Between Shell Layers. Processes Involved in the Formation of Don Enrique Archaeological Site (Punta Indio, Buenos Aires Province, Argentina)

Don Enrique archaeological site is located in the northern coastal plain of Samborombón Bay (Punta Indio, Buenos Aires province, Argentina). The aim of this investigation is to interpret the stratigraphic context of the site and the geomorphological processes involved in its origin and formation, through the integration of geomorphological, micropaleontological, and archeological analyses. Two exposed sedimentary profiles from the quarries ‘Cantera 1’ and ‘Cantera 2’ were analyzed. Numerous ceramic fragments, along with other archaeological materials were collected from the surface and within the sedimentary profiles. The characteristics of these remains revealed that the site is associated with hunter-gatherer groups. We interpret the unit with archaeological materials in ‘Cantera 1’ as a paleosoil, constituted over a beach ridge and buried by bioclastic deposits of a high-energy beach environment. In ‘Cantera 2’, the soil continued being formed by current climatic conditions, while in ‘Cantera 1’ it started a new pedogenesis process over the shell deposit. We propose that the observed differences between both sectors are related to the paleoshoreline position and its topographic configuration. Also, micropaleontological analysis suggests changing environmental conditions from an estuarine environment with higher marine influence to the establishment of more restricted estuarine conditions as a result of coastal progradation processes. Don Enrique represents the first surveyed archaeological site in the northern sector of Samborombón Bay, where archaeological materials were found in situ, specifically in a buried paleosoil. Two radiocarbon dates obtained from Mactra isabelleana indicate that the site was formed during the Late Holocene, ~1300–1200 cal years BP.