Biostratigraphy and Sea Level Change in the Turonian -Campanian Deposits of the Central Iran Basins (Bahar Section) based on Planktonic Foraminifera

Abstract

In this study the Upper Cretaceous sediments in the Central Iran Basins, Isfehan province, the Bahar Section, were investigated for the purpose of biostratighraphy and sea level change studies. These sediments, thickness consist of marl and limy marl about 89 m. The investigated foraminifera led to identification of  30 species of planktonic foraminifera that belonged to 11 genera. Based on planktonic foraminifera the Upper Cretaceous deposits were divided into 6 biozones which were cosmopolitan and listed respectively are:biozone1 as Marginotruncana sigali - Dicarinella primitiva Partial Range zone; Biozone2: Dicarinella concavata Interval Zone; Biozone3:  Dicarinella asymetrica Total Range Zone; Biozone4: Globotruncanita elevata Partial range zone; Biozone5: Globotruncana ventricosa Interval Zone and Biozone6: Radotruncana calcarata Interval zone. The Upper Cretaceous sediments in the study area on the basis of Planktonic Foraminifera are of the Late middle Turonian to the Late Campanian ages. According to the Morphotype groups of planktonic foraminifera deeping the basin from the Middel Turonian to the Middle Santonian is seen. However, in the late Santonian shallowing the basin and again in the Early Campanian deeping the  basin, in the Late Campanian and close to the Campanian-Maastrichtian boundary shallowing the basin and a sea regression is observed. 

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منابع
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