Outline geological map of the Nanga Parbat-Haramosh Massif

Granitoid and metasedimentary gneisses of the Indian continental basement form the core of the NPHM. They are mantled by metasedimentary rocks derived from the pre-collisional passive margin cover of India. Along the eastern, northern and southwestern portions of the margin, rocks of the Kohistan-Ladakh island arc suite contact these across the mylonites of the Main Mantle Thrust [MMT], which has been distorted by the rise of the NPHM into a large crustal-scale antiformal fold. This antiformal structure has been modified by overthrusting to the NW along the central part of the western margin [Raikot-Liachar Thrust]. The regional antiform is more complex in detail, with two recognisable antiforms separated by a zone of mylonites, including pelitic schist and amphibolite. In the Astor River section, the mylonites form a “pinched” syncline, characteristic of basement-cover contacts. We interpret this newly recognised zone to connect with the Rupal-Chhichi Shear Zone south east of Nanga Parbat peak. This zone of east/southeast-directed thrusting combines with the Raikot-Liachar Thrust on the western margin of the NPHM to produce a large-scale “pop-up” structure for the core of the NPHM.

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