Another sequence, same evidence: human presence at the end of the Pleistocene in America. The Toca da Janela da Barra do Antonião, Piauí, Brazil

The site of Toca da Janela da Barra do Antonião (TJBA) is situated in the calcareous massif of Antero, in the Serra da Capivara National Park, Piauí State, Brazil. The entire rockshelter is more than 150m long, with few meters deep recesses. Part of the site was extensively studied in the 1990s [1]. Our team begun a wide archaeological program in the region in 2008 [2,3], focusing on different archaeological sequences. New archaeological excavations started in TJBA in 2013, at an extremity of the Toca, without possible stratigraphic correlation with previous excavations. After 3 archaeological campaigns, the bedrock was not reached. At the time of writing this abstract (April 2016), the site presents a 1.5 m thick chrono-cultural sequence, inside of which six sedimentary layers and four archaeological levels were identified. All the four archaeological layers delivered lithic and faunal remains. The two archaeological layers at the top of the sequence are separated by a thin sterile sediment layer, but present a cultural homogeneity, and both can be attributed to the Itaparica facies of the region. The two underlying archaeological levels are poorer in lithic artefacts; the lithics can be divided in three categories: small artefacts on quartz, big artefacts on quartz, and hammers. These two lower levels also delivered skeletal remains of a giant sloth corresponding to Eremotherium (megafauna); in particular, it seems that certain bones were used to produce artefacts. Charcoal samples from the upper part of the sequence were radiocarbon dated. In addition, six sediment samples were collected from the profile for luminescence dating. Sand-sized (180-250 μm) and fine (20-41μm) quartz grains were extracted from the samples and prepared following a standard chemical treatment. For all six samples, the quartz OSL signal is bright, reproducible and dominated by the fast component, which indicates good luminescence characteristics for obtaining accurate and precise ages. OSL measurements were performed on both multi-grain and single-grain aliquots. The ages obtained for the two upper archaeological levels (Itaparica) correspond to the beginning of the Holocene. Conversely, the other two archaeological levels are dated to the end of the Pleistocene. Thus, the Toca da Janela da Barra do Antonião constitutes the fifth Pleistocene-Holocene chrono-cultural sequence studied by our team in the region [2,3,4]. As such, it provides new evidence of an ancient human presence in South America, more than 20, 000 years ago.Peer reviewe