Tectonostratigraphic Evolution of the Western Desert of Iraq

Abstract

The study area is in the northern part of the Western Desert of Iraq. From the conclusion of Paleozoic and Mesozoic basins and their distribution according to the available geological (outcrops and boreholes) and geophysical data (seismic, gravity and magnetic interpretations controlled by geological data), it is found that, Triassic- Jurassic (and sometimes Cretaceous) basins are found closely related to the basic or ultrabasic basement (for example Anah, Tilul, and Ras Al-Fahama basins). These basins were formed by isostatic adjustment during the extension phase that took place in the Early Mesozoic (may be Triassic or Jurassic) which caused subsidence of heavy parts (basic or ultrabasic) of the basement. From the style and thickness of sediments it is clear that the northern and eastern parts of the area exhibit evidence of a tendency for uplift during Paleozoic times (forming ridges or horsts) and down-warping during the Mesozoic times (forming basins or grabens). While in contrast the western part of the area exhibits evidence or tendency for down-warping during Paleozoic forming basin or graben (as in Gaara basin) and uplift during the Mesozoic times.