Geochronology, sediment provenance, and fossil emplacement at Sumidouro Cave, a classic Late Pleistocene/Early Holocene paleoanthropological site in eastern Brazil

Peter Wilhelm Lund's (1845a) heavily debated suggestion of a contemporaneity between Paleo-Indians and extinct Pleistocene fauna at Sumidouro Cave was re-examined through detailed sedimentological and geochronological analyses of sediment and both human and faunal remains. Sources of the cave's sediment include both entrances as well as ceiling fissures. Non-human fossils, on the other hand, were probably carried by floodwater through the once more-spacious swallet entrance. Seasonal flooding reworked and mixed these two highly asynchronous assemblages. U-series and radiocarbon ages indicate that there are at least two distinct episodes of sediment input in the cave, at -240,000 yr B.P. and -8000 yr B.P. Human remains represent a later emplacement event, probably at -8400 cal yr B.P. Although the human remains are of considerable age, the cave's complex stratigraphy, flooding dynamics, and extensive removal of the cave's filling during earlier excavations do not allow the determination of an unequivocal co-existence between Paleo-Indians and extinct megafauna at the site.