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Polarity and Timing of the Deformation along the Jinsha Suture Zone (Yushu area, Northeastern Tibet)
  • +6
  • Fanny Goussin,
  • Stéphane Guillot,
  • Gilles Ruffet,
  • Marc Poujol,
  • Émilien Oliot,
  • Anne Replumaz,
  • Carole Cordier,
  • Guillaume Dupont-Nivet,
  • Pierrick Roperch
Fanny Goussin
ISTerre
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Stéphane Guillot
ISTerre, CNRS, Université Grenoble Alpes

Corresponding Author:[email protected]

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Gilles Ruffet
French National Centre for Scientific Research
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Marc Poujol
Université Rennes 1
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Émilien Oliot
UMR 5243 Géosciences Montpellier, CNRS, Université de Montpellier, 34095, Montpellier Cedex 05, France
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Anne Replumaz
ISTerre, Université Grenoble Alpes
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Carole Cordier
Universita degli Studi di Siena
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Guillaume Dupont-Nivet
French National Centre for Scientific Research (CNRS)
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Pierrick Roperch
Géosciences Rennes
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Abstract

The Tibetan Plateau was formed by intense Cenozoic shortening (up to 1100 km) of a composite “proto-Tibet”, itself the product of a long Paleozoic and Mesozoic history of accretion of Gondwana-derived continental fragments and volcanic arcs against the Asian continental margin. The difficult access and the scarcity of outcrops have long limited the possibilities of studying these Mesozoic suture zones in the heart of the Plateau. In this work, we present new U-Pb and 40Ar/39Ar ages from the highly deformed units of the Yushu mélange, along the Jinsha Suture in the northeastern Qiangtang terrane. Early Triassic (c. 253 Ma) to Middle Jurassic ages (c. 165 Ma) complement the existing dataset and help to refine the chronology of the Paleo-Tethyan oceanic subductions which have structured the northeastern part of the Qiangtang terrane. The Yushu mélange records at least three successive tectono-magmatic events. The opening of a back-arc basin during the northward Paleo-Tethyan subduction along the Longmu Co-Shuanghu Suture during Early to Middle Triassic; then its closure during the southward subduction of the Songpan-Ganze Ocean along the Jinsha Suture in Late Triassic. Finally, a shortening phase related to the continental collision of the Songpan-Ganze and Qiangtang blocks from Late Triassic to Early-Middle Jurassic. No evidence for any high- or mid-temperature Cenozoic reactivation of the Jinsha suture in our study area is recorded.
01 May 2023Submitted to ESS Open Archive
02 May 2023Published in ESS Open Archive