Keywords : Lower Cretaceous

Paleoecology of Garagu Formation and the Upper Part of Ratawi Formation (Lower Cretaceous) of Central Iraq

Jinan M. Al-Basher; Sanad A. Al-Khashab; Salih K. Khalaf

Iraqi National Journal of Earth Sciences, 2011, Volume 11, Issue 1, Pages 1-14

Ostracode assemblages from Garagu and Ratawi Formations (Lower Cretaceous) from Makhul-2 (Mk-2) and East Baghdad-1 (EB-1) boreholes were studied in details, leading to the conclusion that Garagu Formation deposited under shallow marine sublittoral environment with normal salinity and warm water, while Ratawi Formation deposited in shallow marine environment with anoxic environments.

Tectonostratigraphy of Lower Cretaceous in Southern Iraq

Kaise M. Al-Bayatee Wathiq GH. AL-mutury Rafed A. AL-Muhammad

Iraqi National Journal of Earth Sciences, 2010, Volume 10, Issue 2, Pages 29-44

Stratigraphic units during Lower Cretaceous in southern of Iraq
were affected largely by tectonic agent. Neo-Tethys ocean
occupied the distance between passive margins of Arabian and
Iranian plates. South of Iraq represented the continental shelf of
passive margin of Arabian plate. This tectonic situation made the
sediments in eastern parts of passive margin in south of Iraq
effected by marine agents, and the sediments in western parts was
effected by continental agents, whereas the middle parts was
effected by both agents. As result of that, three sediment regions
were formed in south of Iraq. First, marine sediment region that
occupy the eastern part of south of Iraq near the Iraq-Iran borders.
Second, mixed sediment region that occupy Basra area and extend
toward north. Third, continental sediment region that occupy
western part of Basra near the western desert. Half graben basins
that formed by listric faults in the passive margin caused the local
changes in distribution of sediments in south of Basra. These three
sediment regions formed all during Lower Cretaceous and maybe
extend toward the middle of Iraq and north of Baghdad

Biostratigraphy of the Balambo Formation (Lower Cretaceous ) in Jebel Azmer – Sulaimaniya Area, Northeastern Iraq

Rund A. Hammoudi; Tarik S. Abawi

Iraqi National Journal of Earth Sciences, 2008, Volume 8, Issue 1, Pages 24-33

The Balambo Formation (Lower Cretaceous), exposed on Jebel Azmer in Sulaimaniya area northeastern Iraq, consists mainly of well bedded hard limestone. Outcrop of 224 m of the upper part of the Balambo Formation are well exposed on the surface with a steeply dipping angle. Planktonic foraminifera represent the major microfossil assemblage of the Balambo Formation. Nineteen cosmopolitan planktonic foraminiferal species were recorded from 92 samples. The identified planktonic foraminifera are of typical Tethyan character. Biostratigraphically the exposed part of the Balambo Formation is defined by four zones and two subzones, these are in ascending chronological order: Ticinella primula Zone, Biticinella breggiensis Zone which is divided into two subzones (Ticinella praeticinensis and Rotalipora subticinensis Subzones), Rotalipora ticinensis Zone and Rotalipora appenninica Zone. Accordingly the age of the Balambo Formation in Jebel Azmer is Middle–Late Albian. The presence of a major hiatus at the end of the Rotalipora appenninica Zone delineates the upper boundary of the formation in the studied section.