SEDIMENTARY FACIES AND ENVIRONMENTS OF SHARI PLAYA, CENTRAL IRAQ

Abstract

Shari Playa, which is the only source of natural sodium sulphate in Iraq, is a longitudinal closed basin located about 150 Km to the north of Baghdad, Central Iraq. The playa receives its sediments from major ephemeral streams originated from Himreen Mountain, which surrounds the playa from the northeast and east, forming a seasonal lake. Most streams passes through sand dunes located between Himreen Mountain and the playa. The sediments brought by these ephemeral streams developed seven sedimentary facies, which are vertically and laterally interrelated, deposited in five sedimentary sub-environments over the underlying Clastic Substrata Facies. These include the salt bearing facies group (salt crust, black mud, glauberite-rich mud and gypsum-rich mud), Sand – Silt Facies, Coarse Sand Facies and Windblown Sand Facies. Their thickness are generally wedging out towards the periphery. The sediments distribution and geometry indicate that the playa is a subsiding N – S oriented graben.