MICROMORPHOLOGY IN ARCHAEOLOGY: AN ANALYSIS OF EOLIAN AND ALLUVIAL SITE FORMATION PROCESSES IN THE MIDDLE RÍO NEGRO VALLEY, NORTHERN PATAGONIA, ARGENTINA

Abstract

Based on the results of a previous geoarchaeological study that reconstructed the landscape history of the Middle Río Negro Valley in Northern Patagonia, Argentina, this thesis analyzes previously collected sediments to confirm their depositional context (i.e., eolian or alluvial processes, as well as their depositional forms: alluvial floodplain deposits, eolian loess mantle, or eolian dune), and assess the impacts of eolian and alluvial site formation processes on the preservation of the archaeological record. To determine if the samples are consistent with their previously proposed depositional context a micromorphological analysis was conducted to identify the main characteristics (e.g., mineralogy, texture, shape/rounding, sorting, presence of organic matter, etc.) observed in thin section. The results of this analysis have concluded that the samples are consistent with their previously proposed depositional context. Due to the highly dynamic processes present in the Middle Río Negro Valley, the preservation potential of Late Pleistocene to Middle Holocene archaeological sites is moderate and sites are likely to be located on the older alluvial terraces, either deeply buried by eolian dunes or in the alluvial floodplain deposits. The preservation potential of Late Holocene archaeological sites in the Middle Río Negro Valley is excellent and deposits are likely to be found in the eolian loess mantle and alluvial floodplain deposits. Large parts of the Río Negro Negro Valley have yet to be systematically surveyed, providing a unique opportunity to further study these environments and to locate previously unidentified archaeological sites.