This study deals with the biostratigraphy of Shiranish Formation (Late Cretaceous), depending on the Ammonite and associated Foraminifera in four outcrop sections, three of which are located in Al-Sulaimaniya governorate  (Dokan, Esewa and Kanny dirka sections) and one in Erbil  governorate, northern Iraq (Hijran section). Fourteen species of Ammonite belonging to fourteen genera were determined, which are: Dsemoceratidae, Gaudryceras, Gunnarites, Hoplitoplacenticeras, Kitchinites, Kossmaticeratinae, Neancyloceras, Neokossmaticeras, Nostoceras, Paratexanites, Partschiceras, Phylloceras, Pseudophyllites and Yubariceras. Also, thirty- five species of Foraminifera belonging to thirteen genera w

The Aqra - Bekhme, Shiranish, Tanjero and Kolosh formations outcrop in the High Folded Zone, Northern Iraq in Erbil and Sulaymaniyah governorates. The formations have been studied at two selected geological sections (Bekhme Gorge and Zarda Bee). In this study, these formations are investigated based on both benthic and planktonic foraminifera. Depending on foraminifer’s investigation, three biozones have been recognized; two biozones are identified in the benthic foraminifera and the third one is identified in the planktonic foraminifera as follow:

1. Siderolites calcitropodes - Orbitoides apiculatus - Omphalocyclus macroporus Assemblage zone.
2. Loftusia morgani range zone.
3. Aba

This study involves microfacies analysis of the Kometan Formation from northeastern Iraq supported by detailed petrographic investigation for the main components and diagenetic processes using a petrographic microscope, scanning electron microscope (SEM), and X-Ray diffraction (XRD). The techniques have revealed that the formation includes two microfacies; lime wackestone and lime packstone microfacies which in turn are subdivided into seven sub-microfacies, that were deposited in the quiet and deep marine environment. Planktonic foraminifera (keeled and globular chamber types) are dominant, along with oligostegina in addition to subordinate benthonic foraminifera and fine-grained bioclasts. Calcite forms the main mineralogical compositi

The middle Cenomanian – early Turonian Mishrif Formation, a major carbonate reservoir unit in southern Iraq, was studied using cuttings and core samples and wireline logs (gamma‐ray, density and sonic) from 66 wells at 15 oilfields. Depositional facies ranging from deep marine to tidal flat were recorded. Microfacies interpretations together with wireline log interpretations show that the formation is composed of transgressive and regressive hemicycles. The regressive hemicycles are interpreted to indicate the progradation of rudist lithosomes (highstand systems tract deposits) towards distal basinal locations such as the Kumait, Luhais and Abu Amood oilfield areas. Transgressive hemicycles (transgressive systems tract deposits)

The study of Shiranish Formation rocks in southern part of Iraq at Ansab area well (KH-6)
were carried out. The formation is tongued with tayarat formation, which bounded from top
and bottom, the upper tongue at thickness 49m. and tongued at depth (476-525m.) the lower
tongue at thickness 4m. tongued at (541-537m.).
The rocks of this formation were divided into three sedimentary microfacies:
1- Dolomitized formininferal Wackestone facies.
2- Dolomitized formininferal Mudstone facies.
3- Dolostone facies.
34 slides were investigated depending on mineralogical, compositional and biological
processes and compared diagenesis which reflect open marine shelf at lower part of formation
(F.Z.2) (S.M.F.8), but at the

   Calcareous nannofossils were documented from the upper part of the Cretaceous Balambo Formation in northern Iraq with the aim of determining an evidence for the Oceanic Anoxic Event. A detailed investigation of the calcareous nannofossils led to the identification of twenty-four species. Regarding these data, Discolithus litterarius (Górka, 1957) was identified at the studied interval with the age of Early Aptian.

   Early Aptian assemblages are dominated by nannoconids that drop sharply within the D. litterarius nannofossil zone, which may be related to the nannoconid crisis recorded in the Early Aptian in the other parts of the world. This event is coincided by a decrease in CaCO_3<

A surface section of the Gercus Formation (Middle-Late Eocene) was studied in Berafat area, Dohuk Governorate, Northern Iraq. The Gercus Formation consists of a mixed siliciclastic sediments, evaporates and carbonate sequences in the studied region, predominantly in the upper and middle parts. Nevertheless, it usually consists of upward-fining carbonate-rich sandstone cyclothems, marl, conglomerate and siltstone along with a gypsum lens and thin micrite carbonate beds.  The Gercus Formation was deposited in delta and delta front of occasionally depositional environment which is represented by red-brown claystone and reddish-brown mudstone lithofacies. Cross bedded  pebbly sandstone, trough cross-bedded sandstone  and lamin

This study deals with establishing the depositional environment of the Fatha Formation through facies analysis. It also deals with dividing the formation into units based on the rhythmic nature. Data from selected shallow wells near Hit area and deep wells at East Baghdad Oil field are used. Five major lithofacies are recognized in this study, namely, greenish grey marl, limestone, gypsum (and/or anhydrite), halite and reddish brown mudstone (with occasional sandstone).The limestone lithofacies is divided into three microfacies: Gastropods bioclastic wackestone microfacies, Gastropods peloidal bioclastic packstone, and Foraminiferal packstone microfacies.The lithofacies of the Fatha are nested in a rhythmic pattern or what is known as sh

Basin analysis (geohistory) is carried out on the Cretaceous to Tertiary succession in five wells at Kirkuk and Bai Hassan Oil Fields during the Aptian to the Recent. The Foothill Zone exhibited a complex subsidence and uplift history over a period of about 132 Ma. The results from studied wells backstripping provide a record of the subsidence and uplift history in a number of important Meso-Cenozoic depositional successions. They show that there are three distinct episodes separated by unconformity surfaces. The value of compaction varies from large during the Cretaceous period to less clearly during the Paleogene and then almost non-existent during the Neogene. Generally, the subsidence is continuous and gradual during Mesozoic and sud