New Radiocarbon Dates Confirm Late Pleistocene Human Occupation in the Pampas of Argentina at ca. 12,170 14C yrs BP: Evidence from Extinct Horse at the Arroyo Seco 2 Site

GUTIERREZ, M. A.; POLITIS, G. G.; RAFUSE, D. J.; STAFFORD, T.

San Francisco, California

Congreso; 80TH ANNUAL MEETING de la Society for American Archaeology; 2015

The Arroyo Seco 2 site (AS2) is a multi-component open air hunter-gatherer site located in the Pampean Region of Argentina. A recently published monograph summarized the current interpretations of the site, which contains bone remains of 11 extinct Pleistocene mammals, including Eutatus seguini, Glossotherium robustum, Megatherium americanum, Paleolama cf. wedelli, Toxodon platensis, Equus (Amerhippus) sp., Glyptodon sp., Hemiauchenia sp., Hippidion sp., Macrauchenia sp., and Mylodontinae. While there is a concentration of selected anatomical parts of Pleistocene species and a spatial and stratigraphic association between them and lithic artifacts, the evidence of anthropic processing marks on the Pleistocene fauna bone surface remained scarce. Taphonomic analysis identified a proximal ulna bone fragment of Equus (Amerhippus) sp. with conclusive processing marks (two impact points with their respective negative flake scars on opposite sides of the shaft as well as notches produced by impact failures). A new AMS 14C analysis of this specimen yielded a date of 12,170 + 45 14C yrs BP; which is consistent with a previously-obtained determination on Megatherium remains averaged to 12,172 + 42 14C yrs BP (4 averaged dates). This date confirms the validity of the late Pleistocene human occupation chronology at the Pampas of Argentina.