Cenozoic and Mesozoic metamorphism in the Longmenshan orogen: Implications for geodynamic models of eastern Tibet

Simon Wallis, Tatsuki Tsujimori, Mutsuki Aoya, Tetsuo Kawakami, Kentaro Terada, Kazuhiro Suzuki, Hironobu Hyodo

    Research output: Contribution to journalArticle

    93 Citations (Scopus)

    Abstract

    New zircon U-Pb and mica 40Ar/39Ar dating combined with structural studies in the Longmenshan orogen confirm that most of the upper crustal deformation in the eastern margin of Tibet is Mesozoic. However, at lower structural levels, apatite U-Pb and monazite electron microprobe dating reveals a previously unknown domain of Cenozoic (ca. 65 Ma) Barrovian-type metamorphism and deformation. This discovery shows that the crust in the eastern margin of Tibet was already a substantial thickness around the time of the India-Asia collision. Associated deformation has a N-S-oriented stretching lineation, implying that deformation was not driven by topographic gradients in the Tibetan Plateau. The observed moderate amounts of distributed postmetamorphic E-W shortening can probably explain the present thickness of the continental crust in the area. These results do not support models of crustal thickening caused by solid-state lateral flow of midcrustal metamorphic rocks.

    Original languageEnglish
    Pages (from-to)745-748
    Number of pages4
    JournalGeology
    Volume31
    Issue number9
    DOIs
    Publication statusPublished - Sep 1 2003

    Keywords

    • Cenozoic tectonics
    • Metamorphism
    • Radiometric dating
    • Tibetan Plateau

    ASJC Scopus subject areas

    • Geology

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  • Cite this

    Wallis, S., Tsujimori, T., Aoya, M., Kawakami, T., Terada, K., Suzuki, K., & Hyodo, H. (2003). Cenozoic and Mesozoic metamorphism in the Longmenshan orogen: Implications for geodynamic models of eastern Tibet. Geology, 31(9), 745-748. https://doi.org/10.1130/G19562.1