The East China Sea (ECS) seasonally receives a high organic input due to the terrestrial organic matter influx, which is controlled by the East Asian Summer Monsoon (EASM), and the increased productivity driven by upwelling of the subsurface Kuroshio Current (KC). Changes in benthic foraminiferal assemblage composition in combination with paleoceanographic proxy data (CaCO3 (%), TOC (%), δ13Cpf, and δ18Obf) are used to reconstruct bottom water oxygenation and organic export flux variability over the last 400 kyr in the ECS. Multivariate analyses of benthic foraminiferal census data identified six biofacies characteristic of varying environmental conditions. These results suggest that enhanced EASM precipitation and KC upwelling directly influenced organic export flux and bottom water oxygen content in the ECS. The ECS bottom water was suboxic during Marine Isotope Stage (MIS) 11 to 8; suboxic to dysoxic between MIS 7 and 6, strongly dysoxic between mid-MIS 5 and 4, and exhibited high variability between MIS 3 and 1. Spectral analysis of relative abundances of representative genera Quinqueloculina (oxic), Bulimina (suboxic), and Globobulimina (dysoxic) reveals a robust 23 kyr signal, which we attribute to precessionally-paced changes in surface productivity and bottom water oxygenation related to EASM and KC variability over the past 400 kyr.

In 2015, Integrated Ocean Discovery Program Expedition 356 drilled along the margin off Western Australian to investigate the history of the Indonesian Throughflow (ITF) and its integral role in the development of global thermohaline circulation and climate. Throughout the expedition, a suite of foraminiferal analyses were employed wherein planktic specimens provided biostratigraphy and an incredibly diverse benthic fauna (~ 260 species) was used to reveal palaeo- water depth, palaeobathymetric setting and variable conditions at the sediment-water interface. Benthic foraminiferal biofacies are particularly sensitive to changes in environmental conditions, have a rapid turnover and are ideal proxies for monitoring physical and chemical changes in marine environments. When this information is combined with lithostratigraphic and other microfossil data, a robust understanding of past environments and past geological events can be reconstructed. Shipboard data were used to isolate horizons of interest for more intense sampling at IODP Site U1461, situated on the North-West Shelf, at 127 m of water depth. The shipboard data revealed a large (~150 m-thick) turbidite horizon hosting benthic foraminifera from a substantially shallower water depth than the horizon immediately preceding the horizon. We present preliminary foraminiferal results combined with shipboard sedimentary descriptions to better constrain the deposit’s occurrence in the biostratigraphic record, use benthic foraminifera to elucidate the deposit’s sedimentary origins and link this event with others in the region to investigate potential catalysts for its deposition.

To assess zonal temperature and biogeographical patterns in the Paleogene of the Southern Ocean, we present new multi-proxy air and sea surface temperature data for the latest Paleocene (~57–56 Ma) and the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma) from the northern margin of the Australo-Antarctic Gulf (AAG). The various proxies document the well-known late Paleocene gradual warming and, superimposed, two late Paleocene pre-cursor warming events, hundreds of kyrs prior to the PETM. Remarkably, however, air and sea surface temperature reconstructions for the AAG and SW Pacific during the latest Paleocene, PETM and Early Eocene Climatic Optimum (~53–49 Ma) show similar trends and, within proxies, similar absolute temperatures. The record implies that the exceptional warmth previously recorded in the SW Pacific extended westward into the AAG. This contrasts with the modeled circulation and temperature patterns. We suggest that simulations of ocean circulation underestimate heat transport in the SW Pacific due insufficient resolution, not allowing for mesoscale eddy-related heat transport. We argue for a systematic approach to tackle model and proxy biases in marginal marine settings, including assessment of underexplored factors as high-latitude proxy mechanisms to confidently assess temperature in these non-analogue climates.

Accurate dating of marine sediments is essential to reconstruct past changes in oceanography and climate. Benthic foraminiferal oxygen isotope series from such sediments record long-term changes in global ice volume and deep-water temperature. They are commonly used in the Plio-Pleistocene to correlate deep ocean records and to construct age models. However, continental margin settings often display much higher sedimentation rates due to variations in regional depositional setting and local input of sediment. Here, it is necessary to create a regional multi-site framework to allow precise dating of strata. We create such a high-resolution regional framework to determine the ages of events for the Northwest Shelf (NWS) of Australia, which was cored by International Ocean Discovery Program (IODP) Expedition 356. We employ benthic foraminiferal oxygen and carbon isotopes to construct an astronomically-tuned age model for IODP Site U1463. The age model is applied to the IODP Site U1463 downhole-logging natural gamma radiation (NGR) depth-series, which was then correlated to the NGR of other IODP sites and several industry wells in the area. The IODP Site U1463 age-depth model provides geologic time anchors for numerous sedimentary archives on the NWS. This approach allows assigning ages to regional seismic reflectors and the timing of key climate-related siliciclastic phases in a predominantly carbonate-rich sequence like the Bare Formation. Finally, this age model is used to chronologically calibrate planktonic foraminiferal biostratigraphic datums showing that the Indonesian Throughflow had shoaled enough during the early Pliocene to act as biogeographical barrier between the Pacific and Indian Ocean.