Collaborative Research: Vertebrate Paleontology and Paleoenvironments of the Richest, Endemic-Dominated Vertebrate Assemblage in Cenozoic of Qaidam Basin, Tibetan Plateau, China

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ABSTRACTThis is a multi-national, multidisciplinary research project to survey Cenozoic fossils in the northern Tibetan Plateau. Due to difficulties of access and extreme environments, the vast plateau is little explored and remains the last frontier for paleontological explorations. Preliminary surveys in the Qaidam basin, the largest terrestrial basin in the Tibetan Plateau, have yielded a number of richly fossiliferous localities spanning a long sequence of strata often more than 5,000 meters thick in continuous exposures. Ranging from early Miocene (about 24 to 16 million years ago) to Pliocene (about 5 to 2 million years ago), such a remarkably complete record reveals much that was previously unknown to science. A team of paleontologists, structural and sedimentary geologists, isotope geochemists, and paleomagnetists is systematically collecting fossil mammals, fishes, and plants in the Qaidam basin and studying their paleoenvironments. Combined with paleomagnetic studies, the fossils help to establish the ages of the rocks in which they are preserved. Sedimentologic studies on the river, lake, and over-bank deposits also provide further evidence for the sources of the sediments from the surrounding mountains, the nature of the paleodrainages, and the evolution of the basin history. Analyses of carbon and oxygen isotopes preserved in fossil mammalian teeth provide valuable information about animals' diets (whether they were leave browsers or grass grazers), environment (whether they lived in a forest or on a grassland or in a wooded grassland), and regional climate. By integrating the paleontologic, magnetic, sedimentary, and geochemical data, we hope to achieve a better understanding of the links between the uplift of the Tibetan Plateau and the late Cenozoic environmental and biotic changes. Comparisons of faunas from the southern slope of Tibet in India and Pakistan with the Qaidam faunas to the north will offer clues of mammalian migrations and geographic barriers as the high Tibet continued to rise. The new data are particularly relevant in the current debate over the impact of the rising Tibetan Plateau on climate, vegetation, and mammalian evolution in the Cenozoic of Eurasia.