The potential use of the Argentine Continental Shelf during the human colonization of southern South America. Paleogeographic models and archaeological expectations

The analysis of human colonization of the southern tip of South America involves exploring diverse environmental and ecological changes, in addition to the important geographic transformations due to the retreat of ice fields and marine transgression during the late Pleistocene. In this paper, we examine the process of human colonization in southern Patagonia (south of parallel 47 degrees) between 15,000 and 10,000 cal yr BP by means of the following procedure. First, we performed a detailed bathymetric analysis and generated a series of palaeogeographic models using a Geographic Information System (GIS) and Digital Elevation Models (DEM). Secondly, based on the palaeogeographic reconstructions and available archaeological evidence, we examined hypothetical dispersal pathways in the region using GIS-generated Least Cost Path Analysis simulation models with special emphasis on sea level changes and physical spatial conditions. The results suggest that the Argentine Continental Shelf (ACS) may have played an important role in the early dispersal of hunter-gatherers in southern Patagonia, either by presenting lower impediments or costs for human mobility, possible ecological niches without analogues in other sectors of Patagonia, and favorable environmental conditions for human habitation. This expectation is also integrated within an existing framework of discussion about a geographically discontinuous distribution of human occupations recorded in the plateau sector of the region during the Pleistocene-Holocene transition, which possibly interacted with denser population nodes in the continental shelf sector.