Earth Science Frontiers ›› 2022, Vol. 29 ›› Issue (2): 241-260.DOI: 10.13745/j.esf.sf.2021.10.39

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Granitic magmatism and tectonic evolution in the Qilian Mountain Range in NW China: A review

ZHU Xiaohui1,2(), CHEN Danling2,*(), FENG Yimin1, REN Yunfei2, ZHANG Xin1   

  1. 1. Research Center for Orogenic Geology, Xi’an Center of Geological Survey, China Geological Survey, Xi’an 710054, China
    2. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an 710069, China
  • Received:2021-06-07 Revised:2021-08-30 Online:2022-03-25 Published:2022-03-31
  • Contact: CHEN Danling

Abstract:

The Qilian Mountain is a composite orogenic belt that has experienced multicyclic tectonic movements, and granitic magmatism plays an important role in the tectonic evolution of such an orogenic belt. According to zircon U-Pb geochronology results, granitic magmatism in the Qilian Mountain can be divided into seven major stages. The Early Paleoproterozoic (2470-2348 Ma) granitic magmatism is related to high-K calc-alkaline strongly peraluminous S-type granites and tholeiitic to high-K calc-alkaline metaluminous I-type granites, which recorded the crustal accretion and transformation events of this period. The Late Paleoproterozoic (1778-1763 Ma) granitic magmatism is predominantly associated with high-K calc-alkaline shoshonitic metaluminous to weakly peraluminous A-type granites formed as a result of the breakup of the Columbia supercontinent. The Late Mesoproterozoic to Early Neoproterozoic (1192-888 Ma) granitic magmatism is mainly related to calc-alkaline shoshonitic peraluminous to strongly peraluminous S-type granites, while the Middle Neoproterozoic (853-736 Ma) granitic magmatism is primarily associated with calc-alkaline to high-K calc-alkaline metaluminous to strongly peraluminous A-type granites, and, respectively, they correspond to the assembly and breakup of the Rodinia supercontinent. The Middle Cambrian to Silurian (516-419 Ma) granitoids are formed during ocean-continent transition, whilst the widely distributed low-Mg adakites (Ca. 440 Ma), derived from the partial melting of thickened crust, indicate the Qilian orogenic belt had fully entered the collisional orogenic period. The Devonian to Early Carboniferous (418-350 Ma) granitoids are formed in the post-collisional environment and consist a series of granites with rock types ranging from tholeiitic to shoshonitic, metaluminous to strongly peraluminous. The Middle Permian to Late Triassic (271-211 Ma) granitoids are dominated by calc-alkaline to high-K calc-alkaline metaluminous to weakly peraluminous I-type granites, with small amounts of high-K calc-alkaline weakly peraluminous A-type granites; respectively, these two types are associated with oceanic subduction and post-collisional extension.

Key words: geochronology, geochemistry, spatial-temporal distribution, granite, Qilian Mountain

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