Has late Cenozoic climate change lead to enhanced erosion in the Kyrgyz and Chinese Tien Shan?

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A fundamental question and the primary goal of this study is deciphering the interplay of climate and tectonics in the evolution of mountain belts, in particular, whether late Cenozoic climate change has led to enhanced erosion. We propose to test this hypothesis in the Kyrgyz and Chinese Tien Shan using thermochronology. Higher temperature methods (apatite fission track, U-Th/He on zircon) will be used to establish the onset and propagation of exhumation of several ranges; lower temperature methods (U-Th/He on apatite) will then be used to test if these regions experienced an enhanced episode of exhumation in the last 5 Ma. Structural geology and mapping will aid in determining the magnitude and mechanisms of exhumation. This will provide a thorough understanding of the late Cenozoic development of the orogen. Determining whether such a young pulse of tectonism is spatially and temporally synchronous or asynchronous and comparing this record with the previous history will allow the differentiation between tectonic and climatic driving factors that influence deformation and uplift. The second goal of this project is to characterize the Cenozoic tectonic growth of the Tien Shan, a broken foreland comprised of basement uplifts akin to the North and South American Laramide and Sierras Pampeanas morphostructural provinces, respectively. At present, seismicity and shortening are distributed throughout the width of the orogen; however, shortening commenced on the southern margin of the mountain belt and migrated northwards.