Stable carbon and oxygen isotopes as environmental indicators of the Late Pleistocene in El Arenoso, Sonora, Northwest Mexico

The paleoenvironment conditions that existed in the Late Pleistocene at the archaeological-paleontological site of El Arenoso, Sonora, NW Mexico, were inferred using the carbon and oxygen stable isotopes from one bison, one mammoth, and thirteen horses as well as the pedological characteristics and the carbon isotopes of calcium carbonates from paleosoil. The values delta C-13 of the bison (-1.4 parts per thousand), the horses (-2.8 parts per thousand), and the mammoth (-4.3 parts per thousand) show that these animals fed mainly on C, plants and carbon isotopic values from profile horizons of locality 4Bgk (-3.4 parts per thousand), 3Ck (-3.4 parts per thousand), and 2Bgk2 (-5.7 parts per thousand) indicated the presence of C-3/C-4 vegetation mixed in El Arenoso. The oxygen isotopic ratios of the bison (-4.3 parts per thousand), the horses (-2.6 parts per thousand), and the mammoth (-5.1 parts per thousand) show that these animals inhabited an arid environment, consistent with the results from the analyses of paleosols.