Microfacies analysis and depositional environment of khurmala formation (paleocene-lower eocene)‎, in the Zenta village, Aqra district, Kurdistan region, Iraq

Abstract EN

Microfacies and environmental analysis of khurmala formation (Paleocene-lower eocene) was studied in the zenta area, near zenta village, aqra district-kurdistan region northern Iraq.

the formation is composed of 71 m thick bedded grey dolomitic limestone, partially bituminous with chert nodules and rare chert lenses and medium to thick bedded yellow limestone, interbedded with thin beds of marl and mudstone.

the petrographic study showed the majority of the limestones are carbonate mud (micrite).

the skeletal grains consist principally of benthonic foraminifera, calcareous green algae, ostracods, gastropods, pelycepods, and rare larvae echinoids.

non skeletal grains include peloids only.

three main microfacies were distinguished in the limestones of the studied section and two different lithological units were recognized, based on field evidence and petrographic study.

they are in ascending order: thick bedded dolomitic limestone unit and bedded limestone with marl unit.

evidence derived from petrographic study, facies and textural analyses suggest that the khurmala formation was deposited in a shallow marine environment of shelf lagoon with circulation, under quiet and semi restricted conditions.