Miocene Stratigraphy of Abu-Jir Fault Zone, Al-Baghdadi Sub-Basin, Western Iraq

Abstract

Stratigraphy of Late Oligocene to Middle Miocene age, suggested the carbonates evaporate succession in the area between Heet and Haditha cities within Abu-Jir fault zone has distinguished as "Al-Baghdadi sub-basin" after Al-Baghdadi city. It has NW–SE trending align the western bank of the Euphrates. Al-Baghdadi sub-basin is a local basin, which forms a part of the western marginal of the large foreland Tertiary basin( Zagros Basin) that was created on the Arabian shelf as a result of the collide of Arabian and Eurasian plates. The impact of the Abu-Jir fault on the formations on both regions of the Euphrates has been determined by observing the changes in thickness and lithofacies of the Euphrates, Jeribe and Fatˈha formations. On the western side, the Euphrates and Fatˈha formations were deposited with a relatively a little thickness, with absence of the Jeribe Formation between them and the top of the Euphrates Formation is above sea level. On the eastern side of the Euphrates River, the three formations were deposited with large thickness as compared to the western side, and the top of the Euphrates Formation is below sea level. This is enough to indicate that the western side was uplifting locally due to the activity of the Abu-Jir Fault as a positive flower structure during Miocene, while the eastern side was subsiding. Abu-Jir fault zone behaves as the basin bounding fault that acted like a growth fault. There are also variations in lithofacies between outcrops within Al-Baghdadi sub-basin as revealed from lateral missing or thinning of some layers.