Paleoceanographic changes in the Eastern Equatorial Pacific over the last 10 Myr

Seki, Osamu; Schmidt, Daniela N.; Schouten, Stefan; Hopmans, Ellen C.; Damsté, Jaap S. Sinninghe; Pancost, Richard D.

Paleoceanographic changes in the Eastern Equatorial Pacific over the last 10 Myr

Seki, Osamu; Schmidt, Daniela N.; Schouten, Stefan et al.

Paleoceanography, 2012, 27(3), PA3224

Permalink : https://hdl.handle.net/2115/52111

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アクセス権	open access
URI	https://hdl.handle.net/2115/52111
タイトル	Paleoceanographic changes in the Eastern Equatorial Pacific over the last 10 Myr
著者	Seki, Osamu ; Schmidt, Daniela N. ; Schouten, Stefan ; Hopmans, Ellen C. ; Damsté, Jaap S. Sinninghe ; Pancost, Richard D.
e-Rad_Researcher 30374648 著者名 Seki, Osamu
著者名 Schmidt, Daniela N.
著者名 Schouten, Stefan
著者名 Hopmans, Ellen C.
著者名 Damsté, Jaap S. Sinninghe
著者名 Pancost, Richard D.
言語	英語
キーワード	TEX86
	Tropical Pacific
	alkenone
	diol index
発行日	2012-09-01
出版者	American Geophysical Union
収録物名	Paleoceanography
巻(号)	27(3)
ページ	PA3224
抄録	To examine the Late Neogene evolution of tropical Pacific oceanography, we determined multiple geochemical proxy records for temperature (U37^[K'] and TEX86^[H] indices) and primary productivity (algal biomarkers and diol indices) in sediments recovered at ODP Site 1241 in the East Equatorial Pacific (EEP) spanning a record of the last 10 Myr. The TEX86^[H] temperatures are lower than those recorded by U37^[K'] indices, exhibiting large fluctuations and suggesting strong warming during the Mid Pliocene Warm Period (MPWP; 4.5-3.2 Ma) and significantly colder temperature during the Late Miocene cooling period (7-5 Ma) and after the Middle Pliocene Warm Period (MPWP). Such variations could reflect changes in the EEP thermocline temperatures, but we suggest that they instead reflect changes in the depth of export production of glycerol dialkyl glycerol tetraether lipids in response to changes in the upper ocean structure. A combination of temperature records, inferred to represent different and likely varying depths in the water column, as well as algal biomarker records for export production and ecosystem structure, suggest that both productivity and inference upwelling were reduced in the EEP during warmer periods, such as the MPWP and prior to 7 Ma. In contrast, stronger upwelling conditions and associated increased productivity likely prevailed from 7 to 5 Ma and for the past 3 Myr, both corresponding to globally cool intervals. A further increase in EEP productivity occurred at ca 1.8 Ma, coincident with the development of the E-W Pacific SST gradient. These results confirm previous work that protracted El Niño-like conditions prevailed during warmer intervals of the Pliocene before ultimately descending into the current climate state.
資源タイプ	学術雑誌論文
出版タイプ	Version of Record
権利情報	©2012 American Geophysical Union
PISSN	0883-8305
関連情報 (isIdenticalTo)	出版社版DOI https://doi.org/10.1029/2011PA002158