Pliocene episodic exhumation and the significance of the Munsiari thrust in the northwestern Himalaya

Autor: Rasmus Thiede, István Dunkl, Djordje Grujic, Konstanze Stübner, Patricia Eugster
Rok vydání: 2018
Předmět:
Zdroj: Earth and Planetary Science Letters. 481:273-283
ISSN: 0012-821X
DOI: 10.1016/j.epsl.2017.10.036
Popis: The Himalayan thrust belt comprises three in-sequence foreland-propagating orogen-scale faults, the Main Central thrust, the Main Boundary thrust, and the Main Frontal thrust. Recently, the Munsiari–Ramgarh–Shumar thrust system has been recognized as an additional, potentially orogen-scale shear zone in the proximal footwall of the Main Central thrust. The timing of the Munsiari, Ramgarh, and Shumar thrusts and their role in Himalayan tectonics are disputed. We present 31 new zircon (U–Th)/He ages from a profile across the central Himachal Himalaya in the Beas River area. Within a ∼40 km wide belt northeast of the Kullu–Larji–Rampur window, ages ranging from to constrain a distinct episode of rapid Pliocene to Present exhumation; north and south of this belt, zircon (U–Th)/He ages are older ( to ). We attribute the Pliocene rapid exhumation episode to basal accretion to the Himalayan thrust belt and duplex formation in the Lesser Himalayan sequence including initiation of the Munsiari thrust. Pecube thermokinematic modelling suggests exhumation rates of ∼2–3 mm/yr from 4–7 to 0 Ma above the duplex contrasting with lower (
Databáze: OpenAIRE
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