Biostratigraphy and Paleoecology of the Mobarak Formation at the Mighan section (the northeast Shahroud) based on the benthic foraminifers

Document Type : مقالات پژوهشی

Authors

• Maryam Sadeghzadeh ¹
• Mahmoud Sharafi ²
• Hossein Mosaddegh ³

¹ M.Sc. in Stratigraphy and Pelaeontology, Faculty of Geology science, Damghan University, Damghan, Iran

² Assistant Professor, Faculty of science, Department of Geology, University of Hormozgan

³ Associate Professor, Faculty of Geology, Kharazmi University, Tehran, Iran

10.22067/sed.facies.2021.47062.0

Abstract

The Carboniferous sedimentary sequence at the Mighan section with 450 m thickness are studied with respect to the microfossils specially foraminifers and biozones. Based on the stratigraphic distribution of the index species, the age of the Mobarak Formation in the studied section is identified as the Late Tounaisian (Ivorian)- middle Visean (Moliniacian). With studying and identification of the foraminifers, Tounaisian- Visean stages boundary and their evolution trend until the end of the Lower Carboniferous sedimentation are studied. Five foraminifer biozones, GZ1-GZ5, are introduced for the Mobarak Fm. in the studied locality, which can be compared to the Belgium and the north France biozones, respectively. The most important ecologic and environmental factors that directly affect the distribution, abundance and lifestyle and the mode of preservation of biota and trace fossils are consist of oxygen level, light, salinity and nutrients during the deposition of the carbonate sediments of the Mobarak Formation. Achieved results in this research provide valuable information of the distribution of the bio/ facies associations, lifestyle and manner of the prevailing organisms (benthic, feeding and suspension feeding) and their reaction to the dominated sedimentary processes and changes in the sedimentary environment conditions in the various parts of the carbonate systems and their controlling factors.

Keywords

• Alborz Basin
• Mobarak Formation
• Late Carboniferous
• Biostratigraphy
• Ecology

Main Subjects

• Systematic Paleontology & Biostratigraphy
• Microfacies and Sedimentary Environments

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