4 High latitude paleoceanographic discoveries from Scientific Ocean Drilling (IODP, ODP, DSDP)

Scientific Ocean Drilling has retrieved thousands of meters of sediment cores from the high latitude oceans.  This session provides the opportunity to present the results of work to understand Cenozoic climate and oceanographic changes.

Sunday, 22 March 2026
8:00 AM - 12:00 PM
CCC, Room 27

Glacial-Interglacial Subantarctic to Polar Frontal Zone Dynamics in the Southeastern Indian Sector of the Southern Ocean

Paper number: 4-10
Program: Technical Sessions
Time: 11:00 AM – 11:20 AM

Authors

Abstract

There is a global scientific consensus that anthropogenically-forced warming will likely continue at a rate of 0.2°C per decade, with global temperature reaching 1.5°C above pre-industrial levels by the beginning of the next decade (IPCC, 2023). Such warming has implications for major ocean currents, as seen in the past under various climate forcings on geologic time scales. As such, deciphering regional surface water responses to warming is imperative to adding to the greater understanding of how the Earth system will respond to this magnitude of warming.

In this work we reconstruct the temperature and general productivity changes of Antarctic Circumpolar Current (ACC) fronts throughout MIS 1 to MIS 6 using a deep sea (3,442 m) sediment core from the southeast Indian Ocean sector of the Southern Ocean. The RC08-63PC sediment core was collected along a major frontal boundary of the ACC, associated with the Subantarctic Front (SAF). Positioned along the Southern Hemisphere mid-latitudes, the SAF represents the southernmost boundary of the Subantarctic Zone (SAZ) and the northernmost boundary of the Polar Frontal Zone (PFZ). These two areas are distinct in their seasonal mixed layer depth, nutrient content, salinity, and plankton assemblages.

A multi-proxy approach using geochemical and palaeo-ecological proxies are implemented. Planktic foraminiferal stable isotope (δ18O and δ13C) data from the thermocline dwelling species Globoconella inflata and mixed-layer species Globigerina bulloides were analyzed to determine changes in the thermal (δ18O ) and nutrient profiles (δ13C) of the surface water layer. In addition, planktic foraminiferal assemblage analysis, at a ~2,400-year resolution, are used to make qualitative inferences about surface water conditions. Further, high resolution x-ray fluorescence (XRF) ratios are compared to stable isotope and planktic foraminiferal data sets to further expound on frontal shift behavior during the most recent six glacial-interglacial cycles.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411112

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