Biostratigraphy of the Pleistocene Fossiliferous Deposits of the Southern Brazilian Coastal Area

Abstract

Fossils of Pleistocene mammals have been discovered in the southern Brazilian coastal area since the late XIX century, in two main places: the continental shelf and the Chui Creek. Although the taxonomic composition of fossil assemblages from these areas has been the focus of most studies during the late XX century, research concerning the ages, stratigraphic position, and biostratigraphy of such assemblages remains scarce. This is due to the lack of suitable materials for age determination and the reworked nature of the fossiliferous deposits in the continental shelf. Only in recent years have new data shed light on these subjects. Taxonomic revisions, ESR ages, and biostratigraphic correlations confirm a late Pleistocene age for the fossil assemblages, although those from the shelf represent a significant time averaging, while fossils from the Chui Creek exhibit a narrower age range. The fossil mammals found in southern Brazil represent a mixture of Brazilian and Pampean taxa, including forms that disappeared much earlier from the Argentinean pampas. Gaining an understanding of the biostratigraphic context of such assemblages in comparison to similar assemblages from Argentina and Uruguay, in conjunction with stratigraphic, geomorphological, and paleoclimatic data should provide additional tools with which to reconstruct the environmental and climatic dynamics of this portion of South America during the late Pleistocene—early Holocene and its effects on the fauna, and possibly to help address the problem of the disappearance of megamammals in the area.