Najah Alwan Owaiz
Prof. Dr. Mazin Y. Tamar-Agha
Department of Geology – University of Baghdad – Collage of Science
This study deals with the petrography of the Mulussa Formation (Carnian - Norian age) in western desert of Iraq (NE of Rutba city ).
About (80) thin sections taken from carbonate sediments samples of four outcrop sections are carried out to recognize the constituents (skeletal , non-skeletal grains and cement) of the lithological units. Skeletal grains are represented by Pelecypods (Bivalve), Gastropods, Crinoids, Echinoids, Alge, Foraminifera and fragments of organisms shells. All of these skeletal grains were entirely affected by diagenetic processes. Non-skeletal grains include carbonate grains: pellets and ooids while non-carbonate grains: quartz. Regarding cement, it is mostly represented as crystals of dolomite ( Aphanocrystalline to medium crystalline ) with euhedral to subhedral edges.Diagenetic processes is represented by dolomitization, dedolomitization, dissolution, cementation and silica replacement with dolomite. All this petrographic description is done by using a polarizing microscope.