The Sarvak Formation (Albian to Cenomanian), forming part of the Bangestan Group, comprises a thick succession of carbonate rocks in the Zagros Basin of Southern Iran. The type section of the Sarvak Formation is situated in the Teng-e-Sarvak area, Khuzestan, and is overlain by the Kazhdumi Formation and underlain by the Ilam Formation. The boundary between Sarvak and Ilam Formation is a disconformity that determined in some area by breccia or conglomerates.
The Sarvak Formation consists of alternation of limestone, shale and marl. Limestone layers of this formation are full of microorganisms known as orbitolina. and Because of more than 60% calcium carbonate in their composition, they have a lot of talent for karstification.
The above image shows outcrop of Sarvak formation at the core of the Chenareh anticline near Pa-alam in Khuzestan province. alternation of well-bedded limestone and thin layers of shale and marl is seen in the picture. Due to the presence of thin layers of marl and shale in its sedimentary sequence, The Sarvak Formation has been eroded very soon and the land is hilly shape.
In the picture above, outcrop of Sarvak Formation is seen in the core of Chenareh anticline in bright color.
Geological map of Chenareh anticline (Part of the geological map Balarood)