Petrotectonic framework of Siwalik Group in Khairi Murat-Kauliar area, Potwar Sub-Basin, Pakistan
Indian and Eurasian plates collision resulted in a fault-bounded Potwar sub basin. The Khairi Murat-Kauliar area lies between the Salt Range Thrust and Main Boundary Thrust. Early Eocene to Recent lithostratigraphic succession is exposed at the study area. The petrographic studies of Siwalik Group delineate different types of microfacies including feldspathic litharenite, litharenite and sub arkose. The provenance study of sandstones depicted the terrane of dissected arc and recycled orogeny, indicating that the detritus was received from sedimentary, metamorphic, plutonic and volcanic rocks from the northern domain of Indian tectonic plate, Karakoram Ranges and Kohistan Island arc. The northern edge of Indian Plate depicted a comprehensive succession of metamorphic units comprised of low-category metamorphic to upper eclogite facies. The sandstone of Siwalik Group also contains heavy mineral assemblage such as zircon, tourmaline, garnet, epidote, hornblende and chlorite. This heavy detritus assemblage depicted that the deposits were received from metamorphic and igneous origin. Field along with the petrographic inquiry revealed the consequence of Himalayan uprising and thrusting, on the depository in targeted area. The lithological fragments and average make-up of the Siwalik Group depicted different phase of Himalayan tectonics and inverted stratigraphy along with fluviatile environment of deposition.