Progressive shoaling of the equatorial Pacific thermocline over the last eight glacial periods
| Type | Article | ||||||||||||||||||||||||||||||||
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| Date | 2015-05 | ||||||||||||||||||||||||||||||||
| Language | English | ||||||||||||||||||||||||||||||||
| Author(s) | Regoli Fabienne1, de Garidel-Thoron Thibault1, Tachikawa Kazuyo1, Jian Zhiming2, Ye Liming3, Droxler Andre W.4, Lenoir Guillaume5, Crucifix Michel5, Barbarin Nicolas1, Beaufort Luc1 | ||||||||||||||||||||||||||||||||
| Affiliation(s) | 1 : Aix Marseille Univ, CNRS, CEREGE, UM34, Aix En Provence, France. 2 : Tongji Univ, Lab Marine Geol, Shanghai 200092, Peoples R China. 3 : Second Inst Oceanog, Hangzhou, Zhejiang, Peoples R China. 4 : Rice Univ, Houston, TX USA. 5 : Catholic Univ Louvain, Georges Lemaitre Ctr Earth & Climate Res, Louvain, Belgium. |
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| Source | Paleoceanography (0883-8305) (Amer Geophysical Union), 2015-05 , Vol. 30 , N. 5 , P. 439-455 | ||||||||||||||||||||||||||||||||
| DOI | 10.1002/2014PA002696 | ||||||||||||||||||||||||||||||||
| WOS© Times Cited | 24 | ||||||||||||||||||||||||||||||||
| Keyword(s) | equatorial Pacific, thermocline, Pleistocene | ||||||||||||||||||||||||||||||||
| Abstract | The depth of equatorial Pacific thermocline is diagnostic of the main modes of tropical climates. Past estimates of Pacific thermocline dynamics have been reconstructed either for the Last Glacial Maximum or on longer timescales at low resolution. Here we document a new high-resolution set of reconstructed past sea surface and subsurface waters temperatures from the southwestern subequatorial Pacific, core MD05-2930, in the Gulf of Papua, over the last 800 ka. We used two morphotypes of Globigerinoides ruber known to live at different water depths to reconstruct past stratification. We estimated calcification temperature of each morphotypes by Mg/Ca paleothermometry. Our subequatorial Pacific thermocline paleotemperature record indicates a response of the thermocline to both direct orbital forcing and glacial-interglacial changes. Our stratification record shows a systematic shallower glacial thermocline, whereas sea surface temperatures are characterized by precessional forcing. The record is indicative of a progressive long-term shoaling of the thermocline during the glacial stages during the late Pleistocene. The shoaling of the subequatorial Pacific thermocline is consistent with regional estimates. An enhanced South Pacific shallow overturning wind-driven circulation could have driven this progressive shoaling. We speculate that this late Pleistocene glacial shoaling of the thermocline could be related to an increase in the amplitude of the obliquity. | ||||||||||||||||||||||||||||||||
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