Microfacies Patterns and Depositional Environments of the Sarvak Formation in the Abadan Plain, Southwest of Zagros, Iran

Shahab Soleimani Asl,Mohsen Aleali

doi:10.4236/ojg.2016.63018

Shahab Soleimani Asl, Mohsen Aleali

Open Access

https://doi.org/10.4236/ojg.2016.63018

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Abstract

The Sarvak Formation is the second major oil-bearing reservoir in the south and south west of Iran. The Middle Cretaceous Sarvak formation in the Zagros Mountains (Zagros Basin) is mainly composed of carbonate sequences. Based on facies studied, thirteen microfacies were recognized in the studied area, which were categorized in the three facies groups: including inner ramp, mid ramp and outer ramp. Evidences such as the gradual changes in the facies (basin slope), the absence of extensive uninterrupted barrier reef, the lack of calciturbidite and gravity sediments as well as the high proportion of grain-supported indicated that the Sarvak Formation was deposited in the ramp like depositional system, particularly on an inner ramp setting. Inner ramp facies group is the principal setting and subdivided to tidal flat, restricted and unrestricted lagoon as well as shoal sub-environments.

Highlights

Zagros basin is known as one of the most petroliferous regions in the world in term of hydrocarbon potentials [1]
Sarvak Formation is a part of Bangestan group
The Zagros fold and thrust belt with nearly 1800 km long and 250 km wide composed of deformed rocks that created in the foreland of the collision between the Arabian Plate and the Iranian Plate [18] [19]

Summary

Introduction

Zagros basin is known as one of the most petroliferous regions in the world in term of hydrocarbon potentials [1]. Sarvak Formation is a part of Bangestan group. The Kazhdumi, Sarvak, Surgah as well as the Ilam Formations with middle to upper Cretaceous age formed the Bangestan group in the south and southwest of Iran [2]. The type section of Sarvak Formation is located in the northwest of the Behbahan city in. Sarvak Formation is composed of over 820 m of thin, medium bedded and massive limestone containing chert nodules and interbeds of shale. According to distribution of foraminifer contents in the type section [2] mentioned Albian to cenomanian age for Sarvak Formation) [2]. The lower boundary of the Sarvak Formation with the Kazhdumi Formation is sharp, in the Zagros province. In some parts of Zagros Ilam Formation and in the other parts Gurpi Formation covers Sarvak limestones. The aims of current article are 1) assign detailed microfacies type, 2) interpret the facies, 3) determine different setting of facies and 4) delineate depositional environment model

Geological Setting

Materials and Methods

Microfacies Description and Interpretation

Depositional Environment

Findings

Conclusion