Biostratigraphic Analysis of the Oligocene-Early Miocene Successions From Sulaimani Area, Kurdistan Region, Iraq

Abstract

Three sections (Darzila, Hazar Kani and Basara) of the Oligocene –Early Miocene successions from Sulaimani area, Kurdistan region-NE Iraq, were measured and studied in order to interpret the biostratigraphic zonations at the Low and High Folded Thrust zones boundary, Low Folded Thrust zone, which are integrated with strontium stratigraphic dating. Accordingly, five biozones have been identified and they are:1- Nummulites vascus- Nummulites intermedius- Nummulites fichteli Assemblage Zone (Shallow Benthic Zone, SBZ 22A) represents the Rupelian age, 2- Lepidocyclina dilatata- Nummulites vascus - Nummulites fichteli Assemblage Zone (SBZ 22B-Early Chattian), 3- Praerhapydionina delicata- Archaias kirkukensis Assemblage Zone (SBZ23) representing the Late Chattian age, 4- Austrotrillina howchini- Peneroplis evolutus Assemblage Zone (SBZ24), almost point to the Aquitanian age and finally 5- Austrotrillina asmariensis- Dendritina rangi Assemblage Zone (equivalent to SBZ25) representing the Burdigalian age. Based on the distribution of the larger foraminifera and strontium stratigraphic dating, the Baba Formation is of Early to Late Oligocene age (Rupelian- Early Chattian), while the Bajawan Formation is of Chattian age, in addition to that, the Anah Formation is of Early Miocene age (Aquitanian) and the Jeribe Formation is of Burdigalian age. It is worthy to mention that the Oligocene-Miocene boundary has been identified in the studied area as well as, the gap duration between different formations of the Kirkuk Group, and the gap durations due to the absences of Serikagni, Euphrates and Dhiban formations.

Biostratigraphy of the Early Turonian- Late Campanian pelagic limestone (Kometan and Gulneri formations) near Sayid Sadyq Town, Kurdistan Region, NE-Iraq.

“…The age of this zone indicates Early Turonian, which is equivalent to that of Abdel-Kareem et al (1996) [29], [17], and the older part of Globotruncana helvetica zone of Youkhanna (1976) [9], Postuma (1971) [16]. this zone is also equivalent to that proposed by Lawa and Al-Khafaf (2022) [6], Hussain and Al-Sheikly (2015) [30], and Al-Khafaf (2014) [31], also this zone corresponds to the older part of Marginotruncana helvetica zone of Ghafor et al (2004) [32], Ghafor (1993) [33].…”

“…Youkhanna (1976) [9] indicated Turonian-Santonian age and divided it into 3 biozones. Al-Dhaif (1997) [10] in the Jambour field, Abawi and Hammoudi (1997) [3] in the Kirkuk area, North Iraq, and Al-Khafaf (2005) [11] in the Dokan-Endezah areas studied the foraminiferal biostratigraphy of Kometan Formation and indicates Late Turonian-Early Campanian age., Lawa and Al-Khalaf (2022) [6] studied the Dokan, Guneri and lower part of Kometan Formation in Kosrat anticline, and indicated unconformity at the base and top of the Gulneri Formation with both Dokan and Gulneri Formations. In contrast to the unconformable boundary of the Gulneri and Kometan formations, Karim, and Taha (2009 b) [12] proved the conformable boundaries of the Gulneri Formation and the absence of unconformity.…”

“…The foraminiferal biostratigraphy of the Gulneri Formation was studied by Abawi and Hammodi (1997) [3] in the Kirkuk area and inferred Late Turonian, while Abawi and Mahmood (2005) [4] and assigned its age to Middle-Late Turonian age in the Jambour well. The biostratigraphy of the Gulneri Formation was also studied by Abawi et al (2006) [5] in the type section, Dokan area., Lawa and Al-khafaf (2022) [6] studied its biostratigraphy on the Kosrat anticline and indicated that the Formation consisted of black, bituminous, finely laminated, pink color calcareous shale, and they assigned it to the Early Turonian age. Karim and Taha (2009a) [7] proved that the Guneri Formation was deposited in the deep basin and deposited during the drawing of the Arabian platform (Qamchuqa Formation) and the same idea was repeated by Lawa and Al-Khafaf (2022) [6].…”

“…The biostratigraphy of the Gulneri Formation was also studied by Abawi et al (2006) [5] in the type section, Dokan area., Lawa and Al-khafaf (2022) [6] studied its biostratigraphy on the Kosrat anticline and indicated that the Formation consisted of black, bituminous, finely laminated, pink color calcareous shale, and they assigned it to the Early Turonian age. Karim and Taha (2009a) [7] proved that the Guneri Formation was deposited in the deep basin and deposited during the drawing of the Arabian platform (Qamchuqa Formation) and the same idea was repeated by Lawa and Al-Khafaf (2022) [6]. Jassim and Goff (2006) [13] at the top and a simple geological map (Satellite image of the Google Earth Image) of the area around the sampled section.…”

Diagenesis processes of the Gulneri Shale, Kometan, Mushorah formations within the upper Turonian - lower Campanian Supersequence from Bai Hassan area, North of Iraq

“…studied the biostratigraphy of planktic foraminifera fossils of period the lower Turonian-lower Maastrichtian and determined the age of the Gulneri Shale Formation of lower Turonian-upper Turonian, and the Kometan Formation of lower Turonian-lower Campanian, and Mushorah Formation from the lower Santonian-lower Campanian, while [4] studied the biostratigraphy of the Gulneri Shale Formation and the lower part of the Kometan Formation in the Kosrat fold in northeastern Iraq, and showed that the Gulneri Shale Formation consists of the black shale and a thickness of about 1.5 m, which reflects the events of OAE _ 2, and that the lower and upper contact surfaces of the formation are unconformity with the Dokan Formation underline it and the Kometan Formation above it and determined its age with lower Turonian, [5] by studying the paleoenvironment of the Kometan Formation in the Dokan area, concluded that the formation was deposited in a deep marine environment depending on the masses of Ostracoda and some types of foramnifra. , The study area included two subsurface sections within the Dome of Daoud in the Bai Hassan field in northern Iraq, consisting of two wells (BH-16 and BH-86) as shown in Table (1) [6] and located within the Low Folded Zone within the Western Zagros Fold -Thrust Belt according to the tectonic divisions of Iraq [7] Fig ( 1).…”