Stratigraphic and Microfacies Study of Kometan Formation (Upper Turonian-Lower Campanian), in the Dokan area, Northern Iraq

Zaid A Malak

doi:10.46717/igj.54.1f.6ms-2021-06-26

Abstract

The Kometan Formation is widely distributed in the northern (Kurdistan region) and central Iraq. The studied area is located near the Dokan Dam, about 58 km., to the Northwest of the Sulaymaniyah city, Northeastern Iraq. The Kometan Formation is exposed on the southwest flank of the Sarah anticline. The formation consists of limestone and dolomitic limestone, which have cherts nodules throughout the formation. The Gulneri Formation is recorded below the Kometan Formation with unconformable contact, while at the top is bounded by the Shiranish Formation unconformably too. Three microfacies are identified, these are lime mudstone, planktic foraminiferal lime wackestone-packstone, keeld planktonic foraminiferal lime wackestone-packstone microfacies. All the sedimentary and fossil evidence refer that the sedimentary environment of the formation is the outer shelf to upper bathyal at the lower and upper parts of formation and its extension to the middle bathyal in the middle part of the formation. Based on the stratigraphic ranges of the recorded Calcareous nannofossils biozones, the age of the Kometan Formation at Dokan area is Late Turonian-Early Campanian.

Highlights

The Kometan Formation is widely distributed during the Late Turonian to Early Campanian of northern and central Iraq (Buday, 1980)
The Kometan Formation consists of limestone, white to yellowish weathered color and sometimes yellowish in color
The lower 60 meters of the Kometan Formation consists of well bedded (15-35 cm), tough limestone of grayish white colour and free of clastic sediments, This part is characterized by the predominance of Stylolites and joints as well as the presence of pyritic nodules spread randomly in some beds, while the upper parts of this sequence are characterized by the appearance of thin beds (10-15 cm) of the black shale, interbedded between the limestone beds

Summary

Introduction

The Kometan Formation is widely distributed during the Late Turonian to Early Campanian of northern and central Iraq (Buday, 1980). This formation has been described for the first time by Dunnington (1953) in Bellen et al (1959) in the type section chosen near the villages of Kometan and AinDazah, north of the city of Rania, located in northeastern Iraq. Bellen et al (1959) determined the early Turonian-Santonian age of formation depending on the presence of Gumbelinaspp; Oligostegina; Globotruncana Helvetica Bolli (at base); G.cf renzi Gandofi; G.

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