ESR dating of Smilodon populator from Toca de Cima dos Pilao, Piaui, Brazil

摘要

Smilodon is a genus of big cats that lived from the early to the late Pleistocene in regions extending from North to South America. The fossil records of the "saber-toothed cats" are uneven, with some taxa being quite abundant in certain regions. In Brazil, Smilodon populator is a well-known species whose remains, although scarce in comparison to other large mammals, are found all across the country. In particular, there are multiple records of this species in the region of the Serra da Capivara National Park. This area was home to a rich Pleistocene-Holocene fauna, including many mammals. Here, we report on the Electron Spin Resonance dating of a Smilodon populator tooth found in "Toca de Cima dos Pilao", located in the surroundings of the Serra da Capivara National Park. The equivalent dose found after exponential fitting of dose-response curve was (2.7 +/- 0.3)x10(2) Gy. Neutron Activation Analysis was used to determine the concentration of radioisotopes present in the sample and in the sediment to calculate the internal and external dose rates. The result of age found is 93 +/- 9 ka, which confirmed the presence of this species in Serra da Capivara National Park in the late Pleistocene.