Microbiostratigraphy of the Sarvak Formation (Cenomanian) in the Aghar and Homa wells in sub-coastal and coastal Fars, (south of Iran)

To investigate biostratigraphy on the Sarvak Formation in coastal and sub-costal Fars (south of Iran), two subsurface stratigraphic section were selected. The selected sections are Aghar and Homa wells which are located in sub-coastal Fars and coastal Fars, respectively. Aghar well is located in the northwest of Ghir in Iran and the Sarvak Formation is observed from the depth of 787–1046 m and its thickness is 259 m, and Homa well is located in the Homa gas field which can be observed from the depth of 679–769 m and its thickness is 90 m. In terms of lithostratigraphy, the Sarvak Formation in these wells is composed of limestone in the lower part and limestone and shale in the upper part; furthermore, its lower lithostratigraphic limits in these wells with the Kazhdumi Formation are conformable, and the upper limit in the Homa well is covered unconformably by the Ilam Formation and the Aghar well is covered unconformably by the Laffan Formation. Biostratigraphy study in the Aghar and Homa wells revealed the occurrence of 18 genera and 20 species of both planktonic and benthic foraminifera. Besides, the following biozones in the Aghar well were identified in our biostratigraphical studies: Trocholina – Orbitolina assemblage zone (Late Albian-Early Cenomanian), Upper Kazhdumi–Lower Sarvak formations, Nezzazata –Alveolinids assemblage zone (Middle-to-Late Cenomanian), Upper Sarvak (Lower Ahmadi member (, Oligostegina biozone (Late Cenomanian), and Upper Sarvak (Upper Ahmadi member). Also in the Homa well, two biozones were identified which are Trocholina Orbitolina sp. assemblage zone (Late Albian-Early Cenomanian) and Nezzazata – Praealveolina cretacea assemblage zone (Middle-to-Late Cenomanian).