The geoarchaeology of megamammal survival in the Pampas

POLITIS, GUSTAVO G.; CRISTIAN FAVIER DUBOIS; PABLO G. MESSINEO

Washington

Congreso; 83rd Annual Meeting of SAA; 2018

Society for American Archaeology

While most of the South American archaeological sites with extinct megamammals have produced Late Pleistocene ages (12,000 to 10,000 14C years BP), a few locations in the Pampas region have been dated well into the Early Holocene. Among these, Campo Laborde and La Moderna, two kill/scavenging and processing sites in the border of ancient swamps have provided 11 taxon dates (Megatherium americanum and Doedicurus clavicaudatus) which range between 9730 and 6550 14C years BP. Recent excavations in the Campo Laborde site, as well as detailed geoarchaeological studies and newly obtained amino acid radiocarbon dates, challenge the hypothesis of the Pleistocene megamammals? late survival in this region. In this presentation we will discuss new data considering the site formation processes of creek floodplains in the Pampas, in which the Holocene deposits are biased and the pedogenesis was intense. The studies in both locations suggest that the percolation of organic matter form upper layers would contaminate and rejuvenate the dates obtained from bone collagen.