Sequence of the Cenozoic Mammalian Faunas of the Linxia Basin in Gansu, China

In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early Pleistocene. The Dzungariotherium fauna comes from the sandstones of the Jiaozigou Formation, including many representative Late Oligocene taxa. The Platybelodon fauna comes from the sandstones of the Dongxiang Formation and the conglomerates of the Laogou Formation, and its fossils are typical Middle Miocene forms, such as Hemicyon, Amphicyon, Platybelodon, Choerolophodon, Anchitherium, and Hispanotherium. ne Hipparion fauna comes from the red clay of the Liushu and Hewangiia Formations, and its fossils can be distinctly divided into four levels, including three Late Miocene levels and one Early Pliocene level. In the Linxia Basin, the Hipparion fauna has the richest mammalian fossils. The Equus fauna comes from the Wucheng Loess, and it is slightly older than that of the classical Early Pleistocene Nihewan Fauna. The mammalian faunas from the Linxia Basin provide the reliable evidence to divide the Cenozoic strata of this basin and correlate them with European mammalian sequence.