Zircon SHRIMP U-Pb ages of the Gangdese Batholith and implications for Neotethyan subduction in southern Tibet

Da Ren Wen, Dunyi Liu, Sun Lin Chung*, Mei Fei Chu, Jianqing Ji, Qi Zhang, Biao Song, Tung Yi Lee, Meng Wang Yeh, Ching Hua Lo

*此作品的通信作者

    研究成果: 雜誌貢獻期刊論文同行評審

    425 引文 斯高帕斯(Scopus)

    摘要

    The Trans-Himalayan magmatism, which occurred extensively in the Lhasa terrane of southern Tibet, has long been related to the Neotethyan subduction before the India-Asia collision. To better delineate the magmatic duration, we report a geochronological study with 25 SHRIMP zircon U-Pb ages from the Gangdese Batholith that represents the largest Trans-Himalayan plutonic complex. The results suggest two distinct stages of plutonism in the Late Cretaceous (ca. 103-80 Ma) and early Paleogene (ca. 65-46 Ma), respectively. Our new data confirm if not refine the notion that a Gangdese magmatic gap or quiescent period existed between ca. 80 and 70 Ma. It is furthermore identified that the early stage ended with adakitic intrusion and the latter stage is marked by a peak activity at ca. 50 Ma. We attribute the cessation of the early stage, and following magmatic gap, to a flattening of the northward Neotethyan subduction, and the initiation of the latter stage to rollback of the subducted slab. The proposed scenarios can also account for the southward migration and intensification of Cretaceous to Paleogene volcanism in the Lhasa terrane that demonstrates a coeval, eruptive "flare-up" event around 50 Ma, interpreted as the result of detaching the Neotethyan oceanic slab from the adherent, more buoyant Indian continental lithosphere owing to the India-Asia collision. Our model is, moreover, in general accord with sedimentary and structural geologic records from southern Tibet where subduction-related orogenesis appears to have evolved through time before India started colliding Asia.

    原文英語
    頁(從 - 到)191-201
    頁數11
    期刊Chemical Geology
    252
    發行號3-4
    DOIs
    出版狀態已發佈 - 2008 七月 15

    ASJC Scopus subject areas

    • 地質學
    • 地球化學與岩石學

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