Extension of Skhakot-Qila Ultramafic Complex in Utman Khel, Mohmand Agency, N.W.F.P., Pakistan

Abstract

The Utman Khel area in Mohmand Agency contains bodies of ultramafic and mafic rocks covering an area more than one third of that of the Utman Khel mountains. The ultramafic rocks are emplaced as klippe over the metasediments of Paleozoic age. The central part of the complex generally consists of massive dunite, peridotite, and grades outward into massive to friable serpentinites. At several places, dunite, peridotite, and serpentinite are altered to talc-carbonate and carbonate-quartz rock, particularly along shear zones. Steatite and blackwall-chlorite rock form small masses at the margins of the ultramafic rocks, adjacent to the contact with metasediments. Chromite occurs as podlike and lensoidal masses in 54 showings sporadically distributed over six different locations. The characteristics displayed by the ultramafic rocks of the Utman Khel a m are virtually similar to those displayed by the rocks of the Skhakot-Qila complex. Therefore, it is appropriate to consider the ultramafic rocks of Utman Khel area as the extension of Skhakot-Qila Complex.