Source, tectonic setting, and facies distribution of the Silurian Sharawra Formation, the Old Qusaiba village, central Saudi Arabia

Abstract

Three outcrops of the Silurian Sharawra Formation at its type locality in Old Qusaiba Village in Central Saudi Arabia were studied for lithofacies distribution, petrographical, and geochemical characteristics. The outcrops were logged and nine different lithofacies were identified in the field. Petrographic analysis shows the Sharawra Formation to be mainly subarkosic associated with increasing mica content near to its contact with the underlying Qusaiba Shale Formation. Major and trace element geochemistry indicates that the sediments of the formation were deposited in a passive continental margin. The source area discriminating plots reveal acidic or felsic rocks such as granites as the probable provenance of the Sharawra sediments. The Chemical Index of Alteration (CIA) and Chemical Index of Weathering (CIW) indicate a moderate degree of weathering in the source area of these Silurian sediments. This study provides a baseline for future characterization studies of Paleozoic siliciclastic formations in Saudi Arabia and neighbouring countries.