Subenvironments of Jeribe Formation (M. Miocene) deduced from microfacies study, Zurbatiya Area, South-East of Iraq

Abstract

The current study of Jeribe Formation (Middle Miocene) at Zurbatiya area, South-East of Iraq. It is, structurally, located in the Low Folded Zone. The topic depends mainly on the study of microfacies under a microscope. One surface section in the Zurbatiya area is represented in the Wadi Al-Numur section. It is composed basically of dolomitic limestone. Petrography provides a diversity of fauna, such as benthic foraminifera Miliolid, Borelis melo curdica, and Rotalia in addition to Ostracoda, Algae, Coral, and Mollusks. Borelis melo curdica is considered an index fossil for the Jeribe Formation. The non-skeletal grains like peloids, ooids intraclasts, and extraclasts. The Jeribe Formation was affected by many diagenetic processes like neomorphisim, dissolution, cementation, dolomitization, compaction, and silicification. Sedimentary microfacies are classified into three main microfacies, which are dolomudstone, dolowackestone, and dolopackstone. These microfacies were divided into many submicrofacies, which are peloidal dolomudstone, ostrocods dolomudstone, rotaliids dolowackstone, miliolid dolowackstone, bioclasts dolowackstone, green and red algae dolowackstone, red algae dolopackestone, and coral dolopackestone. The evidence from petrography and microfacies analysis supports that the Jeribe Formation was deposited in the back reef, reef, and lagoon environments.