Kharazmi Journal of Earth Sciences

Kharazmi Journal of Earth Sciences

Biostratigraphy of Upper Cretaceous Deposits in the Bahabad Stratigraphic Section, Southwestern Bajestan (NE Iran)

Authors
Abbas Sadeghi 1
Zahra Rezazadeh 1
Mahbobeh Hooseni- Barzi 1
Ahmad Reza Khazaei 2
1 Shahid Beheshti University
2 Birjand University
10.52547/gnf.6.1.169
Abstract
In order to study the biostratigraphy of the Upper Cretaceous deposits in north of Lut block, one stratigraphic section in Bahabad south-west Bajestan area was selected and sampled. The thickness of the Upper Cretaceous deposits in this section is 152.48 meters and based on lithological changes it is divided into five rock units: clastics rocks, gypsiferous marl, lower limestone, marl and upper limestone. The lower boundary due to lack of outcrop is not recognizable and the upper boundary underlies the recent erosional deposits. In biostratigraphic studies with the exception of two basal rock units that have no fossils in the other three rock units: lower limestone, marl and upper limestone 53 genera and 47 species of benthic foraminifera were recognized and two biozones identified as follows:

Biozone 2: Rotorbinella campaniola- Pararotalia tuberculifera- Pseudocyclammina massiliensis assemblage zone

Biozone 1: Rotorbinella mesogeensis- Pararotalia boixae- Dicyclina sampoi assemblage zone.

According to the determined biozones and fossils associations the age of four basal rock units are Cenomanian and upper limestone unit is Santonian- Early Campanian. A sedimentary gap is visible during Turonian- Coniacian between marl and upper limestone rock units in this section.
Keywords
Biostratigraphy
Upper Cretaceous
Lut Block
Bahabad
Bajestan
Northeast of Iran
Subjects
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Kharazmi Journal of Earth Sciences
Volume 6, Issue 1 - Serial Number 11
August 2020
Pages 169-182