Sedimentological Study of the Gulneri Formation (Late Cretaceous) at Azmir Anticline, Sulaymaniyah Governorate, Northeastern Iraq

Abstract

Gulneri Formation (Turonian) has been sedimentologically studied in one surface lithological section at Azmir Anticline, Sulaimaniya Governorate, Northeastern Iraq. Based on field data, the lower and upper boundaries with the Dokan and Kometan formations are unconformable, respectively. Petrographically, the particle portion of the Gulneri Formation consists mainly of planktonic foraminifera, particularly Planoheterohelix globulosa, Globigerinelloides ultramicus, Planoheterohelix moremani, Laeviheterohelix pulchra, and Dicarinella concavata, along with some benthonic foraminifera and bioclastics. The groundmass is predominantly composed of micrite. Generally, the sediments have undergone slight diagenetic processes, particularly compaction and cementation, with very minor dissolution. Microfacies analysis revealed that the Gulneri Formation succession consists of planktonic foraminiferal lime mudstone (G1), Globigerinelloides lime wackestone (G2), and bioclastic lime wackestone (G3). The Gulneri succession was deposited in a deep-shelf environment.