3 2 0 0
Reophax sp 0 0 1 1 0 0
Siphotrochammina lobata 0 0 0 0 0 0
Tiphotrocha comphmata 0 1 3 6 7 0
Trochammina compacta 0 0 0 1 0 0
Trochammina inflata 0 0 1 7 1 0
Trochammina lobata 0 0 0 0 0 0
Trochammina "squamata " 0 0 0 0 0 0
Trochamminita irregularis 0 0 0 0 0 0
Trochamminiia salsa 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
Indeterminate organic lining 0 0 0 0 0 0
228
Name PAM0IS2GI PAM01S5G1 PAM0IS6GI PAM01S7G1 PAM0IS8GI PAM01S9GI
No. of Dead Specimens Picked 78 157 219 92 11 79
Fraction Picked 1/1 1/15 3/32 3/20 38/45 13/128
Calc. Specimens per 50 cm’ 78 2355 2336 613 13 876
Ammoaslula inepta 0 0 0 0 0 0
Ammobaculites crassus 27 18 61 2 4 15
Ammobaculiles dilatatus 0 2 0 4 0 1
Ammobaculites exiguas 5 0 0 0 0 3
Ammobaculites subcatenulatus 0 0 0 0 0 0
Ammobaculites sp. 0 0 0 0 0 1
Ammonia parkinsoniana 0 8 0 0 0 0
Ammonia iepida 0 0 0 0 0 0
Ammonia sp. (organic lining) 1 6 17 0 0 0
Ammotium salsum 35 61 112 63 0 38
Arenoparrella mexicana 0 4 0 0 0 0
Buccella frigida 0 0 0 0 0 0
Elphidium excavatum 1 1 0 0 0 0
Elphidium ^alvestonense 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0
Elphidium sp. 0 0 0 0 0 0
Hanzawaia strattoni 0 0 0 0 0 0
Haplophragmoides bonplandi 0 0 1 0 0 0
Haplophragmoides hancocki 0 1 0 0 0 0
Haplophragmoides manilaensis 0 0 1 0 0 0
Haplophragmoides wilberii 0 4 0 0 0 0
Jadammina macrescens 1 0 16 0 0 0
Miliammina fusca 7 20 0 23 4 19
Miliammina petila 0 0 0 0 0 0
Pseudothurammina limnetis 0 0 0 0 0 0
Reophax nana 0 0 0 0 0 0
Reophax sp. 0 4 0 0 3 0
Sipholrochammina lobata 0 0 1 0 0 1
Tiphotrocha comprimata 0 4 10 0 0 0
Trochammina compacta 0 1 0 0 0 0
Trochammina inflata 0 22 0 0 0 1
Trochammina lobata 0 1 0 0 0 0
Trochammina "squamata " 1 0 0 0 0 0
Trochamminita irregularis 0 0 0 0 0 0
Trochamminita salsa 0 0 0 0 0 0
Indeterminate aggl. unilocular sp. 0 0 0 0 0 0
Indeterminate organic lining 0 0 0 0 0 0
Appendix D. Species proportions of dead specimens expressed as relative abundance
(%) within each sample, numbers of species per sample (S), species diversity (H(S)),
equitability (E), and biofacies grouping.
230
Name BEAOISIGI BEA0IS2GI BEAOIS3GI INSOISIGI EBBOISIGI OFFOISIGI
Number of Species (S) 3 3 2 3 3 8
Species Diversity H(S) 0.16 0.64 0.50 0.21 0.14 0.80
Equitability (E) 0.39 0.63 0.82 0.41 0.38 0.28
Biofacies Grouping A A A A A A
Ammoastuta inepta 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculiles crassus 0.00 0.10 0.00 0.00 0.00 0.05
Ammobaculiles dilatalus 0.00 0.00 0.00 0.00 0.00 0.02
Ammobaculiles exiguas 0.00 0.00 0.00 0.00 0.00 0.01
Ammobaculiles subcatenulalus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculiles sp. 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.02 0.00 0.00 0.01 0.02 0.05
Ammonia lepida 0.00 0.00 0.00 0.00 0.00 0.02
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.00 0.00 0.00 0.00 0.00 0.00
Arenoparreila mexicana 0.00 0.00 0.00 0.00 0.00 0.01
Buccella frígida 0.00 0.00 0.00 0.00 0.01 0.00
Elphidium excavatum 0.97 0.80 0.80 0.96 0.97 0.82
Elphidium gaivestonense 0.00 0.00 0.00 0.01 0.00 0.00
Elphidium subarcticum 0.00 0.10 0.00 0.01 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.01 0.00 0.00
Hanzawia siraltoni 0.02 0.00 0.20 0.00 0.00 0.01
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides hancocki 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides manilaensis 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides wilberli 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Pseudothurammina limnelis 0.00 0.00 0.00 0.00 0.00 0.00
Reophax nana 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Sipholrochammina lobala 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.01
Trochammina compacta 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina "squamata " 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita irregularis 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita salsa 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate organic lining 0.00 0.00 0.00 0.00 0.00 0.00
?CUR01S6G1 not included because it was barren of foraminifera.
231
Name ALBOISIC2I ALB01S2GI 1 ALB0IS3C2 ALB01S4C2 ALB01S5C2 ALB01S6C2
Number of Species (S) 4 5 5 6 5 3
Species Diversity H(S) 1.16 1.13 0.82 0.87 0.64 0.67
Equitability (E) 0.80 0.62 0.45 0.40 0.38 0.65
Biofacies Grouping D c c c B B
Ammoastuia inepta 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHíes crassus 0.05 0.23 0.13 0.33 0.73 0.72
AmmobacuHles dilalatus 0.00 0.00 0.00 0.02 0.00 0.00
Ammobaculites exiguus 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHles subcatenulalus 0.46 0.19 0.09 0.02 0.00 0.01
Ammobaculites sp. 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia tepida 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.16 0.54 0.75 0.62 0.26 0.26
Arenoparrella mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Buccella frígida 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium subarcticum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.00 0.00 0.00
Hanzawia siraltoni 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides hancocki 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides manilaensis 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides wilberti 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.33 0.04 0.03 0.00 0.00 0.00
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Pseudothurammina limnetis 0.00 0.00 0.00 0.00 0.00 0.00
Reophax nana 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Siphotrochammina lobato 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina compacta 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina lobato 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina "squamata " 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita irregularis 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita salsa 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.01
Indeterminate organic lining 0.00 0.00 0.00 0.00 0.00 0.00
232
Name ALB01S8C2 ALL01S1C2 ALL01S2C2 ALL0IS3C2 ALL01S4C2 ALL0IS5C2
Number of Species (S) 5 10 7 4 4 7
Species Diversity H(S) 0.70 1.62 0.65 0.77 0.27 1.19
Equitability (E) 0.40 0.51 0.27 0.54 0.33 0.47
Biofacies Grouping B c C B B c
Ammoastuta inepta 0.00 0.11 0.01 0.01 0.02 0.03
Ammobaculiles crassus 0.79 0.35 0.09 0.71 0.94 0.33
Ammobaculites dilata tus 0.05 0.00 0.00 0.00 0.00 0.01
Ammobaculiles exiguus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculiles subcalenulalus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculiles sp. 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia tepida 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.00
Ammotium salsum 0.15 0.34 0.83 0.24 0.04 0.48
Arenoparella mexicana 0.00 0.02 0.00 0.00 0.00 0.00
Buccella frígida 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavalum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium subarcticum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.00 0.00 0.00
Hanzawia siraloni 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides hancocki 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides manilaensis 0.00 0.01 0.00 0.00 0.00 0.00
Haplophragmoides wilberti 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.03 0.00 0.00 0.00 0.00
Miliammina fusca 0.00 0.09 0.05 0.04 0.00 0.15
Miliammina pelila 0.00 0.01 0.00 0.00 0.00 0.00
Pseudoihurammina limnelis 0.00 0.00 0.00 0.00 0.00 0.00
Reophax nana 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Sipholrochammina lobala 0.00 0.01 0.00 0.00 0.00 0.00
Tiphoirocha comprímala 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina campada 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina Ínflala 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina "squamata ” 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminila irregularis 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita salsa 0.00 0.05 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate organic lining 0.00 0.01 0.00 0.00 0.00 0.00
233
Name PAS01S1C2 PAS0IS2C2 PAS0IS3C2 NOR01S1C2 NOROIS2C2 CUR0IS1C2
Number of Species (S) 5 6 6 7 8 5
Species Diversity H(S) 1.13 1.25 1.29 1.32 1.14 0.62
Equitability (E) 0.62 0.58 0.61 0.54 0.39 0.37
Biofacies Grouping C D c c c c
Ammoastuta inepta 0.00 0.01 0.00 0.02 0.01 0.00
Ammobaculites crassus 0.13 0.07 0.19 0.33 0.25 0.07
Ammobaculites dilatalus 0.01 0.02 0.00 0.04 0.02 0.00
Ammobaculites exiguas 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites subcatenulatus 0,21 0.45 0.26 0.08 0.08 0.10
Ammobuculites sp. 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia tepida 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.01 0.00
Ammotium salsum 0.58 0.36 0.47 0.47 0.60 0.82
Arenoparella mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Buccella frígida 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium subarcticum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.00 0.00 0.00
Hanzawia stratoni 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.01 0.00
Haplophragmoides hancocki 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides manilaensis 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides wiiberti 0.00 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.00 0.00 0.00 0.00 0.00 0.00
Miliammina fusca 0.06 0.09 0.06 0.06 0.04 0.00
MUiammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Pseudothurammina limnelis 0.00 0.00 0.00 0.00 0.00 0.00
Reophax nana 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Siphotrochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina compacta 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina "squamata " 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita irregularis 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita salsa 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate organic lining 0.00 0.00 0.01 0.00 0.00 0.00
234
Name CUR01S2GI CUR01S4G1 CUR01S5C2 CUR01S7G1 CUR01S9G11 CUROISIOGI
Number of Species (S) 12 15 4 6 5 7
Species Diversity H(S) 1.73 2.31 0.89 0.73 0.61 1.26
Equitability (E) 0.47 0.67 0.61 0.35 0.37 0.50
Biofacies Grouping E E C c c D
Ammoastuta inepta 0.26 0.01 0.00 0.00 0.00 0.01
Ammobaculites crassus 0.01 0.02 0.32 0.15 0.12 0.16
AmmobacuHtes dHalatus 0.00 0.00 0.00 0.03 0.01 0.00
Ammobaculites exiguas 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites subcatenulatus 0.00 0.18 0.07 0.03 0.04 0.57
Ammobaculites sp. 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia iepida 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.00 0.01
Ammotium salsum 0.00 0.20 0.60 0.78 0.82 0.16
Arenoparrella mexicana 0.00 0.00 0.00 0.00 0.00 0.00
Buccella frígida 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium subarcticum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.00 0.00 0.00
Hanzawia strattoni 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.08 0.00 0.00 0.00 0.00
Haplophragmoides hancocki 0.00 0.01 0.00 0.00 0.00 0.00
Haplophragmoides manilaensis 0.01 0.06 0.00 0.00 0.00 0.00
Haplophragmoides wilberti 0.01 0.00 0.00 0.00 0.00 0.00
Jadammina macrescens 0.18 0.13 0.00 0.00 0.00 0.02
Miliammina fusca 0.07 0.06 0.00 0.00 0.00 0.07
Miliammina petila 0.35 0.08 0.00 0.00 0.00 0.00
Pseudothurammina limnetis 0.05 0.00 0.00 0.00 0.00 0.00
Reophax nana 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Siphotrochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprímala 0.01 0.09 0.00 0.00 0.00 0.00
Trochammina compacta 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina Ínflala 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina "squamata " 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita irregularis 0.01 0.06 0.00 0.00 0.00 0.00
Trochamminita salsa 0.02 0.01 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate organic lining 0.00 0.00 0.00 0.00 0.00 0.00
235
Name CRO01SIC2 CRO01S2GI CRO0IS3C2 CROOIS4GI CRO01S6G1 CRO01S7C2
Number of Species (S) 6 3 5 14 10 11
Species Diversity H(S) 0.75 0.63 0.64 2.30 0.86 1 46
Equitability (E) 0.35 0.63 0.38 0.71 0.24 0.39
Biofacies Grouping B B B E B c
Ammoastula inepta 0.00 0.00 0.00 0.12 0.01 0.02
Ammobaculites crassus 0.63 0.74 0.74 0.12 0.70 0.31
Ammobaculites dilatalus 0.00 0.02 0.00 0.00 0.00 0.00
Ammobaculites exiguus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites subcatenulatus 0.00 0.00 0.00 0.00 0.01 0.00
Ammobaculites sp. 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia tepida 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.00 0.00 0.00 0.01 0.01
Ammotium salsum 0.35 0.24 0.25 0.08 0.25 0.45
Arenoparrella mexicana 0.00 0.00 0.00 0.09 0.00 0.02
Buccella frigida 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium subarcticum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.00 0.00 0.00
Hanzawia strattoni 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.10 0.00 0.00
Haplophragmoides hancocki 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides manilaensis 0.00 0.00 0.00 0,02 0.00 0.00.
Haplophragmoides wilberti 0.00 0.00 0.00 0.04 0.00 0.04
Jadammina macrescens 0.00 0.00 0.00 0.03 0.01 0.01
Miliammina fusca 0.00 0.00 0.00 0.27 0.00 0.13
Miliammina petila 0.00 0.00 0,00 0.05 0.00 0.01
Pseudothurammina limnetis 0.00 0.00 0.00 0.03 0.00 0.00
Reophax nana 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Siphotrochammina lobato 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.00 0.00 0,03 0.00 0.00
Trochammina compacta 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.01 0.00 0.00
Trochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina "squamata " 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita irregularis 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita salsa 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate organic lining 0.00 0.00 0.00 0.00 0.00 0.00
236
Name ROAOISIC2 ROAOIS2GI ROA01S4C2 ROA0IS5G1 ROAOIS7G1 ROA01S9G1
Number of Species (S) 5 6 15 16 14 3
Species Diversity H(S) 0.85 1.10 1.50 1.76 1.60 1.10
Equitability (E) OAl 0.50 0.30 0.36 0.35 1.00
Biofacies Grouping B c c E B B
Ammoastuta inepta 0.00 0.00 0.00 0.00 0.02 0.00
AmmobacuUtes crassus 0.52 0.60 0.20 0.33 0.56 0.33
Ammobaculites dilatatus 0.02 0.00 0.13 0.03 0.00 0.33
AmmobacuUtes exiguas 0.00 0.05 0.00 0.00 0.01 0.00
Ammobaculites subcatenulatus 0.00 0.00 0.00 0.00 0.05 0.00
AmmobacuUtes sp. 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia parkinsoniana 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia tepida 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.00 0.02 0.00 0.00 0.00 0.00
Ammotium salsum 0.44 0.26 0.48 0.01 0.01 0.00
Arenoparrella mexicana 0.00 0.00 0.01 0.05 0.00 0.00
BucceUa frígida 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium galvesionense 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium subarcticum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.00 0.00 0.00
Hanzawia strattoni 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.02 0.00 0.00
Haplophragmoides hancocki 0.00 0.00 0.00 0.04 0.00 0.00
Haplophragmoides manilaensis 0.00 0.00 0.00 0.00 0.08 0.00
Haplophragmoides wilberti 0.00 0.00 0.00 0.01 0.08 0.33
Jadammina macrescens 0.00 0.00 0.00 0.01 0.12 0.00
Miliammina fusca 0.01 0.06 0.13 0.39 0.01 0.00
Miliammina petila 0.00 0.00 0.00 0.01 0.03 0.00
Pseudothurammina limnetis 0.00 0.00 0.00 0.00 0.00 0.00
Reophax nana 0.00 0.00 0.01 0.01 0.00 0.00
Reophax sp. 0.00 0.00 0.00 0.00 0.00 0.00
Siphotrochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Tiphotrocha comprimata 0.00 0.01 0.01 0.03 0.03 0.00
Trochammina compacta 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina inflata 0.00 0.00 0.00 0.03 0.00 0.00
Trochammina lobata 0.00 0.00 0.00 0.00 0.00 0.00
Trochammina "squamata ” 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita irregularis 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita salsa 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate organic lining 0.00 0.00 0.00 0.00 0.00 0.00
237
Name PAM0IS2G1 PAM01S5GI PAM01S6GI PAM0IS7G1 PAM01S8GI PAM01S9G1
Number of Species (S) 7 13 9 4 3 7
Species Diversity H(S) 1.34 1.99 1.30 0.83 1.09 1.36
Equitability (E) 0.55 0.56 0.41 0.57 0.99 0.55
Biofacies Grouping c C C C C E
Ammoastuta inepta 0.00 0.00 0.00 0.00 0.00 0.00
AmmobacuHtes crassus 0.35 0.11 0.28 0.02 0.36 0.19
Ammobaculites dilata tus 0.00 0.01 0.00 0.04 0.00 0.01
AmmobacuHtes exi^uus 0.06 0.00 0.00 0.00 0.00 0.04
Ammobaculites subcalenulatus 0.00 0.00 0.00 0.00 0.00 0.00
Ammobaculites sp. 0.00 0.00 0.00 0.00 0.00 0.01
Ammonia parkinsoniana 0.00 0.05 0.00 0.00 0.00 0.00
Ammonia tepida 0.00 0.00 0.00 0.00 0.00 0.00
Ammonia sp. (organic lining) 0.01 0.04 0.08 0.00 0.00 0.00
Ammotium salsum 0.45 0.39 0.51 0.68 0.00 0.48
Arenoparrella mexicana 0.00 0.03 0.00 0.00 0.00 0.00
Buccella frigida 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium excavatum 0.01 0.01 0.00 0.00 0.00 0.00
Elphidium galvestonense 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium subarcticum 0.00 0.00 0.00 0.00 0.00 0.00
Elphidium sp. 0.00 0.00 0.00 0.00 0.00 0.00
Hanzawia strattoni 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides bonplandi 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides hancocki 0.00 0.01 0.00 0.00 0.00 0.00
Haplophragmoides manilaensis 0.00 0.00 0.00 0.00 0.00 0.00
Haplophragmoides wilberti 0.00 0.03 0.00 0.00 0.00 0.00
Jadammina macrescens 0.01 0.00 0.07 0.00 0.00 0.00
Miliammina fusca 0.09 0.13 0.00 0.25 0.36 0.24
Miliammina petila 0.00 0.00 0.00 0.00 0.00 0.00
Pseudothurammina limnetis 0.00 0.00 0.00 0.00 0.00 0.00
Reophax nana 0.00 0.00 0.00 0.00 0.00 0.00
Reophax sp. 0.00 0.03 0.00 0.00 0.27 0.00
Siphotrochammina lobata 0.00 0.00 0.00 0.00 0.00 0.01
Tiphotrocha comprimata 0.00 0.03 0.05 0.00 0.00 0.00
Trochammina compacta 0.00 0.01 0.00 0.00 0.00 0.00
Trochammina injlata 0.00 0.14 0.00 0.00 0.00 0.01
Trochammina lobata 0.00 0.01 0.00 0.00 0.00 0.00
Trochammina "squamata " 0.01 0.00 0.00 0.00 0.00 0.00
Trochamminita irregularis 0.00 0.00 0.00 0.00 0.00 0.00
Trochamminita salsa 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate aggl. unilocular sp. 0.00 0.00 0.00 0.00 0.00 0.00
Indeterminate organic lining 0.00 0.00 0.00 0.00 0.00 0.00
Appendix E. Radionuclide tracer data and grain-size data (% < 63 (4.m) (from Letrick,
2003) for each of the 27 cores analyzed.
Albemarle Sound
ALBOISI
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALBOISICI 1.0 13.1 1,5 8.8 1.5 1.5 0.1 4.3 0.2 95.6
ALBOISICl 3.0 9.8 1.3 5.5 1.3 1.5 0.1 4.2 0.1 97.4
ALBOISICI 5.5 9.5 2.0 5.7 2.0 1.8 0.1 3.8 0.3 94.9
ALBOISICI 8.5 8.7 1.9 4.8 1.9 2.4 0.1 3.9 0.4 93.1
ALBOISICI 1 1.5 8.7 1.2 4.8 1.2 2.7 0.1 3.9 0.2 91.8
ALBOISICI 14.5 7.9 1.2 3.8 1.2 3.8 0.1 4.1 1.2 94.1
ALBOISICI 17.5 7.7 LI 3.9 1.2 5.2 0.1 3.8 0.3 94.8
ALBOISICI 20.5 5.6 0.9 2.5 1.0 5.5 0.1 3.6 0.3 95.1
ALBOISICI 23.5 5.7 0.9 1.9 0.9 0.8 0.1 3.8 0.1 96.4
ALBOISICI 26.5 4.6 1.3 1.2 1.3 0.2 0.1 3.5 0.2 97.1
ALBOISICI 29.5 4.1 1.0 0.9 1.0 0.0 0.1 3.2 0.2 97.0
ALBOISICI 32.5 3.9 1.0 0.7 1.0 0.0 0.1 3.2 0.2 96.5
ALBOISICI 35.5 95.1
ALBOISICI 38.5 4.7 2.3 0.9 2.3 0.0 0.0 3.8 0.1 96.4
ALB01S2
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALB01S2C1 1.0 13.3 1.5 11.2 1.5 1.1 0.1 2.2 0.2 84.5
ALB01S2C1 3.0 10.8 1.2 8.9 1.2 LI 0.1 1.9 0.1 89.1
ALB01S2C1 5.5 7.4 1.0 5.3 1.0 0.9 0.1 2.2 0.1 89.2
ALB01S2C1 8.5 2.7 0.8 0.9 0.9 0.4 0.1 1.8 0.1 62.1
ALB01S2C1 11.5 0.4 1.0 0.0 1.5 0.0 0.0 2.0 0.2 59.4
ALB01S2C1 14.5 1.8 0.7 0.2 0.7 0.1 0.0 1.5 0.2 76.9
ALB0IS2C1 17.5 0.0 0.0 0.0 0.0 0.0 0.0 1.8 0.0 74.0
ALB01S2C1 20.5 LI 0.6 -0.4 0.6 0.0 0.0 1.5 0.1 59.0
ALB01S2C1 23.5 74.4
ALB01S2C1 26.5 2.3 0.9 0.7 0.9 0.0 0.0 1.6 0.2 75.0
ALB01S2C1 29.5 82.2
ALB01S2C1 32.5 0.7 0.7 -1.1 0.7 0.1 0.0 1.9 0.1 81.5
240
Albemarle Sound
ALB01S3
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALB01S3CI 1.0 13.1 1.5 11.4 1.5 1.2 0.1 1.7 0.1 80.8
ALB01S3C1 3.0 12.4 1.4 10.7 1.4 1.1 0.1 1.7 0.1 93.9
ALB01S3CI 5.5 5.1 1.3 3.7 1.3 0.6 0.1 1.4 0.2 85.4
ALB0IS3C1 8.5 3.6 0.9 2.2 0.9 0.1 0.0 1.4 0.2 65.4
ALB0IS3C1 11.5 1.9 0.5 0.3 0.5 0.0 0.0 1.7 0.1 82.6
ALB0IS3CI 14.5 0.0 0.0 0.0 0.1 0.0 0.0 1.5 0.1 74.8
ALB0IS3C1 17.5 0.9 0.4 0.0 0.5 0.0 0.0 1.4 0.2 71.2
ALB01S3CI 20.5 0.5 0.6 0.0 0.7 0.0 0.0 1.4 0.1 73.5
ALB01S3C1 23.5 0.4 0.6 0.0 0.6 0.0 0.0 1.3 0.1 76.6
ALB0IS3CI 26.5 0.2 0.6 0.0 0.6 0.0 0.0 1.2 0.2 66.9
ALB0IS3CI 29.5 1.4 0.6 0.1 0.6 0.0 0.0 1.3 0.1 75.3
ALB01S3C1 32.5 0.2 0.6 -1.0 0.6 0.0 0.0 1.2 0.2 68.1
ALB0IS3CI 35.5 62.0
ALB0IS3C1 38.5 1.4 0.6 0.1 0.6 0.0 0.0 1.3 0.1 57.3
ALB01S4
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALB01S4C1 1.0 9.6 1.1 8.1 1.1 1.0 0.1 1.5 0.1 68.4
ALB01S4C1 3.0 6.7 0.8 5.3 0.8 0.8 0.0 1.4 0.1 87.9
ALB01S4C1 5.5 2.8 0.8 1.5 0.8 0.5 0.1 1.3 0.1 57.5
ALB01S4C1 8.5 1.8 0.7 0.6 0.7 0.2 0.0 1.2 0.1 42.9
ALB01S4C1 11.5 0.8 1.1 0.0 0.7 0.0 0.1 1.5 0.1 53.1
ALB01S4C1 14.5 0.0 0.0 -1.2 0.0 0.0 0.0 1.2 0.0 42.2
ALB01S4C1 17.5 0.6 l.l 0.0 1.1 0.0 0.0 l.l 0.0 28.7
ALB01S4C1 20.5 0.7 0.6 -0.3 0.6 0.1 0.0 0.9 0.1 19.5
ALB0IS4C1 23.5 0.6 1.0 0.0 0.0 0.0 0.0 1.1 0.2 37.3
ALB01S4C1 26.5 1.2 0.5 0.3 0.6 0.0 0.0 1.0 0.1 22.6
ALB01S5
interval
midpoint XS Grain-size
•
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALB01S5C1 1.0 1.4 0.6 0.6 0.7 0.2 0.0 0.9 0.1 15.3
ALB01S5C1 3.0 2.0 0.7 1.1 0.7 0.1 0.0 0.8 0.1 12.4
ALB0IS5C1 5.5 0.5 0.6 0.0 0.6 0.1 0.0 0.7 0.1 8.5
ALB0IS5CI 8.5 0.0 0.0 0.0 0.1 0.1 0.0 0.6 0.1 11.2
ALB0IS5CI 11.5 0.9 0.2 0.3 0.2 0.0 0.0 0.6 0.1 13.8
Albemarle Sound
ALB01S6
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALB01S6C1 1.0 1.6 0.4 l.l 0.4 0.0 0.0 0.5 0.1 2.5
ALB01S6CI 3.0 0.3 0.6 -0.2 0.6 0.1 0.0 0.5 0.0 2.2
ALB01S6CI 5.5 0.4 0.4 -0.2 0.4 0.1 0.0 0.6 0.1 2.6
ALB01S6CI 8.5 1.5 0.6 1.0 0.6 0.0 0.0 0.5 0.0 2.8
ALB01S6C1 11.5 0.4 0.5 -0.1 0.5 0.1 0.0 0.5 0.1 2.7
ALBO 1S6C1 14.0 0.0 0.5 -0.5 0.5 0.1 0.0 0.5 0.1 1.9
ALB01S8
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALB01S8CI 1.0 0.0 0.0 0.1 0.0 0.4 0.1 1.0
ALB01S8C1 3.0 0.0 0.0 0.0 0.3 0.1 1.2
ALB01S8C1 5.5 0.0 0.0 0.0 0.3 0.1 l.l
ALB01S8C1 8.5 0.0 0.0 0.0 0.3 0.0 0.8
ALB01S8CI 11.5 0.0 0.0 0.0 0.3 0.1 1.1
ALB01S8CI 14.5 0.0 0.0 0.0 0.3 0.1 0.9
Alligator River
ALLOISI
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALLOISICI 1.0 6.9 0.7 6.0 0.7 0.6 0.1 0.9 0.1 63.7
ALLOISICI 3.0 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 67.5
ALLOISICI 5.5 0.4 0.8 0.0 0.0 0.0 0.0 1.0 0.1 70.6
ALLOISICI 8.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 64.1
ALLOISICI 11.5 1.3 0.3 0.0 0.0 0.0 0.0 1.0 0.1 69.7
ALLOISICI 14.5 0.5 0.8 0.0 0.0 0.0 0.0 0.9 0.2 70.9
ALLOISICI 17.5 0.6 0.4 0.0 0.0 0.0 0.0 0.9 0.2 69.9
ALLOISICI 20.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 71.4
Alligator River
ALL01S2
Interval
midpoint xs Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALL0IS2C1 1.0 7.6 0.8 6.6 0.8 0.7 0.1 1.0 0.1 60.0
ALL01S2CI 3.0 8.7 0.8 7.4 0.8 0.8 0.1 1.3 0.1 52.3
ALL0IS2C1 5.5 3.3 0.7 2.4 0.7 0.6 0.1 0.9 0.1 47.5
ALL0IS2C1 8.5 2.5 0.7 1.4 0.7 0.9 0.1 II 0.1 36.4
ALL0IS2C1 11.5 2.8 II 2.0 II 1.6 0.1 0.8 0.0 38.6
ALL01S2CI 14.5 1.6 0.6 0.5 0.6 1.5 0.1 II 0.1 51.1
ALL01S2CI 17.5 1.6 0.7 0.5 0.7 0.5 0.0 1.2 0.1 43.6
ALL01S2CI 20.5 0.6 0.5 0.0 0.0 0.1 0.0 0.9 0.2 81.4
ALLO 1 S3
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALL01S3CI 1.0 0.0 0.0 0.0 0.0 0.0 0.0 1.4 0.2 77.1
ALL01S3C1 3.0 0.0 0.0 0.0 0.0 0.0 0.0 1.4 0.1 85.7
ALL0IS3C1 5.5 1.0 0.7 0.0 0.0 0.0 0.0 1.3 0.4 87.7
ALL01S3C1 8.5 0.4 0.6 0.0 0.0 0.0 0.0 1.3 0.2 88.3
ALL01S3CI 11.5 0.9 0.5 0.0 0.0 0.0 0.0 1.6 0.1 87.9
ALL01S5
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ALL01S5C1 1.0 5.0 0.5 3.9 0.6 0.4 0.1 1.1 0.2 27.1
ALL01S5C1 3.0 1.6 0.3 0.6 0.5 0.2 0.0 1.0 0.3 26.7
ALL01S5C1 5.5 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.2 18.4
ALL01S5C1 8.5 0.0 0.0 0.0 0.0 0.1 0.0 0.7 0.1 15.2
ALL01S5C1 11.5 0.5 0.4 0.0 0.0 0.0 0.0 0.8 0.1 33.5
ALL01S5C1 14.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 28.8
ALL01S5C1 17.5 0.7 0.4 0.0 0.0 0.0 0.0 1.0 0.1 60.5
ALL01S5C1 20.5 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.1 54.5
ALL01S5C1 23.5 57.8
ALL01S5C1 26.5 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.1 53.8
ALL01S5C1 29.0 0.1 0.5 0.0 0.0 0.0 0.1 1.1 0.1 61.2
243
East Lake
EL02S1
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
EL02S1C1 1.0 13.8 1.8 12.7 1,8 II 0.1 1.0 0.2 75.7
EL02S1C1 3.0 12.5 1.6 11.5 1.6 1.4 0.1 1.0 0.1 83.3
EL02SIC1 5.0 9.9 1.3 9.0 1.4 II 0.1 1.0 0.2 87.3
EL02SIC1 7.0 6.5 0.9 5.6 0.9 0.8 0.0 0.9 0.1 48.5
EL02SIC1 9.0 1.8 0.7 1.0 0.7 0.3 0.0 0.8 0.1 82.6
EL02SIC1 11.0 2.8 0.6 1.7 0.6 0.3 0.0 1.1 0.1 88,1
EL02SIC1 13.0 1.9 0.4 1.0 0.5 0.2 0.0 0.9 0.1 55.7
EL02SIC1 15.0 0.1 0.5 0.0 0.0 0.0 0.0 0.9 0.1 53.1
EL02SICI 17.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.1 69.3
EL02SICI 19.0 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.2 80.7
EL02S1CI 21.0
EL02S1CI 23.0
EL02SIC2 25.0
EL02S1C3 27.0 1.3 0.6 0.5 0.6 0.0 0.0 0.8 0.1
South Lake
SL02S1
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
SL02S1C1 1.0 28.0 3.4 26.7 3.4 2.7 0.1 1.3 0.1 87.5
SL02S1C1 3.0 23.9 2.9 22.8 2.9 3.2 0.1 l.l 0.1 88.6
SL02S1C1 5.0 19.9 2.4 18.6 2.4 3.8 0.0 1.2 0.1 85.5
SL02SICI 7.0 18.2 2.2 16.9 2.2 4.1 0.1 1.3 0.1 83.4
SL02SICI 9.0 19.1 2.4 17.7 2.4 4.5 0.1 1.4 0.0 84.1
SL02SrCI 11.0 15.0 1.9 13.7 1.9 5.1 0.1 1.3 0.2 84.8
SL02SIC1 13.0 8.8 1.2 7.3 1.2 4.1 0.1 1.5 0.2 89.5
SL02S1C1 15.0 5.2 0.8 3.8 0.8 1.6 0.1 1.4 0.1 89.4
SL02S1C1 17.0 4.2 0.6 2.8 0.6 1.1 0.0 1.4 0.1 82.5
SL02S1CI 19.0 3.5 0.6 2.2 0.6 0.9 0.1 1.3 0.1 82.9
SL02S1CI 21.0 2.6 0.5 1.3 0.5 0.4 0.1 1.3 0.2 83.9
SL02SIC1 23.0 83.2
SL02SIC1 25.0 1.5 0.5 0.3 0.5 0.2 0.1 1.3 0.1 82.6
SL02SIC1 27.0 86.6
SL02S1C1 29.0 1.8 0.5 0.4 0.5 0.1 0,0 1.4 0.1 81.5
244
Pasquotank River
PASOISI
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
PASOISICI 1.0 16.5 1.8 14.7 1.8 3.1 0.1 1.8 0.1 82.7
PASOISICI 3.0 10.2 1.2 9.1 1.2 1.4 0.1 l.l 0.1 85.7
PASOISICI 5.5 5.5 0.8 4.3 0.8 0.9 0.1 1.2 0.0 77.6
PASOISICI 8.5 4.1 0.7 3.0 0.7 0.4 0.1 l.l 0.1 78.4
PASOISICI 11.5 3.7 0.6 2.4 0.6 0.3 0.0 1.3 0.1 80.4
PASOISICI 14.5 3.2 0.6 1.8 0.6 0.1 0.0 1.4 0.2 78.8
PASOISICI 17.5 2.0 0.5 0.5 0.5 0.1 0.0 1.5 0.2 79.8
PASOISICI 20.5 2.8 0.6 1.3 0.6 0.0 0.0 1.5 0.1 82.5
PASOISICI 23.5 84.0
PASOISICI 26.5 1.7 0.4 0.4 0.4 0.1 0.0 1.3 0.1 84.6
PAS01S2
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
PAS0IS2CI 1.0 12.8 1.4 11.4 1.4 1.6 0.1 1.5 0.1 85.0
PAS0IS2CI 3.0 11.4 1.4 10.2 1.4 1.9 0.1 1.2 0.1 83.2
PAS0IS2CI 5.5 7.8 0.9 6.5 0.9 3.0 0.1 1.3 0.1 87.0
PAS0IS2CI 8.5 3.6 1.0 2.3 0.9 1.4 0.1 1.3 0.1 91.3
PAS0IS2CI 11.5 2.6 0.9 1.2 0.8 0.7 0.1 1.4 0.0 91.4
PAS0IS2CI 14.5 2.3 1.2 0.7 1.0 0.1 0.1 1.5 1.0 80.0
PAS0IS2CI 17.5 2.0 0.8 0.6 0.7 0.2 0.1 1.4 0.2 75.7
PAS0IS2CI 20.5 1.9 0.5 0.3 0.5 0.0 0.0 1.7 0.1 76.7
PAS0IS2CI 23.5 89.4
PAS0IS2CI 26.5 2.5 1.0 0.9 0.9 0.1 0.1 1.6 0.2 77.7
PAS0IS2CI 29.5 86.8
PAS0IS2CI 32.5 1.2 0.8 0.0 0.0 0.0 0.0 1.8 0.1 90.5
245
Pasquotank River
PAS01S3
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Eiror Ra-226 Error (% < 63 mm)
PAS01S3C1 1.0 5.7 0.8 4.1 0.8 1.3 0.1 1.6 0.2 97.6
PAS0IS3C1 3.0 4.9 0.7 2.8 0.7 1.2 0.1 2.1 0.2 95.3
PAS0IS3CI 5.5 3.8 1.0 2.2 0.9 0.4 0.1 1.6 0.2 96.8
PAS0IS3C1 8.5 2.6 0.5 0.9 0.5 0.0 0.0 1.7 0.1 96.8
PAS0IS3CI 11.5 1.2 0.7 0.0 0.7 0.1 0.1 1.5 0.2 96.1
PAS01S3C1 14.5 2.0 0.5 0.4 0.5 0.0 0.0 1.7 0.0 94.9
PAS0IS3C1 17.5 1.8 0.4 0.1 0.4 0.0 0.0 1.7 0.1 89.2
PAS01S3C1 20.5 1.7 0.4 0.2 0.4 0.0 0.0 1.5 0.0 88.9
PAS01S3C1 23.5 1.9 0 4 0.3 0.4 0.0 0.0 1.6 0.0 89.5
PAS0IS3C1 26.5 l.l 0.4 0.0 0.4 0.0 0.0 1.6 0.1 94.6
PAS01S3C1 29.5 0.0 0.0 0.0 0.3 0.2 0.1 1.4 0.3 97.5
PAS0IS3CI 32.5 0.2 0.9 0.0 0.9 0 1 0.1 1.6 0.1 97.9
PAS01S3CI 35.5 0.5 0.7 0.0 0.7 0.0 0.0 1.5 0.1 94.3
PAS0IS3CI 38.5 2.0 0.5 0.2 0.5 0.0 0.0 1.8 0.1 92.4
PAS0IS3CI 41.5 2.6 0.5 0.7 0.5 0.0 0.0 1.9 0.1 77.2
PAS01S3C1 44.5 0.6 0.7 0.0 0.7 0.0 0.1 1.8 0.1 60.5
PAS01S3CI 47.5 0.6 0.0 0.0 0.3 0.0 0.1 1.7 0.3 63.6
PAS01S3CI 50.5 1.3 0.7 0.0 0.7 0.1 0.1 1.8 0.2 53.9
PAS01S3C1 53.5 1.5 0.7 0.0 0.8 0.0 0.1 1.6 0.1 71.2
PAS01S3CI 56.5 1.4 0.9 0.0 1.0 0.0 0.0 1.6 0.4 90.1
PAS0IS3CI 59.5 2.3 0.5 0.6 0.5 0.0 0.0 1.7 0.1 86.8
North River
NOROISI
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
NOROISICI 1.0 8.6 1.0 7.3 1.0 0.8 0.1 1.3 0.1 61.3
NOROISICI 3.0 6.8 0.8 5.6 0.8 0.7 0.0 1.2 0.1 46.3
NOROISICI 5.5 3.8 0.5 2.5 0.5 0.5 0.0 1.2 0.1 43.6
NOROISICI 8.5 2.1 0.9 0.9 0.8 0.4 0.1 1.2 0.3 65.3
NOROISICI 11.5 2.2 0.7 0.9 0.6 0.1 0.0 1.3 0.1 84.4
NOROISICI 14.5 2.1 0.4 0.3 0.4 0.0 0.0 1.7 0.1 94.4
NOROISICI 17.5 2.5 0.9 0.9 0.8 0.0 0.0 1.7 0.2 49.0
NOROISICI 20.5 0.4 0.8 0.0 0.8 0.0 0.1 1.7 0.1 94.1
NOROISICI 23.5 2.2 0.6 0.5 0.5 0.0 0.0 1.7 0.2 94.0
NOROISICI 26.5 1.8 1.0 0.1 0.9 0.0 0.0 1.7 1.9 94.4
NOROISICI 29.5 94.1
NOROISICI 32.5 2.1 0.5 0.1 0.6 0.0 0.0 2.0 0.1 96.5
246
North River
NOR01S2
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
NOROIS2C1 1.0 6.1 0.7 5.0 0.7 0.5 0.0 1.1 0.1 58.0
NOROIS2C1 3.0 4.0 0.6 2.9 0.6 0.4 0.0 1.1 0.1 45.4
NOR01S2C1 5.5 2.2 0.4 1.3 0.4 0.2 0.0 0.9 0.0 32.5
NOROIS2C1 8.5 1.6 0.6 0.7 0.6 0.3 0.0 1.0 0.1 38.8
NOR01S2C1 11.5 37.9
NOROIS2C1 14.5 1.9 0.6 0.7 0.9 0.1 0.0 1.1 0.1 50.4
NOR01S2C1 17.5 52.6
NOR01S2C1 20.5 0.9 0.3 0.0 0.0 0.0 0.0 1.0 0.1 42.4
NOROIS2C1 23.5 44.1
NOROIS2C1 26.5 0.5 0.1 0.3 0.1 0.0 0.0 0.2 0.1 51.1
Currituck Sound
CUROISI
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
CUROISICI 1.0 1.0 0.3 0.3 0.3 0.1 0.0 0.7 0.1 6.9
CUROISICI 3.0 1.2 0.3 0.5 0.3 0.1 0.0 0.7 0.1 7.0
CUROISICI 5.5 1.3 0.3 0.6 0.3 0.1 0.0 0.7 0.0 8.5
CUROISICI 8.5 0.8 0.4 0.1 0.4 0.1 0.0 0.7 0.1 8.3
CUROISICI 11.5 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.1 20.6
CUROISICI 14.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 21.5
CUROISICI 17.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 25.7
CUROISICI 20.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.0 21.0
CUROISICI 29.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 19.7
CUR01S3
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
CUR01S3C1 1.0 3.7 0.5 2.5 0.5 0.4 0.1 1.2 0.1 54.4
CUR01S3C1 3.0 1.9 0.4 1.0 0.4 0.3 0.1 1.0 0.1 47.2
CUR01S3C1 5.5 0.1 0.8 0.0 0.0 0.3 0.0 1.0 0.1 43.3
CUR01S3C1 8.5 0.0 0.0 0.0 0.0 0.3 0.1 0.9 0.0 29.9
CUR01S3C1 11.5 1.3 0.3 0.6 0.3 0.2 0.0 0.7 0.1 13.5
CUR01S3C1 14.5 0.0 0.0 0.0 0.0 0.1 0.0 0.7 0.2 8.9
CUR01S3C1 17.5 1.0 0.3 0.2 0.3 0.1 0.0 0.8 0.1 15.4
CUR01S3C1 20.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 54.8
CUR01S3C1 23.5 53.8
CUR01S3C1 26.5 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.1 73.5
247
Currituck Sound
CUR01S5
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
CUR0IS5CI 1.0 1.9 0.3 0.8 0.3 0.1 0.0 l.l 0.0 12.0
CUR0IS5CI 3.0 1.5 0.3 0.3 0.4 0.1 0.0 1.2 0.1 37.2
CUR0IS5C1 5.5 0.0 0.0 0.0 0.0 0.1 0.0 1.2 0.2 38.5
CUR01S5C1 8.5 l.l 0.8 0.0 0.0 0.0 0.0 1.2 0.1 31.3
CUR0IS5C1 11.5 2.6 0.7 1.4 0.8 0.0 0.0 1.2 0.1 34.4
CUR01S5C1 14.5 l.l 0.8 0.0 0.0 0.0 0.0 1.2 0.1 29.6
CURO 1 SSCI 17.5 0.0 0.0 0.0 0.0 0.0 0.0 1.2 0.2 54.3
CUR0IS5C1 20.5 1.0 0.8 0.0 0.0 0.0 0.0 l.l 0.1 31.0
CUR01S5C1 23.5 0.0 0.0 0.0 0.0 0.0 0.0 l.l 0.1 35 4
CUR01S8
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
CUR0IS8CI 1.0 2.9 1.1 1.5 l.l 0.4 0.1 1.5 0.1 42.4
CUR0IS8C1 3.0 1.7 1.0 0.4 1.0 0.2 0.1 1.3 0.1 30.0
CUR0IS8CI 5.5 1.7 0.9 0.4 0.9 0.4 0.0 1.3 0.2 49.7
CUR0IS8C1 8.5 2.4 0.6 1.0 0.6 0.5 0.0 1.4 0.1 51.6
CUR01S8CI 11.5 2.0 0.7 0.5 0.7 0.5 0.0 1.6 0.1 34.3
CUR01S8C1 14.5 0.8 0.9 0.0 0.0 0.8 0.1 1.5 0.1 37.9
CUR01S8CI 17.5 45.3
CUR0IS8CI 20.5 2.1 0.8 0.4 0.8 0.7 0.1 1.7 0.1 36.2
CUR0IS8CI 23.5 3.6 0.5 2.0 0.6 0.8 0.0 1.5 0.1 31.5
CUR0IS8CI 26.5 0.1 0.8 0.0 0.0 0.5 0.0 1.5 0.1 25.4
CUR01S8C1 29.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 23.5
Croatan Sound
CRO01S3
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
CROOIS3CI 1.0 1.5 0.4 0.9 0.4 0.1 0.0 0.6 0.1 18.5
CROOIS3C1 3.0 1.3 0.3 0.8 0.3 0.0 0.0 0.5 0.1 10.8
CRO01S3C1 5.5 1.2 0.4 0.4 0.4 0.0 0.0 0.8 0.0 69.0
CROOIS3CI 8.5 0.1 0.4 0.0 0.0 0.0 0.0 0.6 0.1 78.9
CROOIS3CI 11.5 0.9 0.4 0.0 0.4 0.0 0.0 0.9 0.0 80.7
CROOIS3CI 14.0 1.1 0.0 0.2 0.5 0.0 0.0 0.9 0.5 63.8
CRO01S6
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
CROOIS6C1 1.0 3.0 0.8 1.8 0.8 0.1 0.0 1.2 0.0 24.6
CRC)01S6CI 3.0 0.0 0.0 0.0 0.0 0.1 0.0 0.9 0.1 22.3
CRC)01S6CI 5.5 1.8 0.6 0.8 0.7 0.1 0.0 1.1 0.1 22.3
CRO01S6CI 8.5 4.4 l.l 3.2 1.0 0.2 0.1 1.2 0.2 30.5
CRO01S6CI 11.5 6.7 0.9 5.4 0.9 0.3 0.0 1.2 0.1 19.9
CRO01S6C1 14.5 4.5 1.0 3.4 1.0 0.3 0.0 l.l 0.1 25.9
CRO01S6C1 17.5 1.8 0.7 0.7 0.8 0.2 0.0 l.l 0.1 28.7
CRO01S6C1 20.5a 0.0 0.0 0.0 0.0 0.1 0.0 l.l 0.1 29.1
CRO01S6C1 23.0 1.3 0.7 0.3 0.7 0.2 0.0 1.0 0.0 15.7
249
Roanoke Sound
ROAOISI
Interval
midpoint xs Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ROAOISICI 1.0 3.1 0.4 2.1 0.5 0.3 0.1 1.0 0.1 30.3
ROAOISICI 3.0 0.4 0.7 0.0 0.0 0.2 0.0 0.9 0.1 22.4
ROAOISICI 5.5 1.0 0.6 0.0 0.6 0.2 0.0 1.0 0.1 15.3
ROAOISICI 8.5 l.l 0.6 0.3 0.6 0.2 0.0 0.8 0.1 16.8
ROAOISICI 11.5 1.6 0.6 0.6 0.6 0.3 0.0 1.0 0.1 20.9
ROAOISICI 14.5 0.7 0.5 0.0 0.0 0.1 0.0 0.9 0.1 25.3
ROAOISICI 17.5 0.4 0.7 0.0 0.0 0.1 0.0 l.l 0.1 20.8
ROAOISICI 20.5 0.0 0.0 0.0 0.0 0.1 0.0 1.0 0.0 30.8
ROAOISICI 23.5 21.9
ROAOISICI 26.5 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.1 21.8
ROA01S4
Interval
midpoint XS Grain-size
Core (cm) Pb-210 Error Pb-210 Error Cs-137 Error Ra-226 Error (% < 63 mm)
ROAOIS4CI 1.0 2.9 0.5 1.6 0.5 0.1 0.0 1.2 0.1 39.9
ROAOIS4CI 3.0 3.4 0.6 2.1 0.6 0.2 0.0 1.3 0.1 51.7
ROAOIS4CI 5.5 5.1 0.8 4.0 0.8 0.5 0.0 II 0.1 72.7
ROA0IS4CI 8.5 4.4 0.7 3.4 0.7 0.7 0.1 1.0 0.1 72.9
ROA0IS4CI 11.5 3.9 0.6 2.8 0.7 0.6 0.1 l.l 0.2 69.5
ROAOIS4CI 14.5 2.9 0.5 1.9 0.6 0.3 0.0 l.l 0.1 71.5
ROAOIS4CI 17.5 2.4 0.5 1.3 0.6 0.1 0.0 l.l 0.2 74.7
ROAOIS4CI 20.5 3.7 0.6 2.6 0.6 0.2 0.1 l.l 0.1 70.9
ROAOIS4CI 23.5 1.9 0.5 1.3 0.0 0.1 0.1 1.3 0.0 63.2
ROAOIS4CI 26.5 2.1 0.5 0.8 0.5 0.1 0.1 1.3 0.2 43.5
ROAOIS4CI 29.5 1.5 0.5 0.2 0.5 0.1 0.0 1.3 0.0 71.7
ROAOIS4CI 32.5 1.6 0.4 0.3 0.4 0.2 0.0 1.3 0.1 55.8
ROA01S4CI 35.5 2.3 0.6 1.0 0.6 0.1 0.0 1,2 0.1 51.7