Study of Planktonic foraminifera within Shiranish formation in selected wells from middle and southern Iraq

الملخص EN

Background: In this study, some taxa of planktonic foraminifera fossils were relied upon, to determine the biozones of the diagnosed genus and the ages based on those species and to compare those areas with the areas identified in previous studies to find out the differences between the northern and southern areas in Iraq.

Twenty three species of planktonic foraminifera were identified, which belong to eight genus belonging to the families (Globotruncanidae and Heterohelecidae) within five wells distributed over the study area that included (R-698, Ru-479, Ga-198P, EB 103, EB 104).

The study showed that there are three biozones: Gansserina gansseri zone, Globotruncana aegyptiaca zone, Globotruncanita stuartiformis zone.

Materials and Methods: After collecting the samples and bringing them to the laboratory, each sample was treated separately, where the model was cooked at a high temperature for two hours after adding the dispersant substance (NaOH) to it, and then the samples was washed with a sieve with a size of 63 microns and left to dry, then the samples was sieved 450 micron to separate the sediments from the fossils, and then the process of picking up the foraminifera genus and isolating those fossils in special folders to make the diagnosis process under a reflecting microscope inside the Department of Earth Sciences / College of Science / University of Basrah.

Results: Depending on the diagnosis of these groups of planktonic foraminifera were divided into several areas.

Conclusion: Depending on the results obtained from the current study, It was found that the age of the Shiranish formation in the wells studied extends from the upper part of the Late Campanian - Middle Maastrichtian.