Benthic foraminiferal stable isotopes, planktonic foraminiferal biostratigraphy and seismic profiles for IODP Site 356-U1463

Determining the age of marine sediments is essential to reconstruct past changes in oceanography and climate. The oxygen isotopes of benthic foraminifera record long-term changes in global ice volume and deep-water temperature, and are commonly used to construct age models. However, continental margin settings often display much higher sedimentation rates due to regional input by rivers. Here, it is necessary to create a regional framework to allow precise dating of strata. We created such a framework for the Northwest Shelf (NWS) of Australia, which was cored by International Ocean Discovery Program (IODP) Expedition 356. We used oxygen and carbon isotopes in benthic foraminifera to construct an astronomically-tuned age model for IODP Site U1463. The natural gamma radiation (NGR) variations for IODP Site U1463 were then correlated to those of other IODP sites and industry wells in the area. The IODP Site U1463 age-depth model thus provides a reference for other archives on the NWS allowing to assign ages to regional seismic reflectors and the timing of sediment input via rivers. This age model is also used to determine first and last occurrences of foraminifera showing that the Indonesian Throughflow (ITF) blocked the migration of foraminifera from the Pacific to the Indian Ocean after 5 Ma.