The Early Cambrian Khewra Sandstone, Salt Range, Pakistan: endorsing southern Indian provenance

The Early Cambrian continental Khewra Sandstone, Salt Range, Pakistan consists of lithics, feldspar and quartz in order of increasing abundance. Both mono- and polycrystalline quartz are observed. The feldspar is predominantly plagioclase and potassium feldspar; lithics represented are of sedimentary, metamorphic and igneous origin. Accessory minerals present include micas (muscovite and biotite), opaque mineral grains, zircon, rutile, epidote, glauconite, chlorite and monazite. Ferruginous clays are present as matrix and the major cements are calcareous, siliceous and ferrous. The sandstone is grain supported, moderate to well sorted and rounded to well rounded with medium to high sphericity. Overall, the sandstone is texturally and mineralogically mature and is classified as sub-arkose and quartz arenite. Provenance from cratonic interior and recycled orogeny and the paleoflow indicate source from southeast. Petrographic analysis and field characteristics of the sandstone indicate that the source areas were characterized by uplift of high relief continental block. The rocks weathered from the source areas primarily included granites, together with metamorphic basement and sedimentary rocks. Regional palaeogeographic reconstructions indicate that the Khewra Sandstone detritus was derived from the Indian Craton to the south and southeast. The southeastern source area of the Khewra Sandstone attests to the Pan-African orogeny (similar to 500 +/- 25 Ma) and contemporaneous large-scale diastrophism, which resulted in Gondwanic India upheaval, providing source for the Cambrian Khewra Sandstone of the Salt Range, Pakistan.