Sedimentology and Stratigraphic Evolution of the Warchha Sandstone: Fluvial cyclicity and Sequence stratigraphy of the Early Permian Warchha Sandstone, Salt Range, Pakistan

During Early Permian (Artinskian) times, fluvial conditions prevailed in the Salt Range, Pakistan. Deposits of the Warchha Sandstone are characterised by a range of fluvial facies and architectural elements that together preserve a record of both the proximal and distal parts of a meandering river system. The Warchha Sandstone records the progradation of a wedge of non-marine strata into an otherwise shallow marine realm. The underlying marine Dandot Formation is terminated by a major unconformity that represents a type-I sequence boundary associated with a region-wide relative sea level fall and a significant regression of the Tethyan shoreline. The overlying Warchha Sandstone represents the onset of the subsequent lowstand system tract in which – according to palaeocurrent and clast provenance analysis – northward-flowing meandering river systems were supplied with clastic detritus from a tectonically-active source area that lay to the south (the Aravalli and Malani ranges). This episode of fluvial sedimentation was terminated by a widespread marine transgression, as represented by the abrupt upward transition to the overlying shallow marine Sardhai Formation.