Sequence Stratigraphy of Oligo-Miocene deposits at Ahmadi anticline, southeast of Shiraz

The sequence stratigraphic studies can be of great help in understanding and analysis of sedimentary basins. For this purpose, Oligo-Miocene sediments (Razak and Asmari formations) at the Tang-e-Abdi section (southern flank of Ahmadi anticline) located in Fars province was selected and investigated. The Asmari Formation overlies paraconformably on the Jahrum Formation, and it is overlain by the Razak Formation. The lithologic column of this section includes a succession of the Jahrum (10m), Asmari (35m) and Razak (172.5m) formations, and consists mainly of limestone, argillaceous limestone, marl, sandstone, conglomerate, shale and dolomitic deposits. Totally, 84 samples were investigated, and their age is suggested as Late Eocene for the Jahrum Formation to Rupelian for the Asmari sediments, and Rupelian to Aquitanian for the Razak Formation based on the benthic foraminiferal stratigraphic distribution. The microfacies studies were led to recognition of four facies belts including tidal flat, lagoon, sand shoals and open marine. According to field & laboratory studies, four sequences and sequence boundaries were recognized. Two sequence boundaries are of type one and the other two are of type II sequence boundaries.