Iraqi National Journal of Earth Science

Fundamentally, the current study is concerned with the investigation and diagnosing of Ostracoda fossils from the subsurface section of the Hartha Formation (Late Campanian - Early Maastrichtian) from (Ba-8) well at central Iraq. Fifty-nine Ostracoda species belonging to (29) genera/ subgenera from (13) families are diagnosed and classified to their ranks according to the standard systematic paleontology. Whereat (57) species are attributed to species previously described from local and regional studies. Two species are left under open zoological nomenclature basically because of lack of specimens. As a result, the study inferred that the species diagnosed in the Hartha Formation belong to the Late Campanian - Early Maastricht. As These species are very similar in terms of the external appearance and geologic age to the same species that were compared with them and which were previously described in the regions of East, West, and North Africa as well as the Arabian Gulf region.

Through a comprehensive taxonomic study of the ostracoda fossils in Fat'ha Formation in the stratigraphic section exposed within the eastern limb of Butmah anticline northwestern Mosul city, several genera and their belonging species of ostracoda have been identified from this previously unexamined section in terms of fossils. However, the focus in this research is on the genus Paijenborchellina and its species as it indicates an important environmental, age and geographical indications Six species belonging to this genus have been diagnosed as follows:
Paijenborchellina  keeni Gammudi & Keen, Paijenborchellina  libyca Szczechura,
Paijenborchellina cf. kausalis Khalaf, Paijenborchellina (Eupaijenborchella) iraqensisKhalaf, Paijenborchella (Eupaijenborchella) pronaLyubimova and Guha,andPaijenborchella (Eupaijenborchella) royi Khosla.
 

   A detail paleoenvironmental study of ostracods fauna to investigated the paleoenvironment of Khurmala Formation for two section Northern Iraq; the first (Hjran section) lies near Shaqlawa city, and the second (Dohuk section) lies near Dohuk city. Based on ostracods study conclude that Khurmala Formation were deposited in shelf environment, about (30 – 200) meter in depth.

Ostracoda assemblages have been studied from Fat'ha Formation (Middle Miocene) at SW limb of Bazian anticline, Sulaymaniyah,Kurdistan region, Iraq.  The Paleoecology of ostracoda assemblages points to shallow marine water that changes to barrier lagoon water setting due to tectonic activity event. The application of statistical analysis (Simpson index) leads to the subdivisions of Fat'ha Formation into five ecozones in the studied area.

Twenty two ostracoda species belonging to eight genera were described
from Avanah ,Sinjar, Khurmala, Aaliji, Akashat and Jaddala Formations, (Paleocene-Eocene) of North, West and Central Iraq of which four species are new, Abyssocypris zumarensis, sp.inov., Argilloecia heijranensis sp. nov., Argilloecia baajensis sp. nov., Schizocylhere anbarensis sp. nov. The identified species
shows strong affinities to those in India, North Africa and the Middle East (Southern New Tethys).

Forty three samples of limestone and shales from Tanuma Formation obtained from East Baghdad well (No. 11) at depths (2067 - 2177 m.) about 110 m. in thickness. Details investigated carried out identify twenty species of calcareous nannofossils, sixteen described from other region and four left open name because of rare and not clear samples. Furthermore, twenty four species of ostracodes belonging to fourteen genera were recorded, these are: Bairdia, Brachycythere, Curfsina, Cythereis, Cytherella, Cytherelloidea, Dolocytheridea, Ovocytheridea, Paracypris, Protocythere, Pterygocythere, Schuleridea, Spinoleberis, Veenia.
The recorded calcareous nannofossils assemblages permits to recognized two biozones these are:

2- Micula cf. decussata Interval Biozone (CC14).

1- Marthasterites furcatus Interval Biozone (CC13).
On the basis of biocorrelation with previous works Coniacian age confirmed for the Tanuma Formation at the studied section. The analysis of the ostracode fauna led to conclude that the palaeoecology of the Tanuma Formation in this section is shallow marine environment at depth about 200m in the neritic zone with warm water, under normal marine water salinity.