Bio- and sequence stratigraphy and microfacies analysis of the Oligocene Asmari Formation at Sepidar Anticline, Interior Fars sub-Basin, SW Iran

Abstract

In this research, biostratigraphy, microfacies analysis and sequence stratigraphic framework of the Asmari Formation are discussed at Sepidar Anticline, Interior Fars sub-Basin. The strata are Rupelian to Chattian in age. According to the distribution of benthic foraminifera, two assemblage zones were recognised (I-) Nummulites vascus–Nummulites fichteli and (II-) Archaias asmaricus/hensoni–Miogypsinoides complanatus. Eight microfacies types which can be grouped into three depositional environments are recognised. Distribution of Oligocene foraminifera together with other constituents allowed the identification of three third-order sequences at Asmari Formation. Correlation of analysed sections through Interior Fars sub-Basin represents the development of a carbonate ramp with a deepening trend from SE to NW along the Rupelian/Chattian boundary.

Keywords::

• Asmari Formation
• Interior Fars sub-Basin
• Rupelian–Chattian
• microfacies
• sequence stratigraphy

Acknowledgements

The author is grateful to Shiraz University for providing financial support and would also like to thank Prof. H. Vaziri-Moghaddam from the Isfahan University and Prof. F. Moore from the Shiraz University for their helpful suggestions. Warm thanks are due to the reviewers for their helpful and constructive comments.

Disclosure statement

No potential conflict of interest was reported by the author.