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| Liu, Wei; Baudin, Francois; Moreno, Eva; Dewilde, Fabien; Caillon, Nicolas; Fang, Nianqiao; Bassinot, Franck. |
| Total organic carbon (TOC) and calcium carbonate (CaCO3) records from different water depths in the Timor Sea (NE Indian Ocean) are compared in order to better reconstruct past changes in pelagic productivity, highlight the impact of preservation at depth, and unravel the interplay of organic carbon and carbonate sedimentation. New data are presented for core MD01-2376 located at 2376 m depth. These results are compared, over the last 240 ka, with published data on two neighboring cores (MD01-2378, 1783 m and MD98-2166, 3875 m). TOC fluctuations show strong glacial/interglacial variations and Milankovitch-type oscillations (i.e., dominant frequencies centered on the 100, 41, and 23 ka bands), with an enrichment during cold periods that reflects an increase... |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40149/39258.pdf |
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| Levi, Camille; Labeyrie, Laurent; Bassinot, Franck; Guichard, Francois; Cortijo, Elsa; Waelbroeck, Claire; Caillon, Nicolas; Duprat, Josette; De Garidel-thoron, Thibault; Elderfield, Harry. |
| Sea surface temperature and oxygen isotopic records from two well-dated Indian Ocean cores covering the last deglaciation show the occurrence of two periods of increased salinity along the route of warm surface water transport from the Indian to the Atlantic Ocean, one between 18 and 14.5 ka and the other during the Younger Dryas. Our results imply that during these periods, salt accumulated in the tropical Atlantic, creating favorable conditions for an abrupt resumption of the thermohaline circulation and abrupt northern hemisphere warming. Furthermore, we suggest that the observed pattern of millennial climate variability during the last glacial and deglaciation resulted from the interaction between the relatively slow rhythm of expansion and decay of... |
| Tipo: Text |
Palavras-chave: Rapid climate changes; Low-latitude hydrological cycle; Last deglaciation. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34611/32960.pdf |
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| Cleroux, Caroline; Cortijo, Elsa; Anand, Pallavi; Labeyrie, Laurent; Bassinot, Franck; Caillon, Nicolas; Duplessy, Jean-claude. |
| [1] Reliable temperature estimates from both surface and subsurface ocean waters are needed to reconstruct past upper water column temperature gradients and past oceanic heat content. This work examines the relationships between trace element ratios in fossil shells and seawater temperature for surface-dwelling foraminifera species, Globigerinoides ruber (white) and Globigerina bulloides, and deep-dwelling species, Globorotalia inflata, Globorotalia truncatulinoides (dextral and sinistral) and Pulleniatina obliquiloculata. Mg/Ca and Sr/Ca ratios in shells picked in 29 modern core tops from the North Atlantic Ocean are calibrated using calculated isotopic temperatures. Mg/Ca ratios on G. ruber and G. bulloides agree with published data and relationships.... |
| Tipo: Text |
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| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00237/34806/33325.pdf |
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| Riveiros, Natalia Vazquez; Govin, Aline; Waelbroeck, Claire; Mackensen, Andreas; Michel, Elisabeth; Moreira, Santiago; Bouinot, Thomas; Caillon, Nicolas; Orgun, Ayche; Brandon, Margaux. |
| Planktic foraminiferal Mg/Ca ratios have become a fundamental seawater temperature proxy in past climate reconstructions, due to the temperature dependence of Mg uptake into foraminiferal calcite. However, empirical calibrations for single species from methodologically consistent data are still lacking. Here we present species-specific calibrations of Mg/Ca versus calcification temperature for two commonly used species of planktic foraminifera: Globigerina bulloides and Neogloboquadrina pachyderma left, based on a series of Southern Ocean and North Atlantic core tops. Combining these new data with previously published data, we derive an integrated G. bulloides Mg/Ca-temperature calibration for mid and high latitudes of both hemispheres between 2 and 18°C,... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00324/43480/42916.pdf |
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| Boussetta, Soumaya; Kallel, Nejib; Bassinot, Franck; Labeyrie, Laurent; Duplessy, Jean-claude; Caillon, Nicolas; Dewilde, Fabien; Rebaubier, Helene. |
| We generated a high-resolution SSTMg/Ca record for the surface-dwelling planktonic foraminifera Globigerina bulloides from the core MD99-2346 collected in the Gulf of Lion, and compared it to that obtained using modern analogue techniques applied to fossil foraminiferal assemblages (SSTMAT). The two temperature records display similar patterns during the last 28,000 years but the SSTMg/Ca estimates are several degrees warmer (similar to+4 degrees C) than SSTMAT. The temperature shift between SSTMg/Ca and SSTMAT remained relatively constant over time. This seems to exclude a bias on the Mg/Ca record associated with salinity or secondary Mg-rich calcite encrustation on the foraminiferal tests during early diagenesis. Therefore, anomalously high Mg/Ca... |
| Tipo: Text |
Palavras-chave: Mediterranean; Mg/Ca; Planktonic foraminifera; Sea surface Temperature; Salinity; Diagenesis; Vital effect. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00139/25047/23181.pdf |
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