Large Benthic Foraminifera Biozonation of Mauddud Formation in Selected Section from Balad Oil Field, Central Iraq

Abstract

Three subsurface sections Ba-1, Ba-4, and Ba-8, and sixty-five thin sections were examined to investigate the biostratigraphy of the Mauddud Formation (age Early Albian - Late Cenomanian) within the Balad Oil Field located in central Iraq. The formation is lithologically composed of dolomitic limestone, creamy oolitic limestone, and shale. Orbitolina qatarica, Orbitolina sefini, and Orbitolina concava range zones were distinguished as biozones, including the Late Albian (Orbitolina qatarica), Late Albian to Early Cenomanian (Orbitolina sefini), and Early-Cenomanian (Orbitolina concava) zones. The age of these biozones confirmed the extent throughout the early Cenomanian age. Fossils of twenty-seven species of Foraminifera, including Conicorbitolina conica, Miliolids, Neoiraqia convexa, Nezzazata, orbitolina sp., Spiroluculina sp., and Trocholina sp., and others like Coral, gastropods, and rudest were identified.