Palynology and petroleum potential evaluation of the Ab-Talkh Formation (Early Campanian - Early Maastrichtian) in Kopeh-Dagh sedimentary basin, northeastern Iran

Ab-Talkh Formation (Campanian-Maastrichtian) is one of the lithostratigraphic units of the Kopeh-Dagh basin. Marine palynomorphs (Dinoflagellates) with good preservation are found in lower and middle parts in the type section while the upper part contains few palynomorphs. In the present article in addition to palynology, seven samples from the Ab Talkh Formation in type section were selected for geochemical analysis using Rock-Eval pyrolysis. Palynology slides indicate that the Ab-Talkh Formation at the typesection was deposited in a proximal shelf to marginal basin and under an oxic, medium to high energy condition. The Rock-Eval pyrolysis results show that these samples haven’t reached the catagenesis zone (Tmax higher than 435 degrees centigrades) so they are immature. These samples contain kerogen type Ш and have poor genetic potential of petroleum generation. It should be mentioned that results from Rock- Eval pyrolysis confirm palynological results.