Journal ArticleDOI
Deepwater source variations during the last climatic cycle and their impact on the global deepwater circulation
J.-C. Duplessy,N.J. Shackleton,Richard G. Fairbanks,Laurent Labeyrie,Delia W Oppo,Nejib Kallel +5 more
TLDR
In this paper, a detailed reconstruction of the geographic distribution of ∂13C in benthic foraminifera in the Atlantic Ocean during the last glacial maximum was presented.Abstract:
The degree of similarity of the ∂13C records of the planktonic foraminiferal species N. pachyderma and of the benthic foraminiferal genus Cibicides in the high-latitude basins of the world ocean is used as an indicator of the presence of deepwater sources during the last climatic cycle. Whereas continuous formation of deep water is recognized in the southern ocean, the Norwegian Sea stopped acting as a sink for surface water during isotope stage 4 and the remainder of the last glaciation. However, deep water formed in the north Atlantic south of the Norwegian Sea during the last climatic cycle as early as isotope substage 5d, and this area was also the only active northern source during stages 4–2. A detailed reconstruction of the geographic distribution of ∂13C in benthic foraminifera in the Atlantic Ocean during the last glacial maximum shows that the most important deepwater mass originated from the southern ocean, whereas the Glacial North Atlantic Deep Water cannot be traced south of 40°N. At shallower depth an oxygenated 13C rich Intermediate Water mass extended from 45°N to 15°S. In the Pacific Ocean a ventilation higher than the modern one was also found in open ocean in the depth range 700–2600 m and is best explained by stronger formation of Intermediate Water in high northern latitudes.read more
Citations
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Journal ArticleDOI
How fast did the ocean—atmosphere system run during the last deglaciation?
Jean-Claude Duplessy,Edouard Bard,Maurice Arnold,N.J. Shackleton,Josette Duprat,Laurent Labeyrie +5 more
TL;DR: Oxygen isotope analyses performed on planktonic and benthic foraminifera in four deep sea cores show that during the last deglaciation, the meltwater isotopic signal propagated almost instantaneously in the whole North Atlantic and in less than one millennia in the Pacific and Indian deep waters as discussed by the authors.
Journal ArticleDOI
Depth profiles of δ13C in bottom water and core top C. wuellerstorfi on the Ontong Java Plateau and Emperor Seamounts
TL;DR: In this article, the carbon isotopic composition of dissolved inorganic carbon in bottom waters of the Ontong Java Plateau (western equatorial Pacific) and on the northern Emperor Seamounts (northwest Pacific) was measured.
Journal ArticleDOI
Increased upwelling off Portugal during the last glaciation: Diatom evidence
TL;DR: The diatom assemblage composition and preservation in two latest Quarternary (⋍ 100 ka to P.D.) cores from the continental slope of Portugal were studied in this article.
Journal ArticleDOI
Evidence for northward expansion of Antarctic Bottom Water mass in the Southern Ocean during the last glacial inception
Aline Govin,Aline Govin,Elisabeth Michel,Laurent Labeyrie,Claire Waelbroeck,Fabien Dewilde,Eystein Jansen +6 more
TL;DR: In this paper, the authors investigated deep water changes in the Southern Ocean during the last glacial inception, in relationship to surface hydrology and global climatology, to better understand the mechanisms of the establishment of a glacial ocean circulation.
Journal ArticleDOI
Geochemical evidence for anoxic deep water in the arabian sea during the last glaciation
TL;DR: In this article, the authors report geochemical evidence of near anoxic conditions in the deep Arabian Sea during the entire last glacial cycle (approximately 18 kyr B.P., stages 2, 3, and 4).
References
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Journal ArticleDOI
Smoothing and Differentiation of Data by Simplified Least Squares Procedures.
Journal ArticleDOI
The distribution of 13C of ΣCO2 in the world oceans
TL;DR: In this article, the results from 2252 samples from 107 hydrographic stations are presented as north-south vertical (depth) sections with δ13C contoured at intervals of 0.5−0.0075·AOU.
Journal ArticleDOI
North Atlantic thermohaline circulation during the past 20,000 years linked to high-latitude surface temperature
Edward A. Boyle,Lloyd D Keigwin +1 more
TL;DR: In this paper, the authors show that during a surface cooling event 10,000 to 12,000 years ago, higher Cd/Ca and lower 13C/12C ratios are observed in benthic foraminifera shells from rapidly accumulating western North Atlantic sediments.
Journal ArticleDOI
Comparison of Atlantic and Pacific paleochemical records for the last 215,000 years : changes in deep ocean circulation and chemical inventories
Edward A. Boyle,Lloyd D Keigwin +1 more
TL;DR: In this article, detailed Cd/Ca and δ 13 C data have been obtained for benthic foraminifera from western North Atlantic and Equatorial Pacific sediment cores, which indicate that bottom waters overlying the Atlantic site have been nutrient depleted relative to those at the Pacific site over the last 215,000 years.
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North Atlantic thermohaline circulation during the past 20,000 years linked to high-latitude surface temperature
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