A study on controlling depositional processes and their effects on distribution of organisms and trace fossils in offshore environments of the South Caspian Sea (Langroud-Roudsar Coasts)

The simultaneous study on sedimentology، fossil content and sedimentary structures on loose sediments of the offshore South Caspian Sea led to a better understanding of sedimentary environments and their role in distribution of organisms and trace fossils. In this paper، by studying the mentioned factors via core data، the environmental condition of recent environment has been analyzed. For the first time in Iran، the CT-Scan technique was used in sedimentology for reconstruction of sedimentary environments، based on the cores obtained from offshore environment from the Caspian Sea (Langroud-Roudsar coasts). The results from this study led to recognition of three sedimentary facies and one ichnofacies in sediments of Caspian Sea floor. These sediments show an alternation of high level energy condition (low density turbidity current) and quasi-steady conditions. The stated conditions led to a propagation of hemipelagic deposits with silty-mud interlayers. The results from this study indicate that depositional processes had a significant effect on environmental conditions، distribution of organisms and trace fossil abundance.