Keywords : Stratigraphy


Stratigraphy of the Dokan Formation (Upper Cretaceous) JebelAzmer- Sulaimaniya Area, Northeastern Iraq

Rund A. Hammoudi; Tarik S. Abawi

Iraqi National Journal of Earth Sciences, 2010, Volume 10, Issue 1, Pages 1-10

ABSTRACT Contrary to the present opinion regarding the Balambo Formation exposed in Jebel Azmer, Sulaimaniya area, northeastern Iraq, this study shows that the upper part (63 m) of the Balambo succession actually belongs to the Dokan Formation. The major hiatus between the lower part of the succession which represents the Balambo Formation and the upper part of the succession which we claim to represent the Dokan Formation together with the lithological differences give strong reason to characterize the studied section as the Dokan Formation. Dokan Formation in the studied section consists of light brown and white massive not well bedded limestone. Nineteen planktonic foraminiferal species have been identified from this section. The age of the Dokan Formation in the Jebel Azmer area is Middle - Late Cenomanian and is assigned to Rotalipora cushmani Zone; this indicates a major hiatus between the Dokan Formation and the older Balambo Formation of Middle-Late Albian age in this area.

Stratigraphy and Lithology of the Avroman Formation (Triassic), North East Iraq

Kamal H. Karim

Iraqi National Journal of Earth Sciences, 2007, Volume 7, Issue 1, Pages 1-12

Stratigraphy and lithology of the Avroman Formation (Triassic) were studied in Iraq and Iran. The study introduced new documentations about stratigraphy, lithology, fossil content and environment of deposition. Stratigraphically, it is very difficult to study the formation due to intense deformation, imbrication and even thrusting. However, it overlain by Qulqula Radiolarite Formation and Merga Red Beds in Iraq and Iran respectively while the underlying formation is not known as the lower boundary is not exposed. Lithologically, the formation consists mainly of pure limestone and no dolomite and marly limestone as previously mentioned. Microfacies include; grainstone, packstone and wackestone with association of oncoids, pelets, oolith and bioclasts. The fossils are relatively rare (except stromatolite or oncoids) and include gastropods, pelecypod green algae, echinoderms and forams. Environmentally, the formation was deposited in shallow isolated platform which was characterized by agitating warm normal marine water.