Large obliquity-paced Antarctic ice-volume fluctuations suggest melting by atmospheric and ocean warming during late Oligocene
Abstract The late Oligocene (~27.8–23 My ago) offers an opportunity to study past climate variability under high-CO2, warmer-than-present and the unipolar (Antarctic) glaciated state. Here, we present new high-resolution geochemical records from exquisitely well-preserved benthic foraminifera for th...
| Published in: | Communications Earth & Environment |
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| Main Authors: | , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Nature Portfolio
2023
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| Subjects: | |
| Online Access: | https://doi.org/10.1038/s43247-023-00864-9 https://doaj.org/article/60dfa206473244329c3cc58abccb0a76 |
| Summary: | Abstract The late Oligocene (~27.8–23 My ago) offers an opportunity to study past climate variability under high-CO2, warmer-than-present and the unipolar (Antarctic) glaciated state. Here, we present new high-resolution geochemical records from exquisitely well-preserved benthic foraminifera for the late Oligocene, an interval for which Antarctic ice-sheet size and stability are debated. Our records indicate four obliquity-paced glacial-interglacial cycles with ice-volume changes of up to ~70% of the modern Antarctic ice-sheet. The amplitude of ice-volume change during these late Oligocene glacial-interglacial cycles is comparable to that of the late Pliocene and early Pleistocene. Ice-volume estimates for interglacials are small enough to be accommodated by a land-based Antarctic ice-sheet but, for three of the four glacials studied, our calculations imply that ice sheets likely advanced beyond the Antarctic coastline onto the shelves. Our findings suggest an Antarctic ice-sheet vulnerable to melting driven by both bottom-up (ocean) and top-down (atmospheric) warming under late Oligocene warmer-than-present climate conditions. |
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