The Warsak basic rocks: Initial-rift stage continental tholeiites of Permo-Triassic "Panjal" affinity
Abstract
A suite of basic rocks, comprising microgabbros, dolerites, metabasalts and volcaniclastic sediments, occurs associated, both in space and time, with the alkaline granites at Warsak near Peshawar. Detailed geochemistry, mainly based on trace elements, suggests that the magmatism responsible for the Warsak basic rocks was tholeiitic in composition and was erupted/intruded in a within-plate continental setting. Furthermore, the Warsak basic rocks have geochemical composition closer to rift volcanics rather than the plateau basalts.
The Warsak rocks, in this study, have been identified to be related with the suite of tholeiitic basalts commonly encountered as dykes and sills in the Lower Palaeozoic or older rocks of northern part of the Indian plate. The volcanic and volcaniclastic comPonent in the Warsak area is directly correlatable with the Karapa greenschist in Ambela area, and the amphibolite marker horizon in the upper part of the Marghazar Formation of Lower Swat which are in turn cot-relatable with the Permo-Triassic Panjal volcanics of Kaghan and Kashmir.
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