New Founds in Biostratigraphy of Tarbur Formation at Semirom area (south-western Isfahan)

The Maestrichtian rudist-bearing Tarbur Formation with abundant large foraminifera was deposited in Zagros basin. For studying of the Tarbur Formation in the Fars province, the deposits of Tarbur Formation in 5 Km to south west of Semirom was sampled and studied. The Semirom area is located in the east of Zagros Mountain; in the interior Fars of the High Zagros. In the studied area the Tarbur Formation with 462 m thickness, composed of carbonate and terrigenous rocks. Tarbur Formation has a gradual and conformable contact with red shale of red detritus unit (S2) and the upper boundary with Kashkan Formation is marked by an erosional surface.
On the basis of fossil assemblages from the Tarbur Formatin, the identified Biozone is Omphalocyclus-Loftusia-Siderolites calcitrapoides assemblage Zone. The biostratigrphic data based on benthic and planktonic foraminifera and rudists represents the late Maestrichtian age for the study section. Among distinguished foraminifers and rudists, Omphalocyclus cideensis, Omphalocyclus anatoliensis, Pseudomphalocyclus blumenthali, Elphidiella multiscissurata, Sirtina orbitoidiformis, Rotalia skourensis, Loftusia anatolica, Loftusia persica, Pseudedomia sp., Laffitina sp. and Hippurites cornucopiae reported for the first time at the deposits of Tarbur Formation in Semirom section of Isfahan.