Imprints of transpressional deformation on the southern Kohat Plateau, Karak area, NW Himalayas, NWFP, Pakistan
Abstract
A suite of evaporite deposits, shelf sediments and mollase sequence of Early Cenozoic age from Karak area marks a part of southern Kohat Plateau. Structurally the area is interpreted as east-west trending positive flower structure, which is exposed for about 20 km along strike with widths varying from 3-5 km laterally. It is bounded by the north dipping Karak Fault in the south and south dipping Nari Panos Fault in the north and internally subdivided by the south dipping Banda Kunghara Fault. All these faults trend east-west and have moderate surface dips. A right lateral component of deformation along the Karak-Nari Panos structure is indicated by: I) the north-east directed trend of the Daggar Syncline in the footwall of the Nari Panos Fault, 2) the local scale thrusts in the core of this syncline and 3) east north east trending right stepping folds located south-east of Banda Charpara in the footwall of Banda Kunghara Fault. The idea of transpressional deformation is also supported by the seismic data, which shows that all the major fault structures become steep, converging at deeper level and the presence of horizontal to sub-horizontal slicks on different fault surfaces. The region has experienced an early phase of compressional deformation overprinted by later phase of transpressional deformation of Plio-Pleistocene age.
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