Mineralogy of the Blueschist Facies Metagraywacke from the Shergarh Sar Area, Allai Kohistan, N. Pakistan
Abstract
ABSTRACT
A new occurrence of the glaucophane bearing rock within the Indus suture zone is reported from the Shergarh Sar area in Allai Kohistan. Being composed mostly of quartz with small amount of white mica, glaucophane, chlorite and plagioclase, etc., the rock is described as blueschist facies metagraywacke. Constituent minerals are analyzed with probe; and P-T conditions of metamorphism (about 7 k-bars and 400-450oC) are calculated. Petrographic and chemical constraints of the constituent minerals oppose any retrogression or oscillatory transition in metamorphic conditions as noted in the blueschist rocks from Ladakh, and Shangla section of Swat.
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