The human colonization of the Southeast Plains of South America: Climatic conditions, technological innovations and the peopling of Uruguay and south of Brazil

摘要

During the late Pleistocene and early Holocene, climatic, faunistic, and ecological changes could produce social readjustments and technological innovations in human populations that were exploring and colonizing the low southeastern plains of South America. In this paper, paleoecological and archaeological data are integrated to systematize and discuss different aspects of early human settlement in Uruguay and the south of Brazil. It is possible to recognize evidence of initial human dispersion by the region between similar to 14,000 and 13,100 cal BP (12,000 to 11,320 C-14 BP) during the late Pleistocene, when dry and cold climatic conditions prevailed in the region. Later, between 12,800 and 10,065 cal BP, a low plains Paleoamerican stemmed bifacial tradition emerged with three different techno-complexes, represented by Fishtail, Tigre, and Pay Paso projectile points. These groups were adapted to the grassland plains and characterized by the presence of wide-stemmed projectile points. The Fishtail point had been supplanted by the Tigre point, showing diversification in design of projectile points during the Pleistocene-Holocene transition. Approximately 12,000 to 11,200 cal BP in the middle Uruguay River, a social and technological reorganization occurred, along with the emergence of the Tigre techno-complex during post-Fishtail times. The advent of Tigre groups coincided with warmer and wetter climatic conditions, indicating the beginning of the Holocene. By 11,080-10,928 cal BP, new weaponry changes occurred in the region, including the production of the Pay Paso points, a regionally distinctive projectile-point style for the early Holocene. These aspects allow start discussions of cultural transmission, technological innovations and morphological variation in projectile point styles over the time and space. The field research developed over the past 15 years, in conjunction with the previous research conducted in southern Brazil, the relative high density of early sites with radiocarbon ages (n = 22), and the chronological base (67 radiocarbon ages), allow to formulate an archaeological and behavioral model about the initial peopling of the Uruguayan and southern Brazil plains. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.