oa Sea Level Changes and Depositional Environments of the Late Cretaceous to Paleocene Sedimentary Succession, Izeh, Zagros Basin, Iran

Integration of micro-biostratigraphy and palynofacies analysis of the Gurpi Formation at the Danial<br>section, northeast Izeh, Zagros basin, Iran, provide improved age resolution and information on the<br>reconstruction of depositional environments. The section is a key succession to investigate the late<br>Cretaceous to Paleocene sea level history. Relatively deep marine dark bluish gray calcareous shale,<br>marl and argillaceous lime mudstone of the Gurpi Formation, which marks the late Cretaceous -<br>Paleocene sequence exposed the interval between the Ilam Formation of Santonian age and the<br>overlying Pabdeh Formation of late Paleocene-Oligocene age. The age of the Gurpi Formation in the<br>section is estimated to span from late Campanian (Radotruncana calcarata planktonic foraminifera<br>biozone) to late Paleocene (Globanomalina pseudomenardii planktonic foraminifera zone). The K/T<br>boundary within the upper part of the formation marks continuously by using the zones CF1 (P.<br>hantkeninoides; Latest Maastrichtiaqn, 65.3-65Ma) and P0-P (P. eugubina-G. cretacea; base of Danian<br>age, 65-64.97Ma) respectively.<br>Results from a sea-level change analysis, based on palynofacies analysis and additional proxies<br>(percent planktic foraminifera, planktic foraminifera morphogroups, total organic carbon content<br>(TOC), and geophysical GR log) show a general deepening trend for the investigated sections. As a<br>result, the sedimentary succession reflects deposition in outer neritic environment and no any tectonic<br>activities during the Maastrichtian-Paleocene in the basin but more rapid sea-level changes, consistent<br>with increasing ice volume during the time interval in the world. The area was located near the<br>palaeoequator and provides tropical to subtropical paleoenvironmental conditions. Finally, six Type-III<br>sequences was distinguished in the section during the study. Microfacieous analysis of the marls and<br>argillaceous lime mudstones (Emam Hassan Member) at the middle part of the sediment succession<br>provides three main microfacies corresponds to two , tree, and four facies belts of Flugle, 2004 that<br>show relatively deep marine environment at the end of continental slope during sea-level highstand in<br>outer to inner neritic environments. On the other hand, fossiliferous marly shales and marls at the<br>lower and upper parts of the succession during sea-level rising characterized by dysaerobic or low<br>oxygen conditions in outer neritic environments.