Nappe tectonics, extension, and metamorphic evolution in the Indian Tethys Himalaya (Higher HImalaya, SE Zanskar and NW Lahul)

Abstract

In the southern part of the Indian Tethys Himalaya between SE Zanskar and NW Lahul, nappe tectonics with transport toward the WSW during the main deformation phase has been ascertained. If the stratigraphy of the different units considered as nappes is combined, it results in a composite section ranging from lower Cambrian to Middle Cretaceous. A metamorphism of amphibolite facies in the lowest unit is associated with the nappe stacking. The Lower Miocene cooling ages of metamorphic biotite and muscovite suggest that the nappe emplacement starts at the Oligocene, or at the Oligocene‐Eocene boundary. After the compressional phases, an extension provokes the reactivation of older main thrusts as normal fault and the formation of a steeply dipping normal fault. This interpretation is based on detailed mapping.