Iraqi National Journal of Earth Science

Planktonic foraminiferal biostratigraphy of Shiranish Formation was studied in Sarah's anticline at the Dokan area, Sulaymania governate in, northeastern Iraq. The studied section consists of marl and marly limestone, Sixty-three Planktonic foraminiferal species belonging to seventeen genera have been recognized which permits the recognition of six zones; these are from older at the base
6- Abathomphalus mayaroensis interval zone (Part).
5- Gansserina gansseri interval zone.
4- Globotruncana aegyptiaca interval zone.
3-Globotruncanella havanensis interval zone.
2- Globotruncanita calcarata total range zone.
1-Globotruncana ventricosa interval zone (Part).
The Planktonic foraminiferal zones were correlated with other zonal schemes in and outside Iraq. They are considered to be extending from Middle Campanian to Late Early Maastrichtian.

67 planktonic foraminiferal species were identified from the Shiranish Formation. On the basis of the stratigraphic distribution of the planktonic foraminiferal assemblages recognited of six biozones within the Shiranish Formation representing an age ranging from Middle Campanian – Early Maastrichtian, these zones are from older at base:
6 -Planoglobulina acervulinoides Interval Zone.
5 - Contusotruncana contusa Total Range Zone.
4 -Gansserina gansseri Interval Zone.
3 - Globotruncana aegyptiaca Interval Biozone.
2 -Globotruncanella havanensis Interval Biozone.
1 -Globotruncana ventricosa Interval Biozone

Ostracode biostratigaphy were investigated in detail from three formations (Shiranish, Hartha and Mushorah ) in subsurface sections of four boreholes Northwest and centre of Iraq.
On the basis of the ostracode species distribution, the studied formations were divided into four ostracode biozones as follows:

Biozone 1: Cytherella IRC 22 Interval zone. (Early Campanian).
Biozone 2: Occultocythereis elongata Interval zone. (Late Campanian).
Biozone 3: Krithe sp. M 1113 Interval zone. (Early Maastrichtian).
Biozone 4: Holcopocythere bassiporosa Interval zone. (Late Maastrichtian).

Depending on the above biozones correlated with other previous works from Iraq and the Middle East regions the following ages were proposed for the studied formations:

Shiranish Formation: Late Campanian - Maastrichtian.
Hartha Formation: Late Campanian - Early Maastrichtian.
Mushorah Formation: Early Campanian.

The contact between Bekhme and Shiranish Formations is studied paleontologically in Bekhme gorge and Rawanduz area. The nannofossils are used to prove that the age of the base of the Shiranish Formation is lower late Campanian and middle Campanian in Bekhme gorge and Rawanduz area respectively. The older age of the Rawanduz area is attributed to early drowning (flexing downward) of the forebulge of the Arabian platform due to southwest propagation of tectonic load of the Zagros Orogen during early stage of collision of Afro-Arabian and Iranian plates by which the Tethys ocean closed later.

Planktonic foraminifera are studied from Shiranish Formation in Kirkuk well No.(306) , north of Iraq between depth interval( 1540-1660 m). Detailed study of the planktonic foraminifera revealed (25) species. The stratigraphic distribution of the Planktonic foraminifera recorded in the section permits the recognition of four zones these are from olderat the:

4- Gansserina gansseri Interval Zone ( Part).
3- Globotruncana aegyptiaca Interval Zone .
2- Globotruncanella havanensis Partial Range Zone.
1- Globotruncanita calcarata Total Range Zone ( Part) .

The zones are correlated with other studies inside and outside Iraq .The present work indicats that Shiranish Formation is of Late Campanian to Early Maastrichtion age.

The litho-and biostratigraphy of Shiranish Formation have been investigated within a well-exposed section at the southern limb of Bekhair anticline, Dohuk area, Northern Iraq. The studied section consists mainly of marl, marly limestone, and limestone. The Formation unconformably overlies Bekhme Formation and it is overlain unconformably by the Kolosh Formation. The samples of the section under investigation yielded rich and well diversified planktonic foraminiferal taxa, where 55 planktonic species belonging to 16 genera have been recognized, the detailed foraminiferal investigation permits the recognition of 8 well defined zones. These are from older at the base:

8. Plummerita hantkeninoides Total range Zone (Part).
7. Pseudoguembelina palpebra Partial range Zone.
6. Pseudoguembelina hariaensis Interval Zone.
5.Racemiguembelina fructicosa Interval Zone.
4. Planoglobulina acervulinoides Partial range Zone.
3. Contusotruncana contusa Interval Zone.
2. Gansserina gansseri Interval Zone.
1. Globotruncana aegyptiaca Interval Zone (Part).

The Planktonic zones were correlated with other zonal schems in and outside Iraq. They are considered to be extending from middle Late Campanian to latest Maastrichtian.

Planktonic foraminifera is studied from Shiranish Formation in Makhmur
well No. (1), North Iraq between the depth interval (657-620) m. Three
biostratigraphy Zones are recognized in these formation:
1. Globotruncanita elevata–Rosita fornicata Zone.
2. Globotruncana aegyptiaca Zone.
3. Gansserina gansseri Zone.
20 عبد الله سلطان شهاب الحدیدی
The results of this study are compared with the work of others inside and
outside Iraq. The age of the Shiranish Formation in the said well is Late
Companian to Early Maastrichtian.

Eighteen plankonic foraminiferal species belonging to five genera have been identified within the studied section of Shiranish Formation in Butmah well no.15; which is divided into four biozones. The first zone represents the Late Campanian age while the other three zones extend within the Early and Middle Maastrichtian age These zones are:
-Gansserina gansseri Zone
-Globotruncana aegyptiaca Zone
- Globotruncanella havanensis Zone
-Globotruncanita calcarata Zone
The age of the studied section in Butmah well no.15 has been fixed as Late Campanian to Middle Maastrichtian while the upper part of the Middle Maastrichtian and the whole Upper Maastrichtian are missing. According to this fact the contact surface between Shiranish and Aaliji Formations is an unconformity surface.