Document Type : Original Research Paper


1 Professor, Faculty of Science, Department of Geology, University of Esfahan, Esfahan, Iran

2 Assistant Professor, Faculty of Science, Department of Geology, University of Esfahan, Esfahan, Iran

3 M. Sc.Student, Faculty of Science, Department of Geology, University of Esfahan, Esfahan, Iran

4 Assistant Professor, Depatment of Geology, Faculty of Science, University of Birjand, Birjand, Iran

5 Associate Professor, Faculty of Earth Science, Shahrood University of Technology, Shahrood, Iran


In order to study the biostratigraphy and palaeoecology of the Maestichtian deposits (Tarbur and Gurpi formations) in High Zagros, Gardbishe section in south of Borojen was selected. The Tarbur deposits in this region are mainly composed of carbonate and clastic a rock which has been overlaind by Gurpi Formation. The lower contact of this formation is lower red unit as conformable contact. The Gurpi Formation is lithologically composed of marl which has been overlaind as a disconformable contact by Shahbazan dolomites. The biostratigrphic data based on benthic and planktonic foraminifera and rudists represents the late Maestrichtian age for the section. Two biozones were identified in Maestrichtian deposits including: Omphalocyclus-Loftusia assemblage zone, Contusatruncana contusa-Recemiguembelina fructicasa zone. In general, the suitable environmental conditions for diversity, frequency and increase in size of some fossils such as Loftusia and in the absence of some other fossils such as Orbitoides and Lepidorbitoides in this region can be related to augmentation of nutrients and entering the detrital and silica sediments due to river injection and runoff and consequently to the eutrophic conditions formed in the basin.


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