low Pacific reconstructed de Garidel-Thoron2005

Core/Site name:

MD97-2140

Elevation:

-2547

Archive:

marine sediments (downcore)

Proxy measurement:

SST MgCa

Sampling resolution:

millennial

Startyear:

1755 ka BP

Endyear:

6 ka BP

Description:

About 850,000 years ago, the period of the glacial cycles changed from 41,000 to 100,000 years. This mid-Pleistocene climate transition has been attributed to global cooling, possibly caused by a decrease in atmospheric carbon dioxide concentrations. However, evidence for such cooling is currently restricted to the cool upwelling regions in the eastern equatorial oceans, although the tropical warm pools on the western side of the ocean basins are particularly sensitive to changes in radiative forcing. Here we present high-resolution records of sea surface temperatures spanning the past 1.75 million years, obtained from oxygen isotopes and Mg/Ca ratios in planktonic foraminifera from the western Pacific warm pool. In contrast with the eastern equatorial regions, sea surface temperatures in the western Pacific warm pool are relatively stable throughout the Pleistocene epoch, implying little long-term change in the tropical net radiation budget. Our results challenge the hypothesis of a gradual decrease in atmospheric carbon dioxide concentrations as a dominant trigger of the longer glacial cycles since 850,000 years ago. Instead, we infer that the temperature contrast across the equatorial Pacific Ocean increased, which might have had a significant influence on the mid-Pleistocene climate transition.

Data entered by name:

Martrat, Belen

Data entered by email:

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Main reference(s):

de Garidel-Thoron, T., Rosenthal, Y., Bassinot, F. & Beaufort, L. Stable sea surface temperatures in the western Pacific warm pool over the past 1.75[thinsp]million years. Nature 433, 294-298, doi:http://www.nature.com/nature/journal/v433/n7023/suppinfo/nature03189_S1.html (2005).Lang, N. & Wolff, E. W. Interglacial and glacial variability from the last 800 ka in marine, ice and terrestrial archives. Clim. Past 7, 361-380, doi:10.5194/cp-7-361-2011 (2011).

Link to reference 1:

http://www.nature.com/nature/journal/v433/n7023/abs/nature03189.html

Link to reference 2:

http://www.clim-past.net/7/361/2011/

Data storage link 1:

https://www.ncdc.noaa.gov/paleo/study/2619

Data storage link 2:

http://www.clim-past.net/7/361/2011/

Comments:

woa09t_an0: 26.853001 ºC

Current dating method:

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Annual snow acc rate:

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Category: PIGS