Petrography and geochemistry of sandstone of the kamlial formation, islamabad expressway section, islamabad,

Abstract

The area of investigation is exposed along the Express Highway Islamabad near Korang Bridge. The Miocene Rawalpindi Group including the Kamlial and Murree formations and Quaternary deposits are exposed. The Kamlial Formation, which is the focus of this study contains abundant quartz, which is fractured and oriented as microlenses along with K-feldspar as microcline, micro-perthithe, orthoclase and sanidine, and albite to andesine plagioclase feldspar indicating felsic plutonic and volcanic rocks protoliths. Besides, the presence of pyroxenes and amphiboles also indicate mafic volcanic and or plutonic rocks source. Traces of garnet, epidote, chlorite, biotite, muscovite, vermiculite may show metamorphic origin of the clasts. The orientation of the grains and bending in mica indicates that the formation has undergone through deformation due to shearing. Based on geochemistry, the sandstone of the Kamlial Formation is mainly litharenite which shows fluvial depositional environment. It illustrates recycle oceanic island arc tectonic origin and provenance of Himalaya and Kohistan Island arc.