Fatemeh Hadavi - Department of Geology, Ferdowsi University, Mashhad, Iran
Khosro Khosrowtehrani - Department of Geology, Faculty of Basic Sciences, Sciences & Research Branch, Islamic Azad University, Tehran, Iran
Ali Aghanabati - Department of Geology, Islamic Azad University - North Tehran Branch, Tehran
Mohammadreza Baniasadi - Department of Geology, Faculty of Basic Sciences, Sciences & Research Branch, Islamic Azad University, Tehran, Iran

This research studied the biostrigraphy of Upper Cretaceous deposits (Santonian - Masstrichtian) regarding to Coccolithophorids South east Isfahan, Central Iran. Nannofossils out of two sections from south and south-east Isfahan had good preservation and high variety. Lithostratigraphic unit have different thicknesses that, include marly limestone, shale, and limestone. Fine grained sediments, normally consisting of shale and marly limestone, have the best chance to contain nannofossils with respect to their content in calcareous nannofossils. The following genera and species were identified from deposits:Arkhangelskiella cymbiformis, Biscutum magnum, Braarudospheara sp., Calculites obscurus, Ceratholitoides self-trailiae, Ceratolithoides aculeus, Ceratolithoides amplector, Ceratolithoides brevicornicalans, Ceratolithoides kamptneri, Ceratolithoides pricei, Ceratolithoides sp., Cyclagelosphaera margerelii, Lithraphidites carniolensis, Lithraphidites quadratus, Lucianorhabdus cayeuxii, Lucianorhabdus maleformis, Micula murus, Micula praemurus, Micula prinsii, Nannoconus dauvillieri, Quadrum gartneri, Quadrum trifidus, Thoracosphaera opercula, Watznaueria barnesae.Most of them have good preservation and high variety. Totally ۱۶ genera, ۲۶ species related to the calcareous nannofossils have been identified.

Coccolithophorids, Nannofossil, South east Isfahan, Upper Cretaceous