Diagenetic processes of Shiranish Formation in Bekhair Anticline, Dohuk Governorate, Northern Iraq

Abstract

A detailed petrographic study is achieved of more than 120 thin sections of the carbonate rocks samples for Shiranish Formation (Early-Late Maastrichtian) from three outcrops (Brie Bahar, Ikmalah, and Zoe) at Bekhair anticline, Dohuk city, northern Iraq to identify the impact of the diagenesis processes. The diagenesis process varies in intensity from one microfacies to another at the Shiranish Formation successions, the most important dominant diagenesis processes that are identified in the current study and according to its probable timing sequence are bioturbation, compaction, cementation, dissolution (porosity), micritization, neomorphic (recrystallization), authigenic minerals (pyrite and Glugonite), fractures, and formation of veins.Among all the observed diagenetic features, dissolution and recrystallization contributed to porosity and permeability enhancement. The cementation, compaction, and micritization have a negative impact on porosity and permeability. All diagenetic indications referred that the environment that has affected the carbonate rocks in the Bekhair anticline was the stagnate Burial Diagenetic environment, as well as the Marine Phreatic Environment, and Fresh groundwater phreatic environment.