Depth variation in Farokhi Formation at the type section in the Central Iran sedimentary basin

Document Type : Original Article

Author

• Mohsen Allameh

Associate Professor, Department of Geology and Petroleum Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran

10.22067/sed.facies.2022.42015

Abstract

In order to paleobathymetry of the Farokhi Formation at type section, have been studied based on planktonic foraminifera. The thickness of this formation is 251 meters and was composed of limestone, marl, and limey marl with fossils limestone. The lower and upper contacts of studied formation with Haftoman and Choopanan formations are respectively conformed and disconform. Based on this research were realized 28 planktonic foraminifera species belonging to 9 genera. Comparing planktonic assemblages recovered from the formation with those biogeographical provinces indicate a close similarity with those of Tethyan provinces. Also, based on a statistical analysis of foraminifera assemblages, it has been proposed that Farokhi Formation was deposited at Middle-Outer Neritic open marine environment. In the Early Campanian Sea level is low and at the Middle-Late Campanian is high. At Campanian-Maastrichtian transition sea level is low and at the Maastrichtian stage is high. Finally based on a statistical analysis of %P, M3 and Van der Zwaan et al. (1990) depth equation was display Farokhi Formation was deposited at 75-meter depth.

Keywords

• Central Iran
• Farokhi Formation
• Type section
• Planktonic foraminifera
• Depth equation

Main Subjects

• Paleoecology and Extinction events
• Microfacies and Sedimentary Environments

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