Microfacies and Sequence Stratigraphy of the Oligocene-Miocene Sequence at Golan Mountian, Kurdistan, Iraq

B. Al-Qayim¹, A. Ibrahim¹, and S. Othman¹

Abstract

The Oligocene – Lower Miocene carbonate sequence of northeast Iraq is potential reservoir rocks in many oil fields of the Foot-Hill Zone. A condensed section of this sequence is studied at the High Folded Zone from Golan mountain near Derbandikhan town, Kurdistan Region of northeast Iraq. The section is 27 meters thick and bounded by sequence boundaries of type 1 (top) type 2 (bottom). The underlying unit is the Pila Spi limestone Formation of Late Eocene, and the overlying unit is the Fatha Formation of Middle Miocene. Microfacies analysis and biostratigraphic and sequence stratigraphic investigations of this sequence reveal the occurrence of the following formations (From bottom to top): The Bajwan Formation (Rupelian ) with18 meters thick massive, fragmented to rubbly lagoonal limestone. Microfacies includes miliolid-bioclastic wackestone to packstone. Index forams includes: Archaias kirkukensis, Praerhapidionina delicate, Peneroplis thomasi. The Anah Formation (Chattian) is thin (3 m.) and characterized by grayish, rubbly to massive, lagoonal limestone horizon with foraminiferal-bioclastic packstone as the dominating microfacies. Index forams includes: Meandropsina anahensis, Rotalia vienoti and Miliolidae. The uppermost six meters represents a cyclic alternation of limestone (calcarenite) and sandy dolomitic limestone. Three complete cycles were recognized, the lower two represent the Aquitanian Euphrates Formation, and the upper cycle seems to represent the Burdigalian Jeribe Formations. Common microfacies includes oolitic grainstone, pelloidal-bioclastic packstone, and arenaceous bioclastic dolostone. Recognized bioclasts includes abundant mollusk, forams and algae.

AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain