Biostratigraphy of the Grupi Formation (Santonian-Maastrichtian) by Using the Globotruncanellidae and Globotruncanidae in Bachun Area, Zagros Mountains, Iran

Studying of the Globotruncanindae and Globotruncanellidae of the Gurpi Formation in Bachun area ( south of Shiraz) led to the identification of 8 biozones, i.e., Concavatortruncana asymetrica Zone (Santonian), Globotruncanita elevata Zone (Early Campanian), Globotruncanita ventricosa Zone (Middle to Late Campanian),Radotruncana calcarata Zone (Late Campanian), Globotruncana falsostuarti Zone (Late Campanian), Globotuncana aegyptiaca Zone (Late to latest Campanian),Gansserina gansseri Zone (Latest Campanian to Early Maastrichtian), and Globotruncanita conica Zone (Early to Late Maastrichtian). Considering these biozones, the age of the Gurpi Formation in the studied section was determined Santonian to late Maasstrichtian. In this stratigraphic section, the Gurpi Formation was 371 meters thick and consisted mostly of shale with intermediate marn layers.

Keywords:

Gurpi Formation , Globotruncanidae , Globotruncanellidae , biozonation , Zagros , Iran