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Jurassic paleogeography of the Tian Shan: an evolution driven by far-field tectonics and climate

Abstract : In order to decipher the paleogeographic and large-scale tectonic evolution of the Tian Shan area, we compiled three paleogeographical maps for the late Early – early Middle Jurassic, late Middle – early Late Jurassic and the Late Jurassic - Early Cretaceous transition. During the Early to early Middle Jurassic, the topographic evolution of the Tian Shan Range was dominated by the progressive planation of a late Paleozoic to early Mesozoic relief, locally interrupted by short-lived tectonic uplift. Throughout the region, the contemporaneous sedimentation was characterized by alluvial to lacustrine deposits settled under rather humid conditions. Recurrent limited deformation events associated with strike-slip and compressive tectonics occurred during this period. We propose that the Early Jurassic evolution of the Tian Shan region was related to far-field effect of the ending Qiangtang collision while its late Early to early Middle Jurassic evolution could have been driven by the subduction-related extension affecting the Caspian - Turan domains. During the late Middle to early Late Jurassic, the planation of the Paleozoic – early Mesozoic Tian Shan Range then continued. A shift to more semi-arid conditions during the Late Jurassic is also recorded in the sedimentary series all over the region. At that time, few evidences of deformation exist in the Tian Shan or within the Caspian – Turan domains. We propose that the late Middle – early Late Jurassic corresponded to a period of relative tectonic quiescence in the area. Finally, the Late Jurassic – Early Cretaceous transition was marked by a tectonic reactivation leading to the inversion of the Yarkand – Fergana Basin and to localized relief building in the Tian Shan. This period was also characterized by the climax of the aridification. We propose that this renewed transpressive deformation phase was mainly related to the accretion of the Helmand block to the south-west, and possibly to the onset of the accretion of the Lhasa Block along the southwestern margin of Eurasia.
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https://hal-insu.archives-ouvertes.fr/insu-01916011
Contributor : Isabelle Dubigeon <>
Submitted on : Thursday, November 8, 2018 - 10:47:28 AM
Last modification on : Tuesday, July 14, 2020 - 11:04:08 AM

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  • HAL Id : insu-01916011, version 1

Citation

Julien Morin, Gloria Heilbronn, Marc Jolivet, Cécile Robin, Sylvie Bourquin, et al.. Jurassic paleogeography of the Tian Shan: an evolution driven by far-field tectonics and climate. 26ème Réunion des Sciences de la terre - RST, Oct 2018, Lille, France. pp.203. ⟨insu-01916011⟩

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