Biostratigraphy and paleoecology of the e Member of the Qom Formation based on Ostracoda at Cheshmeh Boroun section, West of Qom

The aim of this study is determining systematics and identification of ostracods genera and species of the e Member of the Qom Formation at the studied section (Cheshmeh Boroun) for biostratigraphy and age determination, and palaeoecological investigations considering the abundance and diversity changes of ostracods based on the collected data.
The abundance and diversity of the ostracods taxa such as Paracypris¡ Aurila ¡Ruggieria ¡Loxochoncha ¡ Krithe¡ Xestoleberis, Cytherella mostly suggest a marine environment with normal salinity and warm climate from ecological point of view. However, the increase and decrease of these taxa in the studied section indicate the diversity and abundance changes is related to environmental changes. In fact, this shows the instability of the environmental conditions which seems to be affected by the changes of food and oxygen values, and water turbulence. Based on ostracods assemblages, an Early Miocene age ( Aquitanian- Burdigalian) is exclusively suggested for the e Member of the Qom Formation at Cheshmeh Boroun stratigraphic section.