The Tectonics of the Tso Morari Ultra High Pressure Nappe in Ladakh, NW Indian Himalaya

Abstract

A tectonic model for the structural development of the Tso Morari ultra-high pressure nappe is proposed. It is integrated into the context of the formation of the North Himalayan nappes of the Ladakh Himalaya. In the area, this stack of nappes is composed by, from base to top, the Tso Morari, Tetraogal, Karzok ophiolite, Nyimaling-Tsarap and Mata nappes (Steck et al. 1998, Steck 2003). Four stretching lineations, L1 – L4, are successively developed on the main schistosity in the North Himalayan nappes (Epard and Steck 2008). L1, with its top-to-the E shear indicators, was formed during the W-directed high temperature extrusion of the ultra high pressure Tso Morari nappe. L2, with its top-to-the S shear indicators, was formed during an early N-directed underthrusting of India below Asia. It is developed in the roof of the Tso Morari nappe as well as at the base and frontal part of the Nyimaling-