ALBITE PORPHYROBLAST BEARING BASIC SCHISTS IN THE SHYOK SUTURE ZONE, LADAKH HIMALAYA, NW INDIA

Abstract

The Shyok suture zone in Ladakh Himalaya, NW India separates the Asian plate in the north from the Kohistan-Ladakh island arc in the south. The albite porphyroblast bearing basic schists occurring in the zone have a mineral assemblage of amphibole, albite, epidote, zoisite, clinozoisite, chlorite, calcite, quartz and opaques that are fine-grained except for albite. The albite porphyroblasts appear normally in a zone of 30cm to 1m wide and most of them occur as lens-shaped grains with pressure solution edges, of which the grain size is 1-3mm. They occur generally as aggregates of smaller albite grains. The schists record the low pressure and temperature condition or the lower greenschist facies. There is no record suggesting any high-pressure conditions so far.