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Abstract

This paper documents the occurrence of alkaline-igneous complex, which is exposed 30 km northwest of Peshawar, near Michni (Mohmand Agency), N.W.F.P. The complex appears to be the eastern extension of the Warsak alkaline rocks and is considered to be the part of the alkaline igneous province of the Peshawar plain. It shows a series of rock associations, such as mica-pyroxenite, melteigite and ijolites occur in the inner horizon, whereas the outer sequence contains nepheline-syenite and alkali-syenite. The foidal syenite and alkali syenite occur as lensoidal bodies within the inner horizon. Petrographic study of these rocks clearly show reaction rims in and around pyroxene and foidal minerals indicating metasomatism and/or alteration.