40Ar/39Ar thermochronological constraints on the cooling and exhumation history of the South Tibetan Detachment System, Nyalam area, southern Tibet
Published:January 01, 2006
Yu Wang, Qi Li, Guosheng Qu, 2006. "40Ar/39Ar thermochronological constraints on the cooling and exhumation history of the South Tibetan Detachment System, Nyalam area, southern Tibet", Channel Flow, Ductile Extrusion and Exhumation in Continental Collision Zones, R. D. Law, M. P. Searle, L. Godin
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The Nyalam detachment is part of the east-west striking South Tibetan Detachment System exposed in the Nyalam area, southern Tibet. Seventeen muscovite and biotite 40Ar/39Ar age spectra and three K-feldspar multidiffusion domain modelling and cooling ages are presented for metamorphic rocks, leucogranite, granite and mylonite, collected from the Nyalam detachment and surrounding areas. The majority of the 40Ar/39Ar results are cooling ages related to exhumation, which therefore place important constraints on formation of the Nyalam detachment and exhumation history of the region. Muscovite 40Ar/39Ar ages from mylonite within the normal...
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Channel Flow, Ductile Extrusion and Exhumation in Continental Collision Zones
This collection of 27 review and research papers provides an overview of the geodynamic concepts of channel flow and ductile extrusion in continental collision zones. The focal point for this volume is the proposal that the middle or lower crust acts as a ductile, partially molten channel flowing out from beneath areas of over-thickened crust, such as the Tibetan plateau, towards the topographic surface at plateau margins. This controversial proposal explains many features related to the geodynamic evolution of the plateau and, for example, extrusion and exhumation of the crystalline core of the Himalayan mountain chain to the south. In this volume thermal-mechanical models for channel flow, extrusion and exhumation are presented, and geological and geophysical evidence both for and against the applicability of such models to the Himalayan-Tibetan Plateau system, as well as older continental collision zones such as the Hellenides, the Appalachians and the Canadian Cordillera, are discussed.