Keywords : Southern Iraq

Systematic Study of Some Recent Pelecypods From Hajam Island in Khor Al- Zubair, Southern Iraq

Ali H. Elewi; Ramzi K. Al-Naser; Mohammed W. Al-Abbasi

Iraqi National Journal of Earth Sciences, 2008, Volume 8, Issue 2, Pages 47-59

Khor Al-Zubair is a shallow arm, semi restricted channel, located at the northwestern part of the Arabian Gulf. The study area ( Hajam island ) is situated at the southern part of the channel, comprised sandy, silty and muddy sediments.Systematic description is made for the studied pelecypod shells assemblage, which are collected from the Hajam island in Khore Al-Zubair. These assemblage include nine species belonging to seven genera and six families. These species are; Barbatia helblingii, Pinctada margaritifera, Pinctada radiate, Spondylus (Spondylus) gaederopus, Diplodonta (Diplodonta) rotundata, Semele sinensis, Circe (Circe) scripta, Circe (Circe) intermedia and Bassina (Bassina) calophylla.

Mineralogy and Geochemistry of Yamama Formation (Late Beirriasian-Early Valanginian), Southern Iraq

Abdul-Mutalib H. Al-Marsoumi Rafed A. H. Al-Mohamed Haitham G.F. Hmood

Iraqi National Journal of Earth Sciences, 2003, Volume 3, Issue 1, Pages 11-29

A total of 138 core samples were collected from six subsurface sections of Yamama Formation. These sections were randomly distributed in West Qurna and Nasiriya oil fields. The collected samples were analyzed for; Ca, Mg, Fe, Na, Mn, Sr, Pb and insoluble residue using wet chemical analyses, in addition of representative samples were examined by X-ray.
X-ray diffractograms revealed that the bulk samples consist of calcite, dolomite, and subordinate detrital quartz. Whereas, the clay fractions of insoluble residue consist of kaolinite, illite, illite- montmorillonite mixed-layer.The kaolinite percentage shows a marked increase in Nasiriya field (i.e. towards the paleoshorline).
The concentration of Mg and Na progressively increases as water salinity increases. The Fe and Mn concentrations are function of the clay content of the sediments, while the concentration of Sr is largely controlled by the fossil debries. Regarding Pb no systematic trend in its distribution was noted,i.e. it has an eratic distribution.
Ca/Mg molar ratio showed a less effective dolomitization process while Sr/Ca and Fe/Mn atomic ratios proved that Yamama Formation were deposited in a shallow marine-lagoonal-brackish environment.