The collision between the Yili and Tarim blocks of the Southwestern Altaids: Geochemical and age constraints of a leucogranite dike crosscutting the HP-LT metamorphic belt in the Chinese Tianshan Orogen.
Gao J, Klemd R, Qian Q, Zhang X, Li J, Jiang T, Yang Y (2011)
Publication Type: Journal article
Publication year: 2011
Journal
Publisher: Elsevier
Book Volume: 499
Pages Range: 118-131
DOI: 10.1016/j.tecto.2011.01.001
Abstract
A ca. 600m-long, 0.5-20m-wide NW-SE trending granite dike crosscuts the high pressure-low temperature (HP-LT) Tianshan metamorphic belt, the foliation of which is parallel to the main ENE regional trend in the Chinese South Tianshan Orogen. It is mainly composed of plagioclase, K-feldspar, quartz, muscovite, biotite and secondary chlorite, while fluorite, zircon and xenotime occur as accessories. The immediate country rock is a quartz-biotite-plagioclase schist, which grades several tens of meters away from the granite dike into a chlorite-mica-albite schist. The latter schist is intimately intercalated with blueschist layers and boudins. The A/CNK value of the granite dike samples varies from 1.15 to 1.27 indicating a strongly peraluminous composition. CaO/Na2O ranges from 0.06 to 0.17 and Al2O3/TiO2 from 240 to 525, similar to the ratios of strongly peraluminous (SP) granites exposed in 'high-pressure' collision zones such as the Himalayas. A zircon U-Pb age of 285Ma was obtained for the granite dike, thus constraining the upper limit for the age of HP-LT metamorphism. The petrological and geochemical data suggest that the SP leucogranite dike intruded during the exhumation of overthickened crust in the post-collisional setting between the Yili (-Central Tianshan) and Tarim blocks. The dataset presented here in conjunction with previously published data corroborate that the HP-LT metamorphism must have occurred earlier than the Permian in the Tianshan Orogen. Therefore, the collision between the Yili (-Central Tianshan) and Tarim blocks and the final amalgamation of the Southwestern Altaids must have been terminated in Late Paleozoic and not in Triassic times as previously suggested. © 2011 Elsevier B.V.
Authors with CRIS profile
Involved external institutions
China University of Geosciences / 中国地质大学
China (CN)
Chinese Academy of Sciences (CAS) / 中国科学院
China (CN)
China (CN)
Chinese Academy of Sciences (CAS) / 中国科学院
China (CN)
How to cite
APA:
Gao, J., Klemd, R., Qian, Q., Zhang, X., Li, J., Jiang, T., & Yang, Y. (2011). The collision between the Yili and Tarim blocks of the Southwestern Altaids: Geochemical and age constraints of a leucogranite dike crosscutting the HP-LT metamorphic belt in the Chinese Tianshan Orogen. Tectonophysics, 499, 118-131. https://doi.org/10.1016/j.tecto.2011.01.001
MLA:
Gao, Jun, et al. "The collision between the Yili and Tarim blocks of the Southwestern Altaids: Geochemical and age constraints of a leucogranite dike crosscutting the HP-LT metamorphic belt in the Chinese Tianshan Orogen." Tectonophysics 499 (2011): 118-131.
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