Petrography and Diagenetic History of the Sarki Formation (Lower Jurassic) in Selected Sections from Kurdistan Region, Northeastern Iraq
Abstract
The petrography and diagenetic processes of the lower Jurassic Sarki Formation as one of the main Jurassic formations in Iraq, are studied in two selected sections in Warte and Zarwan, in the Imbricated Zone, Kurdistan Region, northeastern Iraq. The lithology of the Sarki Formation comprises dolomitic limestone and dolomite, thick-bedded brecciated dolomitic limestone, brecciated dolomite and very thin bedded marl. Mineralogical study using X-ray diffraction analysis has revealed that the main minerals include dolomite, calcite, quartz and illite. The petrographic investigation reveals the presence of few allochems mostly affected by different diagenetic processes especially dolomitization. The skeletal grains include ostracods, bivalves and echinoderms. Ooids, peloids and intraclasts are the main non-skeletal grains. The Sarki Formation has been subjected to different types of diagenesis processes, which are dolomitization, micritization, compaction (physical and chemical), cementation, dissolution, pyritization and fracturing. The diagenetic processes of the Sarki Formation relate to four diagenetic environments including marine, meteoric, burial and uplifting.
