Dinoflagellate and Paleoenvironment Study of Dalichai Formation in East Part of Binaloud Sedimentary Basin

The Dalichai Formation is among marine deposits in Jurrasic period that has a geographic expansion in north of Iran. In order to palynological studies in eastern part of the Binaloud Mountains an outcrop of this formation, in the bar village was selected. The thickness in bar village section is 255 meters includes dark gray shales. The study of 112 slides of 28 samples taken from this formation showed that the most of the samples contain palynomorphs specifically dinoflagellates. 53 species belonging to 27 genera of dinoflagellates were identified. According to dinoflagellates, a middle Jurassic age was determined for the Dalichai Formation in the Bar village section. Based on the study of three main groups of phytoclasts, marine palynomorphs and amorphic organic matters and result of the statistical studies of different factors, sedimentary environment of the Dalichai Formation in studied section was open marine basin with shallow and low oxygen condition.