low Pacific reconstructed Liu & Herbert2004

Core/Site name:

ODP-138-846

Elevation:

-3295.8

Archive:

marine sediments (downcore)

Proxy measurement:

SST alkenones

Sampling resolution:

millennial

Startyear:

1833.700 ka BP

Endyear:

4.000 ka BP

Description:

Many records of tropical sea surface temperature and marine productivity exhibit cycles of 23 kyr (orbital precession) and 100 kyr during the past 0.5Myr, whereas high-latitude sea surface temperature records display much more pronounced obliquity cycles at a period of about 41 kyr. Little is known, however, about tropical climate variability before the mid-Pleistocene transition about 900 kyr ago, which marks the change from a climate dominated by 41-kyr cycles (when ice-age cycles and high-latitude sea surface temperature variations were dictated by changes in the Earth?s obliquity) to the more recent 100-kyr cycles of ice ages. Here we analyse alkenones from marine sediments in the eastern equatorial Pacific Ocean to reconstruct sea surface temperatures and marine productivity over the past 1.8Myr. We find that both records are dominated by the 41-kyr obliquity cycles between 1.8 and 1.2Myr ago, with a relatively small contribution from orbital precession, and that early Pleistocene sea surface temperatures varied in the opposite sense to local annual insolation in the eastern equatorial Pacific Ocean. We conclude that during the early Pleistocene epoch, climate variability at our study site must have been determined by high-latitude processes that were driven by orbital obliquity forcing.

Data entered by name:

Martrat, Belen

Data entered by email:

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Main reference(s):

Liu, Z. & Herbert, T. D. High-latitude influence on the eastern equatorial Pacific climate in the early Pleistocene epoch. Nature 427, 720-723, doi:http://www.nature.com/nature/journal/v427/n6976/suppinfo/nature02338_S1.html (2004).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/v427/n6976/abs/nature02338.html

Link to reference 2:

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

Data storage link 1:

https://www.ncdc.noaa.gov/paleo-search/study/6231

Comments:

woa09t_an0: 23.316999 ºC

Current dating method:

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Annual snow acc rate:

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Category: PIGS