Palynostratigraphy and palynofacies studies of the Sanganeh Formation at the Dahaneh Gholaman section, Central Koppeh-Dagh

The Sanganeh Formation is one of the Early Cretaceous rock units in the Koppeh- Dagh basin. This formation in the Dahaneh Gholaman section (in north of Bojnord city) with a thickness of 900 meters (consist of marl, shale and limestone) is laying conformably on the Sarcheshmeh Formation and covered by Atamir Formation. In this study, biostratigraphic investigations on 50 palynological samples from the Sanganeh Formation led to recognition of 21 genera and 31 species of dinoflagellate cysts indicating an age of Late Aptian-Albian belonging to Odontochitina operculata zone. Also palynofacies studies revealed two types of palynofacies (II and IV). Palynofacies studies show dominance of palynofacies II through the stratigraphic column indicating a marginal dysoxic-anoxic basin. On the other hand, presence of palynofacies IV in some parts along the stratigraphic column reflects increase in the depth of the marine environment from time to time.