Petrographic, Geochemical and Physio-mechanical investigation of granitic rocks exposed in Dir-Bajaur granitic belt, Jandool valley, Lower Dir, KPK, Pakistan

Abstract

The Dir-Bajuar granitic belt located along the north-west political boundary in Lower Dir Jandool, KPK between Pakistan and Afghanistan having variety of granitic rocks currently mining for dimension stone and other ornamental purposes. The rocks exposed in Dir-Bajaur granitic belt are mostly granitic in nature which is studied in term of petrographic observations, geochemical analysis and physio-mechanical investigation. The texture of the rocks exposed in Dir-Bajaur granitic belt are from medium to coarse grain porphyritic nature. The granitic rocks of the area show calc-alkaline to per aluminous character. The tectonic environment of the belt is probably considered to be syn-collisional by different plots of Sio2 against major and trace elements. Keeping in view the geochemical characteristics and petrographic observations reveals that the rocks are showing resemblance to Ambela granite, Utla granite Gadoon, and Mansehra granites. The resembling characteristics includes the presence of porphyritic texture and calc-alkaline geochemical signatures. The physio-mechanical investigation includes unconfined compressive strength (UCS), unconfined tensile strength (UTS), specific gravity, loss angles abrasion, water absorption, gradation (sieve analysis) for both fine and coarse, and sand equivalent. These properties determined that the rocks of Dir-Bajaur granitic belt are moderately strong and resistive to erosion and abrasions and are suitable dimension stone industry. The medium grained texture of the granite gives an additional enhancement to the hardness of the rocks.