1. Exhumation History Along the Muli Thrust—Implication for Crustal Thickening Mechanism in Eastern Tibet
- Author
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Pitard, P., Replumaz, A., Chevalier, M. L., Leloup, P. H., Bai, M., Doin, M. P., Thieulot, C., Ou, X., Balvay, M., Li, H., Mantle dynamics & theoretical geophysics, Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Institute of Geology [Beijing], Chinese Academy of Geological Sciences [Beijing] (CAGS), Ministry of Land and Resources (MLR)-Ministry of Land and Resources (MLR), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Utrecht University [Utrecht], Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Grenoble Alpes (UGA)-Université Gustave Eiffel-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), and Mantle dynamics & theoretical geophysics
- Subjects
010504 meteorology & atmospheric sciences ,[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] ,Earth and Planetary Sciences(all) ,Thrust ,Fault (geology) ,010502 geochemistry & geophysics ,01 natural sciences ,Flattening ,Tibetan Plateau ,Muli thrust ,low-temperature thermochronology ,0105 earth and related environmental sciences ,Décollement ,geography ,geography.geographical_feature_category ,Crust ,Thermochronology ,Geophysics ,Shear (geology) ,General Earth and Planetary Sciences ,Shear zone ,formation Tibet ,crustal structure of Tibet ,Geology ,Seismology ,Yalong thrust belt - Abstract
International audience; The eastern margin of the world's largest and highest orogenic plateau, the Tibetan Plateau, shows contrasted edges, with a steep topographic gradient along the Longmen Shan (LMS) north of the Xianshuihe strike-slip fault (XF), and gentler slopes across the Yalong margin to the south (Figure 1a). The driving mechanism(s) leading to such contrasts between margins are still poorly understood and have given rise to end-member models of plateau growth with different crustal structures: either a weak lower crust localizing crustal thickening ("channel flow model," e.g., Clark & Royden, 2000), or a more rigid crust, with thickening that includes the upper crust, in a brittle manner ("stepwise model," Tapponnier et al., 2001). Those two end-member models can be tested by investigating the role of thrusting mechanisms in SE Tibet. At present, upper crustal deformation of the LMS is dominated by reverse faulting with a small component of right-lateral motion, as shown by recent earthquake focal mechanisms such as that of the 2008 Mw7.9 Wenchuan earthquake (e.g., de Michele et al., 2010; Fielding et al., 2013). This event ruptured two subparallel reverse structures, the Guanxian and Beichuan thrusts (Figure 1b), with steep shallow ramps (up to 70°) which root between 15 and 25 km-depth on a sub-horizontal décollement zone (e.g.
- Published
- 2021