African Journal of Geography and Regional Planning

African Journal of Geography and Regional Planning ISSN 3627-8945 Vol. 7 (6), pp. 001-009, June, 2020. © International Scholars Journals

Full Length Research Paper

Microfacies and sedimentary environment of the Oligo-Miocene sequence (Asmari Formation) in Khuzestan sub- basin, Zagros Basin, southwest Iran

Mahnaz Parvaneh Nejad Shirazi¹*, Mohsen Davoudi Nezhad² and Hormuz Ghalavand³

¹’²Department of Geology, Payame Noor University, PO BOX 19395-3697 Tehran, IRAN.

³National Iranian South Oil Company (NISOC)

Accepted 09 May, 2020

Abstract

The Asmari Formation is a thick carbonate succession of the Oligo-Miocene in Zagros Basin. The Oligocene-Miocene Asmari Formation, Chidan area, is composed of limestone and calcareous marl. The Asmari Formation has a conformable contact with the overlying (Gachsaran Formation) and the underlying (Pabdeh Formation) units and is subdivided into three members. In order to interpret the facies and depositional environment of the Asmari Formation, two measured sections were studied in Chidan area for microfacies analyses. In this study, eight different microfacies types have been recognized on the petrographic studies, field observations, identification of larger foraminifera and facies studies of the Asmari Formation (Chidan section). These carbonate microfacies belonging to four major subenvironments: open marine (A), bar/shoal (B), lagoon (C) and tidal flat (D). The depositional environment of the Asmari Formation is interpreted as a shallow carbonate ramp. The most of the Asmari Formation in the study area was deposited in an inner ramp environment.

Keywords: Asmari Formation, Chidan, Gachsaran, Pabdeh, Iran.