Journal of Earth Sciences and Geotechnical Engineering

The Miocene Sequence in Iraq, a Review and Discussion, with emphasize on the Stratigraphy, Paleogeography and Economic Potential

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• Abstract

   

  The Miocene Sequence (23.03 – 5.33 Ma), in Iraq has large diversity in lithofacies, biofacies, depositional environments, tectonic effect, and geographical distribution. The Savian movements caused development of broad and shallow basins, which had covered large areas in the Iraqi territory, as compared with the earlier Oligocene sequence, which was characterized by great sea level drop causing very limited depositional basins, the main intraplate basin became narrower due to the tilting of west Arabia. The Miocene Sequence, in Iraq includes 11 stratigraphic units, some of them have not formation order, and these are: Serikagni, Euphrates, Ghar, Dhiban Anhydrite, Jeribe, Fatha, Nfayil, Injana, Mukdadiya, Govanda Limestone and Red Bed Series. However, some of these units have age that is not limited to the Miocene, they have range of either younger or older than Miocene. The main major event that had occurred during the Miocene was the change from the dominating marine phase in the Early Miocene to continental phase during the Late Miocene. This main change is attributed to the major thrusting, which occurred during the collision of the Sanandaj – Sirjan Zone with the Arabian Plate. This event also is considered as the beginning of the Neotectonic effect in Iraq. Many formations were terminated; others were started with different lithological and depositional environments, as well as different faunal assemblages. The faunal assemblages, depositional environments, paleogeography, lithology of each exposed stratigraphic units are reviewed and discussed. Moreover, the tectonic effect on each exposed unit in different tectonic zones is discussed too, beside the mutual relation between the exposed units.