Petrography of the Upper part of Kohistan and Southern Gilgit Agency along the Indus and Kandia Rivers

Abstract

This paper present s a petrographic account of the common rocks of the previously unmapped area of Indus Kobistan and soutbwestcm Gilgit Agency. The study is based on field observations and thin sections of 55 rocks selected from OIW 200 samples quirk ly cotleacd along the lndus Valley Road
and Kandia River.
Tilt major rocks of the area are amphibolites (gneissosc mctaignccus; some banded? metasedimentary) and names-diorites (the former also having a clinopyroxene), and minor (?) alpine peridotites, granitic rocks, pegmatites, and low grade regionally metamorphosed schists in Ihe Kandia Valley. The norites-diorites are abundant in the north, the amphibolitcs in the south,
Tentative ages have been assigned to the rocks; the various igneous rocks
are considered to be related to the Himalayan orogeny and emplaced between
Middle/Late Cretaceous and Early Tertiary.
Comparison of the rock from various parts of the northern West Palistan shows that the Hornblendic Group of Mortin et al. (1962) extends from Chillas in Gilgit Agency to at least western Dir-a distance over 160 milles. There is a probability that the group may be extending in the adjacent eastern Afghanistan which is covered by the Hindukush Range. North to south, the group may occupy a territory as wide as 60 miles.