New findings from paleoecology of Upper Cretaceous in Tethys ocean(territory of Central Zagros)

In order to research paleoecological of rudists, the effects of environment and sedimentation conditions on their lives, were selected and studied three sections of Tarbur Formation including Tang-e Vanak, Tang-e Zendan and Kuh-e Dezdaran in Centeral of Zagros zone in Chaharmahal and Bakhtiyari province . The entry of detrital sediments of Amiran Formation into the basin in Tang-e-Vanak and Tang-e-Zandan sections has caused an increase in nutrients and created eutrophic conditions, This situation has caused the rudists to become huge in order to feed the rudists fauna, which have all been suspended.. If in the section of Dezdaran mountain, with the absence of deposits of the Amiran Formation, the body of the rudists is in a normal state. The Rudists of two families of Hippuritidae and Dictyoptychidea who lived alone in soft and muddy beds, had a very long and boot-shaped shape in two sections Tang Vanak and Tang Zendan it has a very long and boot-like shape due to loss of balance and dormancy and overturning of the oyster due to high length and weight at high energy, and on the other hand oyster regrowth after dormancy, to the vertical to avoid burial in detrital Amiran sediments have been. The oyster’s complexity has been a way to balance them in high-energy environments