Mio-Pleistocene Zanda Basin biostratigraphy and geochronology, pre-Ice Age fauna, and mammalian evolution in western Himalaya

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t a r t i c l e i n f o The Pliocene (5.3–2.6 Ma) of Tibet witnessed the drying of the northern Tibetan Plateau and the approach to the Pleistocene Ice Age within the background of intensifying Indian and East Asian monsoons. Yet little is known about Pliocene mammals living on the high Tibetan Plateau despite the fact that fossil mammals elsewhere constitute an important knowledge base for terrestrial environments. The late Miocene to Pleistocene Zanda Basin at the northern foothills of the Himalayas affords a welcome opportunity to evaluate the biological response to environmental change at high elevations. Abundant, well-preserved fossil mammals and fish from an 800-m continuous section of fine-to coarse-grained sediments thus open a rare window into a past biological world. For example, the discovery of an ancestral wooly rhino from Zanda Basin that was the precursor of its late Pleistocene megafaunal descendants leads to our " out-of Tibet " hypothesis, suggesting that the high Tibetan Plateau was a Pliocene cradle for Ice Age cold adaptations. In this paper, we document in detail the mammalian biostratigraphy, chronology, and paleozoogeography based on Zanda Basin fossil mammals. Our high-resolution biostratigraphy and biochronology offer for the first time independent constraints that both support and modify recent magnetostratigraphic correlations. Using characteristic Pliocene and Pleistocene mammals, particularly the small mammal assemblages in the lower part of the section and monodactylid Equus from the upper section, we propose a correlation to C1n to C3An.1r, with an age range of ~400 Ka to 6.4 Ma. Within the 800-m Zanda section, the lower 0–150 m is of latest Miocene age, spanning 6.4–5.3 Ma. Sparsely fos-siliferous, the lower section has produced five taxa so far: Ochotona, Panthera, Qurliqnoria, Palaeotragus, and Hipparion—all are consistent with a late Miocene age. The middle 150–620 m section spans the entire Pliocene. In the upper 620–800 m section the fossils are rare, but do include characteristic Pleistocene taxa such as Equus. Zoogeographically Zanda Basin mammals are a mixture from two major sources. Xenocyon are commonly found in north China or east Asia. In contrast, several forms, such as unique species of pikas …