J. Bio. & Env. Sci. 2017 224 | Rehman et al. RESEARCH PAPER OPEN ACCESS Sedimentology of pir koh formation exposed at Dholi and Rakhi Gaj, Central Sulaiman Range, Pakistan Saif Ur Rehman*, Muhammad Ahmad Riaz, Mahboob Ahmed, Muhammad Fahad Ullah, Muhammad Kashif, Faisal Rehman Department of Earth Sciences, University of Sargodha, Sargodha, Pakistan Article published on December 30, 2017 Key words: Sulaiman Range, Microfacies, Depositional environments, Ramp Abstract Middle Eocene Pir Koh Formation is well exposed throughout the Sulaiman Range and acts as good hydrocarbon reservoir. In present research, two sections of Pir Koh Formation exposed at Dholi and Rakhi Gaj have been investigated for detailed sedimentological studies to depict the depositional environments and modeling. The formation is mainly composed of off-white to creamy white limestone and marl with black chert at places. Petrographic analyses show that Pir Koh Formation is composed of a rich assemblage of benthic and planktonic foraminifera with minor bioclasts. Four microfacies including Planktonic Wacke-Packstone microfacies, Marl microfacies, Discocyclina-Nummulities Wacke-Packstone Microfacies and Chert microfacies were framed with help of petrographic data. The microfacies analyses and paleoecology of fauna suggest a ramp model for the deposition of Pir Koh Formation and it was deposited over mid ramp to upper slope settings. * Corresponding Author: Saif Ur Rehman saif.rehman@uos.edu.pk Journal of Biodiversity and Environmental Sciences (JBES) ISSN: 2220-6663 (Print) 2222-3045 (Online) Vol. 11, No. 6, p. 224-234, 2017 http://www.innspub.net