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| Grousset, Fe; Cortijo, E; Huon, S; Herve, L; Richter, T; Burdloff, D; Duprat, J; Weber, O. |
| Theories explaining the origin of the abrupt, massive discharges of ice-rafted detritus (IRD) into the glacial North Atlantic (the Heinrich layers (HLs)) generally point to the Laurentide ice sheet as the sole source of these events, until it was found that the IRDs also originated from Icelandic and European ice sheets [Bond and Lotti, 1995; Snoeckx er al., 1999; Grousset et al., 2000]. This apparent contradiction must be reconciled as it raises fundamental questions about the mechanism(s) of HL origin. We have analyzed two similar to 12 cm thick HLs in an ultrahigh-resolution mode (1-2 century intervals) in a mid-Atlantic ridge piston core. The delta O-18 record (N. pachyderma left coiling) reveals strong excursions induced by the melting of the... |
| Tipo: Text |
Palavras-chave: Climate and interannual variability; Climate dynamics; Radiogenic isotope geochemistry. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/00221/33190/31786.pdf |
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| Duplessy, Jc; Labeyrie, L; Juilletleclerc, A; Maitre, F; Duprat, J; Sarnthein, M. |
| We have developed a new method to reconstruct surface water salinity of the North Atlantic Ocean, based on a comparison between transfer function estimates of sea surface temperature and the oxygen isotope ratio of two common planktonic foraminiferal species, N. pachyderma (left coiling) and G. bulloides. We first used core-top analyses to demonstrate that, under modern conditions, the paleotemperatures determined from the isotopic composition of foraminiferal shells are linearly linked to the summer sea surface temperature only within a certain temperature range, characteristic of each species, which is termed the "optimum temperature range". We then used this information to derive an estimate of the isotopic composition and salinity of the North Atlantic... |
| Tipo: Text |
Palavras-chave: PALEO-OCEANOGRAPHY; PALEOCLIMATOLOGY; ISOTOPES; SALINITY; ATLANTIC OCEAN. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00101/21261/18872.pdf |
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| Gayet, J; Carbonel, P; Duprat, J; Labeyrie, L; Faugeres, J-c; Gonthier, E; Moyes, J. |
| Biomarker data associated with isotopic curve partial differential super(18)O served to establish a stratigraphic scale and thereby a chronology of fluctuations in the circulation and sedimentation of the Kalimantan continental rise throughout the last climatic cycle. During the glacial maximum, period of low sea-level sediments were deposited by turbidity currents originating from Kalimantan. During deglaciation, during rise of the sea-level and more particularly in the Holocene, material issued from Kalimantan either contributed to the building of the Mahakam delta or was dispersed over the shelf. Sulawesi inputs, less abundant and mineralogically different from Kalimantan material, were observed onto the Kalimantan rise. During this same period,... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37898/35979.pdf |
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