Microbiostratigraphy of the lower Cretaceous strata from South East of Maragheh, NW Iran

Abstract

For the microbiostratigraphical studies, a stratigraphical section (named Dareh-Goshayesh) has been selected in southeast of Maragheh, Northwestern Iran. The thickness of successions in the selected stratigraphic section is measured about 223.6 m. The mentioned studied stratigraphic section is composed of two clastic and carbonate units. This succession unconformably overlies the Lar Formation and is overlain by the Upper Cretaceous strata paraconformably. Based on the micropaleontological studies, a diversified assemblage of foraminifera and calcareous algae has been determined and the age of the studied stratigraphic section is inferred as Late Barremian-Late Aptian. Also, during these studies, four biozones are determined as follows: <em>Palorbitolina</em> <em>lenticularis</em> Range Zone, <em>Balkhania balkhanica</em> range zone, <em>Orbitolina</em> (<em>Mesorbitolina</em>) <em>texana</em> Zone and <em>Orbitolina</em> (<em>Mesorbitolina</em>) <em>parva</em> Zone. This paper presents the first micropalaeontological and lithostratigraphical studies.