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| Marzin, C.; Kallel, Nejib; Kageyama, Masa; Duplessy, Jean-claude; Braconnot, Jean-claude. |
| Several paleoclimate records such as from Chinese loess, speleothems or upwelling indicators in marine sediments present large variations of the Asian monsoon system during the last glaciation. Here, we present a new record from the northern Andaman Sea (core MD77-176) which shows the variations of the hydrological cycle of the Bay of Bengal. The high-resolution record of surface water delta O-18 dominantly reflects salinity changes and displays large millennial-scale oscillations over the period 40 000 to 11 000 yr BP. Their timing and sequence suggests that events of high (resp. low) salinity in the Bay of Bengal, i.e. weak (resp. strong) Indian monsoon, correspond to cold (resp. warm) events in the North Atlantic and Arctic, as documented by the... |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37572/36845.pdf |
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| Paterne, Martine; Kallel, Nejib; Labeyrie, Laurent; Vautravers, Maryline J.; Duplessy, Jean-claude; Rossignol-strick, Martine; Cortijo, Elsa; Arnold, Maurice; Fontugne, Michel. |
| The Mediterranean Sea hydrology at the time of the Heinrich formation in the North Atlantic Ocean was analyzed by comparing sea surface temperatures (SSTs) and oxygen isotope composition of seawater (delta w) changes during the past 75 kyr in two marine cores. These were compared to the palynological variations derived in the Mediterranean Sea core. During the last glacial the two oceanic SST records show similar and synchronous patterns, with several long-term cooling periods, ending by abrupt SST increases. At the time of the Heinrich events, cold SSTs and low salinity prevailed in the Mediterranean Sea. The freshwater budget was similar to the modern one, permitting the presence of a mixed forest on the Mediterranean borderlands. The post-Heinrich... |
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| Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35050/36799.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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| Jaouadi, Sahbi; Lebreton, Vincent; Bout-roumazeilles, Viviane; Siani, Giuseppe; Lakhdar, Rached; Boussoffara, Ridha; Dezileau, Laurent; Kallel, Nejib; Mannai-tayech, Beya; Combourieu-nebout, Nathalie. |
| Pollen and clay mineralogical analyses of a Holocene sequence from Sebkha Boujmel (southern Tunisia) trace the climatic and environmental dynamics in the lower arid bioclimatic zone over the last 8000 years. During the mid- to late Holocene transition, between ca. 8 and 3aEuro-kaaEuro-BP, a succession of five wet-dry oscillations is recorded. An intense arid event occurs between ca. 5.7 and 4.6aEuro-kaaEuro-BP. This episode marks the onset of a long-term aridification trend with a progressive retreat of Mediterranean woody xerophytic vegetation and of grass steppes. It ends with the establishment of pre-desert ecosystems around 3aEuro-kaaEuro-BP. The millennial-scale climate change recorded in the data from Sebkha Boujmel is consistent with records from... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53281/54321.pdf |
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| Dubois-dauphin, Quentin; Montagna, Paolo; Siani, Giuseppe; Douville, Eric; Wienberg, Claudia; Hebbeln, Dierk; Liu, Zhifei; Kallel, Nejib; Dapoigny, Arnaud; Revel, Marie; Pons-branchu, Edwige; Taviani, Marco; Colin, Christophe. |
| We present the neodymium isotopic composition (epsilon Nd) of mixed planktonic foraminifera species from a sediment core collected at 622m water depth in the Balearic Sea, as well as epsilon Nd of scleractinian cold-water corals (CWC; Madrepora oculata, Lophelia pertusa) retrieved between 280 and 442m water depth in the Alboran Sea and at 414m depth in the southern Sardinian continental margin. The aim is to constrain hydrological variations at intermediate depths in the western Mediterranean Sea during the last 20 kyr. Planktonic (Globigerina bulloides) and benthic (Cibicidoides pachyderma) foraminifera from the Balearic Sea were also analyzed for stable oxygen (delta O-18) and carbon (delta C-13) isotopes. The foraminiferal and coral epsilon Nd values... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53193/55001.pdf |
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| Magny, Michel; Combourieu Nebout, Nathalie; De Beaulieu, Jacques-louis; Bout-roumazeilles, Viviane; Colombaroli, D.; Desprat, Stephanie; Francke, A.; Joannin, Sebastien; Ortu, Elena; Peyron, Odile; Revel, Marie; Sadori, Laura; Siani, Giuseppe; Sicre, Marie-alexandrine; Samartin, S.; Simonneau, A.; Tinner, Willy; Vanniere, Boris; Wagner, B.; Zanchetta, Giovanni; Anselmetti, Flavio S.; Brugiapaglia, E.; Chapron, Emmanuel; Debret, Maxime; Desmet, Marc; Didier, Jean; Essallami, Latifa; Galop, D.; Gilli, A.; Haas, J.n.; Kallel, Nejib; Millet, L.; Stock, Andy; Turon, Jean-louis; Wirth, S.. |
| On the basis of a multi-proxy approach and a strategy combining lacustrine and marine records along a north-south transect, data collected in the central Mediterranean within the framework of a collaborative project have led to reconstruction of high-resolution and well-dated palaeohydrological records and to assessment of their spatial and temporal coherency. Contrasting patterns of palaeohydrological changes have been evidenced in the central Mediterranean: south (north) of around 40 degrees N of latitude, the middle part of the Holocene was characterised by lake-level maxima (minima), during an interval dated to ca. 10 300-4500 cal BP to the south and 9000-4500 cal BP to the north. Available data suggest that these contrasting palaeohydrological... |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37570/36902.pdf |
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