Facies Analysis and Paleoenvironments of the Lower Jurassic Silisiclastic-Carbonate Succession, Western Iraq

Abstract

The Lower Jurassic Silisiclastic-Carbonate Succession of Western Iraq consist(from bottom to up) of Ubaid, Hussiniyat, and Amij succession. They were deposited within a variety of continental, transitional and marine environments. Microfacies analysis of the Ubaid Formation reflect deposition in different environments within the carbonate platform. Lithofacies analysis of the clastic unit of the Hussiniyat Formation reflect deposition within a meandering river system, the Coastal plain facies can also be recognized within the lower part of the upper carbonate unit. The Amij succession consist of a lower clastic unit with few carbonate interbeds and an upper carbonate unit. This succession consist of a wide range of lithofacies reflecting the different subenvironments of fluvial, transitional and shallow marine environments. The activity of the Rutba uplift and Anah Graben during the Early Jurassic greatly affected the paleogeography of the basin in the study area.