Microfacies, depositional environment and sequence stratigraphy of the Mishan Formation in South of Kavar

Mishan Formation with a thickness of 395 meter which is composed of limestone, marly limestone and marl and early to middle Miocene age (Burdigalian-Langhian), has been measured and sampled in order to study the sedimentary environment and sequense stratigraphy in Bavarian stratigraphic section in the south of Kavar, Fars province. The Mishan Formation is located on the red evaporative and clastic sequence succession of the Razak Formation and under the clastic and carbonate succession of Agha Jari Formation (Miocene-Pliocene age). Based on the characteristics of petrographic features, field evidence, as well as examining the abundance and distribution of foraminifera and other other allochems and orthochems, eighteen microfacies packages were identified in six sub-environments or sedimentary zones (Facies zones) including tidal flat, lagoon, shoal, pach reef, shallow and deep open marine can be placed. The absence of barrier reefs (which are typical of rimmed platforms) and re-deposited carbonates and also gradual conversion of microfacies into each other and the existence of wide areas of tidal, indicate that the sedimentary sequence in this section was deposited on a homoclinal ramp carbonate platform. The sedimentation of limestone-marl deposits of Mishan Formation on the evaporite-clastic sedimentary rocks of Razak Formation, indicate the last transsgresion of the sea water during the Miocene age of the Zagros Basin. The investigation of the sequence stratigraphy of this Formation in the research section has led to the identification of four third-order sedimentary sequences with sequence boundaries of the second type.