Paleofires and vegetation in a Late Pleistocene paleolake (>43 ka bp) of the savannas of central Brazil

Abstract

This study investigates paleoenvironmental changes at the Paleolagoa Seca site, an Upper Quaternary locality of lacustrine origin in central Brazil. We present charcoal and pollen analyses of this sedimentary sequence, and assess how they compare with previously published fossil macroflora and paleoclimatic reconstructions of the same site and adjacent localities. We identified a mosaic of savannas, forests and flooded environments before 43 ka bp with the presence of evergreen forest formations. For this period, we found charcoal particles resulting from natural fires that represent the oldest Quaternary record of fire in the Cerrado. By conducting a morphological analysis of charcoal particles, we were able to identify that the primary constituents of fire fuel were grasses, which suggests that surface fires were prevalent. During this Pleistocene wet phase, fire probably played a vital role in preserving areas of open vegetation. In contrast, at ~43 ka bp, an open landscape and a drier-than-present climate characterized the Paleolagoa Seca site.