A 12-million-year temperature history of the tropical Pacific Ocean
In: Science (Washington). American Association for the Advancement of Science: New York, N.Y. ISSN 0036-8075; e-ISSN 1095-9203, more
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| Authors | | Top |
- Zhang, Y.G.
- Pagani, M.
- Liu, Z.
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| Abstract |
The appearance of permanent El Nino-like conditions prior to 3 million years ago is founded on sea-surface temperature (SST) reconstructions that show invariant Pacific warm pool temperatures and negligible equatorial zonal temperature gradients. However, only a few SST records are available, and these are potentially compromised by changes in seawater chemistry, diagenesis, and calibration limitations. For this study, we establish new biomarker-SST records and show that the Pacific warm pool was similar to 4 degrees C warmer 12 million years ago. Both the warm pool and cold tongue slowly cooled toward modern conditions while maintaining a zonal temperature gradient of similar to 3 degrees C in the late Miocene, which increased during the Plio-Pleistocene. Our results contrast with previous temperature reconstructions that support the supposition of a permanent El Nino-like state. |
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