Geochemical exploration in the Dir and Swat Kohistan, northern Pakistan
Abstract
The Dir and Swat Kohistan cover an area of about 10,000 sq. Km in northern Pakistan. The major portion of the study area is comprised of rocks of the Kohistan Island arc while the rest of the area is composed of the rocks of the Indo-Pakistan plate. Both these terrains are separated by the Indus suture melange zone, which represents the collision suture between the Indo-Pakistan and Eurasian plate.
Initial identification and delineation of mineral anomalies in the Dir and Swat Kohistan has been carried out by using heavy-mineral panned concentrates and stream sediment sampling from various drainage basins. Mineralogical studies of the heavy mineral concentrates suggest the presence of gold in the form of piece, speck and color in certain drainage basins, however, no nugget of gold has been found.
The samples of both heavy-mineral concentrates and stream sediments have been analyzed for Cu, Zn, Pb, Cr, Ni, Mo, Sn, W, As, Sb, Bi, Ba, Th, U, Au, Ag and Pt by ICP-MS and AA techniques. These elements were processed by the geostatistical map analysis technique to: (a) display broad-scale regional distribution of the elements on the basis of single element consideration (b) delineate anomalous areas of most interest for further follow-up. Some of the elements, especially Au, Ag and Pt, show high anomalous values in heavy-mineral panned concentrates which could be related to a specific mineralization either within the Indus suture melange zone or Indo-Pakistan plate. The present study suggests that the areas proximal to the Indus suture have potential for gold, silver, platinum and base metal mineralization. Detail geochemical mapping in these areas is, therefore, recommended for further follow-up.
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