Investigation of Main Planktonic Foraminiferal Bio-Events in Surgah Formation at Pol-e-Dokhtar Area, South Western of Iran

M Vahidinia,M Shafiee Ardestani,M Haddadi

doi:10.4236/ojg.2016.68060

Abstract

Surgah Formation at Male-kuh well section with 82 meters thickness has been studied at Pol-e-Dokhtar area. Surgah Formation at mentioned section was composed of limestone and shaly limestone. The lower and upper contacts of studied formation with Sarvak and Ilam formations are conformed. Based planktonic foraminifera study 37 species belonging to 10 genera in frame of two planktonic foraminiferal biozones were identified respectively as below: 1) Dicarinella concavata Interval Zone; 2) Dicarinella asymetrica Total Range Zone. Finally, based on recent investigation have been detected middle Turonian-Late Santonian age for studied section. According to (Robaszynski and Caron 1979), the first occurrence of Dicarinella primitiva has been shown base of the Coniacian stage. The first occurrence of Di. primitiva was placed under the Turonian-Coniacian boundary. Robaszynski and Caron 1995 recorded the first occurrence of Dicarinella primitiva and Dicarinella concavata were simultaneous and assigned to late Turonian which correlated with ammonite’s species Subprionocyclus neptuni. In the correlation between ammonite and Dicarinella primitiva at Tethyan realm first occurrence of Di. primitiva was close to the Middle-Late Turonian sub stage. The base of Coniacian stage was identified based on the FODs of Archaeoglobigerina cretacea and Dicarinella concavata from planktonic foraminifera with FOD of Cremnoceramus walterdorfensis walterdorfensis from inoceramid group, while the base of Santonian stage recorded using LOD of Dicarinella primitiva, Whiteinellids group with FODs of Dicarinella asymetrica and Inoceramus aff. vistulensis (inoceramid species).

Highlights

IntroductionZagros folded and thrust belt is considered as part of the Alpine-Himalaya Mountains [1]
The study area is located in the North East Zagros Basin
Zagros folded and thrust belt is considered as part of the Alpine-Himalaya Mountains [1]. It is 2000 km in length, from the northwest to the southeast (Oman line) [2]. This tectonic zone is characterized by three regions: 1) Uremiah-Dokhtar magmatic assemblage; 2) Zagros imbricate zone; 3) Zagros folded and thrust belt [3]

Summary

Introduction

Zagros folded and thrust belt is considered as part of the Alpine-Himalaya Mountains [1] It is 2000 km in length, from the northwest (southeast Turkey) to the southeast (Oman line) [2]. Type Locality of Surgah Formation was placed in Tang-e-Grab at southwestern Surgah montain and 12 km from southwestern of Ilam country It has 175.5 meters thickness with main lithological units of lght to drak gray shales with intracalted fine limestone [14]. Sourgah Formation at type locality has 175.5 meters thickness and consists of dark to light grey shale with some fine limestone This formation at Maleh-kuh section has 82 meters thickness with main lithological unites of shales, limestone and shaley limestone with pyrite and glaqunite. Sourgah Formation at studied section consists of 9 lithological unites respectively as follows: 1) Dark brown shaly limestone, 5 m thick. 2) Light gray lime stone, 2.5 m thick

Discossion

Findings

Conclusions