A revised chronology of the lowest occupation layer of Pedra Furada Rock Shelter, Piauı́, Brazil: the Pleistocene peopling of the Americas

摘要: Abstract The present work revisits the chronology of archaeologically controversial Pedra Furada Rock Shelter Southeast Piaui, Brazil, using an improved radiocarbon laboratory pre-treatment and measurements on charcoal samples. procedure, known as ABOX-SC (acid–base–wet oxidation followed by stepped combustion), has previously been used to secure dates >40 ka for antiquity human occupation Australia South Africa, now applied from dated oldest layer site. Previous dating had obtained only lower limits 40–45 ka BP basal layer. Nine samples well-structured hearths were subjected procedure their content determined accelerator mass spectrometry. Measurements five returned ages greater than 56 ka BP, graphites produced ABOX pre-treated combusted at 910°C. Two other 50 ka BP. remaining two essentially completely 650°C, with no material surviving make a 910°C CO 2 fraction. Their 41.3 47.2 ka Ages generated 650°C fraction are considered minimum ages.