Petrography, detrital zircon provenance and depositional environment of the Early Cretaceous Lumshiwal Formation, Hazara Basin, Lesser Himalayas, Pakistan

Detailed petrographic and geochemical study was carried out to unravel the provenance, tectonic setting, environment of deposition, and diagenetic processes of the least investigated Early Cretaceous Lumshiwal Formation in Hazara Basin, Lesser Himalayas, Pakistan. The Lumshiwal Formation in Eastern Hazara Basin exclusively constitutes sandstone. Petrographic modal analyses of sandstone showed that monocrystalline quartz is 82% and polycrystalline quartz is 3%. The abundance of non-undulose to weakly undulose monocrystalline quartz points to derivation from the igneous source rock. The feldspars dominant in this sandstone are albite (plagioclase) and microcline. Furthermore, the detrital heavy minerals identified are muscovite, zircon, epidote, rutile, apatite, tourmaline, monazite, and titanite which also point to acidic plutonic rocks. Based on a high abundance of quartz, the sandstone is classified as quartz arenite based on the QFL diagram, suggesting that the sandstone is mineralogically mature. In the analyzed sandstone samples, the dominant cementing materials are silica as quartz overgrowth, calcite, and hematite. Silica as an overgrowth in pore spaces as cement precipitation, sutured and long boundaries, tangential and concavo-convex contacts of quartz grains, and albitization of feldspar grains as a result of alteration are the prominent diagenetic modifications in the analyzed sandstone. Modifications such as quartz overgrowth, amelioration of intragranular fractures of quartz and feldspar with ore mineral, and stylolitic boundaries of the grains, which are a result of deep burial resulted from increased pressure and geothermal gradient, represent the late phase of diagenesis. Detrital Zircon U-Pb-Hf analysis gives an age population spanning around ⁓ 480–1100 Ma. Hf isotopic analyses show negative εHf(t) values ranging between − 0.07 and − 23.5 suggesting that the detrital zircon grains are of Mesoproterozoic-Archean. The QtFL modal composition and the detrital zircon U-Pb-Hf analysis points Craton Interior setting at source indicating a similar Indian plate provenance. Fossil record such as Ammonites Sp also indicates the deposition of the Lumshiwal Formation during the Early Cretaceous. Lithofacies combined with petrographic analysis suggest deposition of Early Cretaceous Lumshiwal sandstone in shallow marine deltaic environment along the northwestern passive margin of the Indian plate.