Iraqi National Journal of Earth Sciences

Abstract

The lithology and biostratigraphy of Bekhme Formation and lower part of Shiranish Formation have been investigated within a well – exposed section at the southern limb of Bekhair anticline, Dohuk area, north of Iraq. The section consists of marly limestone, limestone, conglomerate and marl. The lower contact of Bekhme Formation is not exposed in the studied area. The upper contact is unconformably overlain by the Shiranish Formation which consists of marl, limestone and marly limestone.The sequences of the section are characterized by rich foraminiferal faunas, where forty - eight planktonic species belonging to fourteen genera besides fifty - three benthonic species and subspecies belonging to forty genera have been recognized. The study of planktonic foraminifera resulted in the recognition of four biozones, these are from older at base:
4- Gansserina gansseri Interval Zone (part) (CF7).
3- Globotruncana aegyptiaca Interval Zone (CF8).
2- Globotruncanita stuarti – stuartiformis Partial Range Zone (CF9).
1- Globotruncanita calcarata Total Range Zone (part) (CF10).
The larger benthonic foraminiferal fauna, which appears within five stratigraphic intervals permits the recognition of: Orbitoides medius– Lepidorbitoides minor Assemblage Zone. Planktonic and benthonic zones were correlated with other zonal schemes in and outside Iraq. The studied section is appeared within late Campanian age.
Key words: Bekhme Formation, Late Campanian, Planktonic Foraminifera, Zone.