Microfacies and sequence stratigraphy of Sarvak Formation in north east of Gachsaran (Tange – Gorgodar)

رخساره‌های رسوبی

Article 1, Volume 4, Issue 2, June 2011, Pages 188-198   

Document Type: مقالات پژوهشی

DOI: 10.22067/sed.facies.v4i2.9536

Authors

Elham Mahmoudi^* ; Azizollah Taheri

Abstract

In this research, facies, sedimentary environment and sequence stratigraphy of the Sarvak Formation in northeast of Gachsaran (Gorgodar Valley) was studied. The thickness of the Sarvak Formation is about 450 meters and is mainly composed of medium to thick bedded and massive limestones. Nine microfacies were identified which were deposited in three facies belts of open marine, barrier and lagoon subenvironments. The Sarvak Formation was deposited in a carbonate ramp. Three third order sequences are identified in the Sarvak Formation. The first sequence belongs to the Upper Albian-Mid Cenomanian. The boundary between the Kazhdomi and Sarvak Formations is considered as MFS. Highstand systems tract (HST) of this sequence is mainly composed of open marine microfacies. The upper boundary of the first sequence is type 2 (SB2). The second sequence is Cenomanian in age. Transgressive systems tract (TST) of this sequence is considered to be open marine microfacies, while, the highstand systems tract are composed of open marine and lagoonal microfacies. The third sequence belongs to the Upper Cenomanian. The TST of this sequence are mainly composed of lagoonal microfacies. The MFS is bar microfacies and the HST is composed of lagoonal microfacies. The upper boundary of this sequence is considered as SB1.

Keywords

Sarvak Formation; microfacies; Depositional environment; Sequence stratigraphy; Cenomanian; Gorgodar Valley