Nilawahan Rift, a Permian event in Salt Range, Pakistan
Abstract
New data on a volcanic glass beds interbedded with Warcha Sandstone of Nilawahan Group in Eastern Salt Range is presented. Major, trace and rare earth element data on these volcanic rocks clearly points towards highly alkaline nature of the volcanicity. Nilawahan group of Salt Range and associated alkaline volcanic rocks suggest that these rocks were deposited/extruded in a rift system which was developed during the Permian rifting of Gondwanaland. This rift is proposed to be designated as NILAWAHAN RIFT. Nilawahan Rift was a low volcanicity failed rift (aulcogene) of the Gondwana Rift belt with a nearly NS orientation in a Gondwanic configuration. The northern parts of the rift recorded marine transgression as evidenced by Permian limestone and interbedded basaltic sills and dykes in Khyber Agency. In Salt Range rift related deposits are dominated by fluvial to glacio-fluvial sediments.
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