STRATIGRAPHY OF THE LOW FOLDED ZONE | ||
| Iraqi Bulletin of Geology and Mining | ||
| Article 1, Volume 0, Issue 5, August 2017, Pages 63-132 | ||
| Abstract | ||
| The stratigraphy of the Low Folded Zone, in Iraq is reviewed. The oldest exposed rocks are Late Cretaceous in age, which belong to the Shiranish Formation, whereas the youngest are of Pliocene – Pleistocene age, which belong to the Bai Hassan Formation. The exposed stratigraphical column is represented by 24 formations. Moreover, ten main types of Quaternary sediments, which have wide geographic extent, are reviewed too. The Cretaceous and Paleogene rocks are mainly of marine carbonates with rare clastics, the Cretaceous rocks represent synrift sediments. The Early Neogene (Oligocene) rocks form a complex of reef – back reef – fore reef and are restricted almost in the eastern, central and western parts of the involved area, especially in Qara Chouq anticline, with other restricted exposures in different parts. The Early and Middle Miocene rocks are mainly of marine origin, lagoonal carbonates and evaporate, respectively. The Late Miocene rocks, which represent the beginning of the continental environment, together with the rocks of Pliocene – Pleistocene consist of molasse sediments, deposited in sinking foredeep. The Quaternary sediments are well developed, especially Pleistocene river terraces of different stages, and polygenetic sediments that fill the synclinal troughs, with other different types. For each exposed formation, the type locality, exposure areas, subsurface extension, main lithology (as described inform of members and/ or informal units), thickness, fossils, age, depositional environment, and the lower contact are described. The described lithologies of the formations by different authors from different localities are reviewed, with occasional remarks of the present authors. The main tectonic events and the paleogeography are reviewed briefly. Each formation is discussed, for majority of them the present authors' opinion are given, with many recommendations for future studies. Some new ideas dealing with many aspects for many formations including proposals for establishing new formations are given, too. | ||
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