Facies Analysis, Depositional Environment and Diagenetic Features of the Qom Formation in the Saran Semnan, Central Iran

Parviz Ghazanfari,Mohsen Aleali,Fereshteh Karami-Movahed

doi:10.4236/ojg.2016.66030

Abstract

In this study, to identify and analyze facies of depositional environment and depositional model of Qom Formation, stratigraphic Saran Section (southwest of Semnan) was selected. Qom Formation in Saran section includes about 380 meters of conglomerate at the base, chalk, limestone, marl, and shale. Petrographic studies with facies analysis have led to the identification of 12 microfacies, these microfacies have been deposited in four facies groups including tidal flat, lagoon, barrier and open marine. Study of horizontal and vertical facies changes and their comparison with recent and ancient environments reveals that Qom Formation in this section relates to shallow marine environment and its facies were deposited in a shelf carbonate platform and are comparable with contemporary shelf platforms such as Florida and old shelf platforms such as Mozduran. The most important diagenetic processes affecting the studied section include micritization, bioturbation, cementation, dissolution, neomorphism, fracturing, mechanical and chemical compaction, hematitization and dolomitization. These processes have formed in marine, meteoric and burial diagenetic environments.

Highlights

Qom Formation (Oligo-miocene) is composed of clastic and carbonate sediments
Following the Pyrenean event and a continental sedimentation in the lower Oligocene, a beam of west central Iran to the south Jazmurian shuttle has been covered with a progressive sea
Diagenetic Features Based on sedimentary-petrographic analysis of the Qom Formation several diagenetic features are identified in the studied thin section include micritization, bioturbation, cementation, dissolution, neomorphism, fracturing, mechanical and chemical compaction, hematitization and dolomitization which are discussed separately

Summary

Introduction

Qom Formation (Oligo-miocene) is composed of clastic and carbonate sediments. (2016) Facies Analysis, Depositional Environment and Diagenetic Features of the Qom Formation in the Saran Semnan, Central Iran. Following the Pyrenean event and a continental sedimentation in the lower Oligocene, a beam of west central Iran to the south Jazmurian shuttle has been covered with a progressive sea. The subduction has created the backarc opening in the center and north central Iran and the marine sediments of the Qom Formation is made up with alkaline magmatic activity. Materials and Methods The present paper is based on field and laboratory examination of the Qom Formation from the Saran Semnan section. For recognize diagenetic features and processes fundamental diagenetic definitions were applied

Carbonate Components

Microfacies Description and Interpretation

Findings

Conclusions