In order to lithostratigraphic,  microbiostratigraphic and paleoecologic study of the Gurpi Formation, Tang-e Zanjiran section located at Southwest of Kavar (southeast Shiraz) in Fars Province, has been selected. The Gurpi Formation in the Tang-e Zanjiran section with a thickness of 362.5 meters consists of calcareous shale, marly limestone, limestone, shale and marl, and can be subdivided into five informal members. The Gurpi Formation overlies the Ilam Formation conformable and overlies the Pabdeh Formation disconformable. In this research, 188 samples including 148 samples belong to strict samples and 40 samples belong to soft samples were studied. According to foraminiferal studies, 56 species belonging to 48 genera of planktonic foraminifera were identified. Based on studied foraminifera, the Gurpi Formation in the study section has Santonian-Middle Maastrichtian age. The Gurpi Formation in studied section is comparable with Caron's (1995) biozonation and can be considered 7 biozones based on planktonic foraminifera, biozones 1-6 belong to the Gurpi Formation and biozone 7 belongs to the Pabdeh Formation as follow:
1- Dicarinella concavata Total Rang Zone.
2- Globotruncanita elevata Partial Rang Zone.
3- Globotruncana ventricosa Interval Rang Zone.
4- Radotruncanacalcarata Total Rang Zone.
5- Globotruncana aegyptiaca Interval Rang Zone.
6- Gansserina gansseri Total Rang Zone.
7- Morozovella velascoensis Total Rang Zone.
Based on life-depth of identify fauna from Zanjiran stratigraphic section, three groups of cretaceous morphotype belong to epicontinental sea fauna, shallow water fauna and deep water fauna were identified. The Comparison of identified fauna from Gurpi formation with cretaceous biogeographic province and paleogeography map, it can be resulted this lithological section was precipitated in tethys province and warm weather as well, therefore, the condition of sedimentation could be in a deep-water environment with more than 100 meters.