INVESTIGATION OF PETROGRAPHIC AND GEOMECHANICAL CHARACTERISTICS OF SELECTED ROCKS FROM SHEWA SHAHBAZ GHARI COMPLEX, NORTH WEST PAKISTAN

Abstract

The current research work is focused on the physical, mechanical and petrographic investigation of igneous and metamorphic rocks exposed in Shewa Shahbaz Ghari Complex, North Pakistan. The bulk samples were collected from the study area and geological features were noted including grain size, weathered and fresh surfaces at exposed outcrops. The collected samples include Metamorphosed Gabbro (MB), Gabbro (G), Metamorphosed Rhyolite (MR), Granodiorites (GD) and Dolerite (D). For petrographic studies thin sections were prepared by cutting and polishing of slabs recovered from each bulk sample. Four cubes were prepared from the collected bulk samples of each variety of rock to determine its physical properties (specific gravity, water absorption and porosity) and mechanical strength (unconfined compressive strength and Los Angeles abrasion value). Petrographic studies indicate that the major minerals are pyroxene, quartz and amphibole. Further investigations indicate that the presence of minerals i.e., pyroxene, quartz and amphibole, improves the mechanical strength of rock. The UCS values of all the collected samples fall in the category of “High” strength rock according to ISRM, 1981. The results of physical and mechanical properties of Shewa Shahbaz Ghari Complex satisfies the standard requirements and therefore it can be used as a construction material and as an aggregate material in road construction.