Evolution of the zonal gradients across the equatorial Pacific during the Miocene–Pleistocene

Catherine Beltran*, Gabrielle Rousselle, Marc de Rafélis, Marie Alexandrine Sicre, Nathalie Labourdette, Stefan Schouten

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Combining U k 37 0 - and TEX 86 -derived temperatures and oxygen isotopic values of mixed-layer and thermocline species from the IODP site U1338 (East Equatorial Pacific) and ODP Site 806 (West Equatorial Pacific) we assess the evolution of the zonal sea-surface temperature gradients and thermocline depth across the equatorial Pacific from the late Miocene through the Pleistocene. Data suggest a long-term shoaling of the thermocline along the equator throughout the Miocene–Pliocene that accelerated around 5.3 Ma. We identify a critical transition at about 3.8 Ma from a El-Niño-like-dominated mean state during the late Miocene and early Pliocene to a La-Niña-like-dominated state during the late Pliocene–Pleistocene. This transition coincides with the restriction of the Indonesian seaway and the onset of ice growth in the northern hemisphere and in Antarctica that led to the long-term strengthening of the Walker circulation and affected low-latitude zonal gradient.

Original languageEnglish
Pages (from-to)242-252
Number of pages11
JournalJournal of Sedimentary Research
Issue number3
Publication statusPublished - 25 Mar 2019


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