1 Age and Anatomy of the Gongga Shan Batholith, Eastern Tibetan
Age and Anatomy of the Gongga Shan batholith, Eastern Tibetan Plateau and its relationship to the active Xianshui-he fault. M.P. Searle1, N.M.W. Roberts2, S-L. Chung3,4, Y-H. Lee5, K.L. Cook3,6, J.R. Elliott1, O.M. Weller7, M.R. St-Onge7, X. Xu8, X. Tan8, and K. Li8. 1. Department of Earth Sciences, Oxford University, South Parks Road, Oxford OX1 3AN, UK. 2. NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, UK. 3. Department of Geosciences, National Taiwan University (NTU), Taipei 10617, Taiwan. 4. Institute of Earth Sciences, Academia Sinica, Taipei 11529, Taiwan. 5. Department of Earth and Environmental Sciences, National Chung-Cheng University, Chiayi, Taiwan. 6. Now at: GFZ German Research Center for Geosciences, Telegafenberg, 14473 Potsdam, Germany. 7. Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada. 8. Institute of Geology, China Earthquake Administration, Huayanli A1, Chaoyang district, Beijing 100029, China. 1 Abstract The Gongga Shan batholith of eastern Tibet, previously documented as a ~32 – 12.8 Ma granite pluton, shows some of the youngest U-Pb granite crystallisation ages recorded from the Tibetan plateau, with major implications for the tectonothermal history of the region. Field observations indicate that the batholith is composite, with some localities showing at least seven cross-cutting phases of granitoids that range in composition from diorite to leucocratic monzogranite. In this study we present U-Pb ages of zircon and allanite dated by LA-ICPMS on seven samples, to further investigate the chronology of the batholith. The age data constrain two striking tectonic-plutonic events: a complex Triassic-Jurassic (ca.
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