Biostratigraphy of the Late Cretaceous-Early Paleocene Succession in Selected Wells, Jambur Oil field, Kirkuk, Northern Iraq

Abstract

The Late Cretaceous-Early Paleocene Shiranish and Aliji formations have been studied in three selected wells in Jambur Oil Field (Ja-50, Ja-53, and Ja-67) in Kirkuk, Northeastern Iraq. This study included lithostratigraphy and biostratigraphy. The Late Campanian-Maastrichtian Shiranish Formation consist mainly of thin marly and chalky limestone beds overlain by thin marl beds, with some beds of marly limestone representing an outer shelf basinal environment, the unconformable contact with the above Middle Paleocene-Early Eocene Aliji Formation contain layers of limestone with marly limestone and chalky limestone which represents an outer shelf basinal environment. Five Biozones in the Shiranish Formation were determined which are: 1.Globotruncanita calcarata Range Zone (part). 2.Globotruncanella havanensis Partial Range Zone. 3.Globotruncana aegyptiaca Interval Zone. 4.Gansserina gansseri Interval Zone (Part). 5.Abathomphalus mayaroensis Range Zone. While in Aliji Formation there were two biozones determined which are: 1.Guembelitria Cretacea Partial-Range Zone. 2.Parvularugoglobigerina eugubina Total-Range Zone.