Tectonics of Nanga Parbat, western Himalaya: Synkinematic plutonism withinthe doubly vergent shear zones of a crustal-scale pop-up structure

Detailed mapping and geochronologic investigations from the eastern, southe rn, and western Nanga Parbat-Haramosh massif reveal two thrust-displacement shear zones that have a spatial and temporal link with granite plutonism f rom ca. 10 to 1 Ma. The shear zones define a crustal-scale antiformal pop-u p structure, with dominant west-northwest-vergent and subordinate east-sout heast-vergent thrusting. This is substantially different than the surroundi ng area where the main exposed Himalayan structures are oriented parallel t o the orogenic trend and are early to middle Miocene or older Structures ma pped throughout Nanga Parbat demonstrate that its rapid and young exhumatio n is not due to orogen-scale structural unroofing, and that sustained high erosion rates are required. The observed west-northwest-directed shortening is proposed to be a result of differential arc-parallel motion accommodate d at the syntaxial bend of the northwest Himalaya.