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| Hoogakker, Babette A. A.; Chapman, Mark R.; Mccave, I. Nick; Hillaire-marcel, Claude; Ellison, Christopher R. W.; Hall, Ian R.; Telford, Richard J.. |
| High resolution flow speed reconstructions of two core sites located on Gardar Drift in the northeast Atlantic Basin and Orphan Knoll in the northwest Atlantic Basin reveal a long-term decrease in flow speed of Northeast Atlantic Deep Water (NEADW) after 6,500 years. Benthic foraminiferal oxygen isotopes of sites currently bathed in NEADW show a 0.2 parts per thousand depletion after 6,500 years, shortly after the start of the development of a carbon isotope gradient between NEADW and Norwegian Sea Deep Water. We consider these changes in near-bottom flow vigor and benthic foraminiferal isotope records to mark a significant reorganization of the Holocene deep ocean circulation, and attribute the changes to a weakening of NEADW flow during the mid to late... |
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| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33787/32562.pdf |
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| Thibodeau, Benoit; De Vernal, Anne; Hillaire-marcel, Claude; Mucci, Alfonso. |
| The impact of human activities on Earth's climate is still subject to debate and the pattern of a sharp recent global temperature increase contrasting with much lesser variable temperatures during preceding centuries has often been challenged, partly due to the lack of unquestionable evidence. In this paper, oxygen isotope compositions of benthic foraminifer shells recovered from sediments of the Lower St. Lawrence Estuary and the Gulf are used to reconstruct temperature changes in a water mass originating from similar to 400 m deep North Atlantic waters. The data demonstrate that the 1.7 +/- 0.3 degrees C warming measured during the last century corresponds to a delta(18)O shift of 0.4 +/- 0.05 parts per thousand, encompassing the temperature effect and... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34176/32910.pdf |
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| Maccali, Jenny; Hillaire-marcel, Claude; Ghaleb, Bassam; Ménabréaz, Lucie; Blénet, Aurélien; Edinger, Evan; Hélie, Jean-françois; Preda, Michel. |
| About 70 fossil and live-collected specimens of Desmophyllum dianthus were collected from steep rocky surfaces and time-averaged assemblages at their base (“coral graveyards”) in the southern Labrador Sea at depths ranging from ~1700 m (Orphan Knoll) to ~2200 m (Flemish Cap). Aside from stable isotope and mineralogical analysis, U-series and 14C age determinations were performed on the samples. Fossil corals from the coral graveyards display two principal age clusters corresponding respectively to the Holocene and Marine Isotope Stage (MIS) 5c intervals. Three samples lay outside these clusters, at ~13.5 ka (Bølling-Allerød), ~ 64 ka (MIS 3) and at ~181 ka (MIS 7a). The clusters are thought to record intervals with both i) high food availability, either... |
| Tipo: Text |
Palavras-chave: Deep-sea corals; Aragonite corals; Labrador Sea; Radiocarbon; U-series dating. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00623/73496/72790.pdf |
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| Evans, Helen F.; Channell, James E. T.; Stoner, Joseph S.; Hillaire-marcel, Claude; Wright, James D.; Neitzke, Lauren C.; Mountain, Gregory S.. |
| Four piston cores collected in 1999 and 2002 from the Eirik Drift (southern Labrador Sea, off SE Greenland) provide paleomagnetic, environmental magnetic, and oxygen isotope records back to marine isotope stage 11. Age models for the cores are based on a combination of planktonic oxygen isotope data, relative geomagnetic paleointensity proxies, and the identification of geomagnetic excursions (Laschamp and Iceland Basin). Environmental magnetic data delineate two distinct detrital signals, interpreted to reflect the behavior of the surrounding ice sheets (Greenland and Laurentide) to orbital-and millennial-scale climate forcing. Broad decimeter-scale intervals of increased magnetic concentration and grain size occur during the early part of interglacial... |
| Tipo: Text |
Palavras-chave: Paleointensity. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34625/32978.pdf |
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