Abstract
Large Oligocene Antarctic ice sheets co-existed with warm proximal waters offshore Wilkes Land. Here we provide a broader Southern Ocean perspective to such warmth by reconstructing the strength and variability of the Oligocene Australian-Antarctic latitudinal sea surface temperature gradient. Our Oligocene TEX86-based sea surface temperature record from offshore southern Australia shows temperate (20–29 °C) conditions throughout, despite northward tectonic drift. A persistent sea surface temperature gradient (~5–10 °C) exists between Australia and Antarctica, which increases during glacial intervals. The sea surface temperature gradient increases from ~26 Ma, due to Antarctic-proximal cooling. Meanwhile, benthic foraminiferal oxygen isotope decline indicates ice loss/deep-sea warming. These contrasting patterns are difficult to explain by greenhouse gas forcing alone. Timing of the sea surface temperature cooling coincides with deepening of Drake Passage and matches results of ocean model experiments that demonstrate that Drake Passage opening cools Antarctic proximal waters. We conclude that Drake Passage deepening cooled Antarctic coasts which enhanced thermal isolation of Antarctica.
| Original language | English |
|---|---|
| Article number | 322 |
| Pages (from-to) | 1-8 |
| Journal | Communications Earth and Environment |
| Volume | 3 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 22 Dec 2022 |
Bibliographical note
Funding Information:This work used archived samples and data provided and curated by the IODP and its predecessors. This work was financially supported by the NWO polar programme (ALW.2016.001). We thank José Guitián, Heather Stoll and Lena Thӧle for providing the subset of samples from ETH Zürich. We also thank Mariska Hoorweg for technical support and Suning Hou for additional discussion. IS and PB acknowledges funding through ERC starting grant 802835 “OceaNice”. MH acknowledges support from NSF OPP grant 1842059.
Funding Information:
This work used archived samples and data provided and curated by the IODP and its predecessors. This work was financially supported by the NWO polar programme (ALW.2016.001). We thank José Guitián, Heather Stoll and Lena Thӧle for providing the subset of samples from ETH Zürich. We also thank Mariska Hoorweg for technical support and Suning Hou for additional discussion. IS and PB acknowledges funding through ERC starting grant 802835 “OceaNice”. MH acknowledges support from NSF OPP grant 1842059.
Publisher Copyright:
© 2022, The Author(s).
Funding
This work used archived samples and data provided and curated by the IODP and its predecessors. This work was financially supported by the NWO polar programme (ALW.2016.001). We thank José Guitián, Heather Stoll and Lena Thӧle for providing the subset of samples from ETH Zürich. We also thank Mariska Hoorweg for technical support and Suning Hou for additional discussion. IS and PB acknowledges funding through ERC starting grant 802835 “OceaNice”. MH acknowledges support from NSF OPP grant 1842059. This work used archived samples and data provided and curated by the IODP and its predecessors. This work was financially supported by the NWO polar programme (ALW.2016.001). We thank José Guitián, Heather Stoll and Lena Thӧle for providing the subset of samples from ETH Zürich. We also thank Mariska Hoorweg for technical support and Suning Hou for additional discussion. IS and PB acknowledges funding through ERC starting grant 802835 “OceaNice”. MH acknowledges support from NSF OPP grant 1842059.