Les premières occupations humaines dans le Sud du Brésil : une vision géoarchéologique intégrée

Between ≈13,000 and 7000 BP, the territory of southern Brazil was occupied in a stable and diverse manner, with the main anthropic trace being in lithic material. Archaeological research has provided more consistent evidence of occupation in different environments and associated with different stratigraphic formation processes since the Late Pleistocene. Therefore, this paper proposes to analyse the history of the earliest evidence of pre-colonial occupation in southern Brazil from a geoarchaeological point of view, focusing on stratigraphic and chronological data and the process of formation of archaeological layers. Thirty-three stratigraphic sections were analysed from 31 archaeological sites distributed along the Paraná, Uruguay and Atlantic basins. Evidence of archaeological levels was found in different geomorphological contexts: plateau, slopes, valley bottom, alluvial plains and rockshelters. The results indicate that the oldest archaeological levels in the region were formed in the Late Pleistocene, associated with periods of fluvial incision that signal important changes in the southern river systems, characterized by the formation of alluvial and colluvial-alluvial terraces in the valley bottoms. This is followed in the Lower Holocene by widespread colluvial processes in the incised valleys, alluvium in the middle river courses and anthropogenic deposits in the rockshelters that formed the main ancient levels. In the early Middle Holocene, sedimentary deposits containing archaeological material decrease significantly, marking regional changes in lithic industries. The data indicate that there appears to be a threshold between deposition and archaeology in the Early Holocene, characterized by high stratigraphic resolution, where stratigraphic sequences show greater thickness and density of archaeological levels. Finally, the diversity of inter-regional lithic assemblages is clearly highlighted, marked by the predominance of industries on pebbles and blocks, the debitage of flakes and blades as a support for various tools in the interior basins and the shaping of small projectile points on the Atlantic slope.