Nairn, Michael G., Lear, Caroline H.  ORCID: https://orcid.org/0000-0002-7533-4430, Sosdian, Sindia M. ORCID: https://orcid.org/0000-0002-4599-5529, Bailey, Trevor R. and Beavington-Penney, Simon
2021.
Tropical sea surface temperatures following the middle Miocene climate transition from laser-ablation ICP-MS analysis of glassy foraminifera.
Paleoceanography and Paleoclimatology
36
(3)
, e2020PA004165.
10.1029/2020PA004165
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Abstract
The unipolar icehouse world of the mid-late Miocene is a poorly understood interval in the evolution of Cenozoic climate, and the sparse proxy-based climate reconstructions are associated with large uncertainties. In particular, tropical sea surface temperature (SST) estimates largely rely on the unsaturated alkenone U proxy, which fails to record temperatures higher than 29˚C, and Mg/Ca ratios of poorly preserved foraminifera. We reconstruct robust, absolute, SSTs between 13.5 Ma and 9.5 Ma from the South West Indian Ocean (paleolatitude ~5.5˚S) using Laser-Ablation (LA-) ICP-MS microanalysis of glassy planktic foraminiferal Mg/Ca. Employing this microanalytical technique, and stringent screening criteria, permits the reconstruction of robust paleotemperatures from Mg/Ca thermometry using foraminifera which although glassy, are contaminated by authigenic coatings. Our absolute estimates of 24-31⁰C suggest that SST in the tropical Indian Ocean was relatively constant between 13.5 and 9.5 Ma, similar to those reconstructed from the tropics using the U alkenone proxy. This suggests an interval of enhanced polar amplification between 10 and 7.5 Ma, immediately prior to the global late Miocene Cooling. The mid-to-late Miocene is proposed as a key interval in the transition of the Earth’s climate state towards that of the modern-day.
| Item Type: | Article |
|---|---|
| Date Type: | Publication |
| Status: | Published |
| Schools: | Schools > Earth and Environmental Sciences |
| Additional Information: | This is an open access article under the terms of the Creative Commons Attribution License |
| Publisher: | American Geophysical Union |
| ISSN: | 2572-4525 |
| Funders: | NERC |
| Date of First Compliant Deposit: | 3 February 2021 |
| Date of Acceptance: | 1 February 2021 |
| Last Modified: | 16 May 2023 23:01 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/138227 |
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