A stratigraphic section from the Tirgan Formation was selected in Arkan village nearby Bojnourd city in order to study
echinoderm fauna systematically. Many specimens of echinoderms, especially toxasteridae which is associated with
brachiopods were collected and studied systematically in this paper. Microscopie slides were also prepared and
studied. All slides contain benthic foraminifers and calcareous algae as well as gastropod and coral fragments. Based
upon diagnostic micro and macro fossils, a Barremian-Aptian age is assigned to the Tirgan Formation which suggests
Urgonien facies type indicating shallow water of open marine environment.
کلید واژگان :
Tirgan Formation; Echinodermata; Kopeh-Dagh; Barremian-Aptian; Urgonien facies type
