CHARACTERIZATION OF MARBLES FROM MOHMAND AGENCY BASED ON PETROGRAPHIC, GEOCHEMICAL AND PHYSICO-MECHANICAL PROPERTIES

Abstract

This study is aimed to evaluate marbles from Nawagai Melange (Nawagai marble) exposed in Mohmand Agency. Samples were collected from four different locations, two from Ziarat, one from Spingay Tangay and one from Tora Khwa. Physical and mechanical tests were performed that include water absorption, porosity, specific gravity, bulk density, uniaxial compressive strength test, uniaxial tensile strength test, ultrasonic pulse velocity test and schmidt hammer test. Furthermore, geochemical and petrographic studies were also carried out. The obtained results were then compared with designated ASTM standards in order to establish their suitability as dimension stone. The average values for studied marble specimens were: specific gravity 2.71, water absorption 0.014 %, porosity 0.04 % and bulk density 2.70 g/cm3. Average values for mechanical tests are such that UCS 53.391 and UTS 4.46 Mega pascal (Mpa). Among non-destructive tests, average values for UPV and SH is 5057.56 m/sec and 48.75 respectively. Petrographic studies showed that all the marble varieties were pure calcitic in composition, having 0.31 to 0.35 mm average grain size. It was observed that marble which has coarser grain size (ZSW) has lower strength than the other which has a smaller grain size (ZGW, STBD and TKRW). All the investigations confirmed that the marble varieties are suitable for use as indoor dimension stone. Comparison of studied marbles (Nawagai marble) with Chitral (Gahiret marble) and Khyber marble (Mullagori) showed that they are almost same in composition but the engineering properties of current studied marble are lower than Chitral (Gahiret) and Khyber (Mullagori) marble and higher than Buner marble (Nowshera Formation).