Clocking the arrival of Homo sapiens in the Southern Cone of South America

Abstract

The Southern Cone of South America (Argentina, Chile, Uruguay and SoutheasternBrazil) was the last continental mass colonized by humans. Until recently, thediscussion about the peopling of the Americas revolved around the Clovis First-Pre-Clovis debate. Nowadays, the axis of this debate has changed (it has beenconsistently proved that there were people in the Americas before Clovis) and thecentral debate is if humans were South of the Laurentide/Cordilleran Ice Sheetafter or before the onset of deglaciation (ca. 18 to 19 ky) of the Last Glacial Maximum(LGM). However, while several models have been proposed to uphold thefirst hypothesis, the second one is only supported by isolated site reports andsparse data. With very few exceptions, no coherent models have been proposedto integrate the few suggested pre-LGM sites sprawled in the continent. In thisscenario, a fine-grain study of the timing of the arrival and the spatial occupationsequences of the expansion process is significant to understand the pattern ofcolonization of Homo sapiens in the Americas. In this chapter, we summarize anddiscuss the evidence from some key sites in the Southern Cone with pre- andpost- onset of LGM deglaciation ages. We present a compilation of the earliest14C dates as a proxy of human presence in the Southern Cone, both from samples(charcoal, faunal remains, etc.) associated with human presence as well fromhuman skeletons. Based this data, we analyze the main chronological trends andspatial sequences in the region. Finally, we contrast our results from the SouthernCone with the new continental scale models of peopling of the Americas, basedon ancient DNA.