Palaeoenvironmental conditions during the early peopling of Southernmost South America (Late Glacial-Early Holocene, 14-8 ka B.P.)

Abstract

Environmental conditions in Southernmost South America (the Patagonian Andes and the extra-Andean plains) during the early peopling of the region in Late Glacial/Early Holocene times are herein described. Different glacial advances or stabilization phases in valley glaciers occurred several millennia after the Last Glacial Maximum (LGM), as a consequence of regional cold climatic episodes. According to Clapperton (1993), two advances during the Late Glacial took place, ca. 15-14 14 C ka and 12-10 14 C ka B.P. A cold event during this last period, probably correlative with the “Younger Dryas” episode in the Northern Hemisphere, has been observed in the palynological record. A tundra environment dominated until ca. 13-10 14 C ka B.P.; afterwards, a gramineous steppe with forest refuges developed. The transition steppe-forest lasted to the Middle Holocene, when the Nothofagus forest took over. The arrival of man in Southernmost South America (ca. 13 14 C ka B.P. or even before) probably took place while glaciers were still present in most Andean valleys, sea level was much lower than today, and tundra environments dominated the extra-Andean plains. Moreover, peopling in the Isla Grande de Tierra del Fuego would have occurred not later than 11.8 14 C ka B.P., when the present Magellan Straits valley was still occupied by a meltwater discharge, braided stream, fed by the receding “Magellan Glacier”.