Metamorphism and Structural Interpretation of the Zanskar Shear Zone, PJW Himalaya, India

Herren in 1987, reported normal faults resulted in the telescoping of metamorphic isograds within a 200 meter zone between Sumche Topko to Mulung Topko in the Zanskar Shear Zone NW Himalaya. However petrographic study-of sections obtained from Mulung Topko and surrounding areas (pensila-padarn section) indicate that the rocks belong to the kyanite-sillimanite-starurolite grade only. Extension crenulation cleavage and other shear criteria show an initial NESW movement after which a layer parallel extension occurred and the shear zone developed. Minieralogical assemblage and mapping indicate that the isograds run paralleI to each other before they possibly truncate against the shear zone along the Pensila-Padam section. A probable model has been proposed to explain the features.