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| Daniau, Anne-laure; Goni, Maria Fernanda Sanchez; Martinez, Philippe; Urrego, Dunia H.; Bout-roumazeilles, Viviane; Desprat, Stephanie; Marlon, Jennifer R.. |
| Although grassland and savanna occupy only a quarter of the world's vegetation, burning in these ecosystems accounts for roughly half the global carbon emissions from fire. However, the processes that govern changes in grassland burning are poorly understood, particularly on time scales beyond satellite records. We analyzed microcharcoal, sediments, and geochemistry in a high-resolution marine sediment core off Namibia to identify the processes that have controlled biomass burning in southern African grassland ecosystems under large, multimillennial-scale climate changes. Six fire cycles occurred during the past 170,000 y in southern Africa that correspond both in timing and magnitude to the precessional forcing of north-south shifts in the Intertropical... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00181/29235/27640.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... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53281/54321.pdf |
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| Bout-roumazeilles, Viviane; Combourieu-nebout, N.; Desprat, S.; Siani, G.; Turon, J. -l.; Essallami, L.. |
| A multiproxy study coupling mineralogical, grain size and geochemical approaches was used to tentatively retrace eolian and fluvial contributions to sedimentation in the Sicilian Tunisian Strait since the last glacial. The eolian supply is dominant over the whole interval, excepted during the sapropel Si when riverine contribution apparently became significant. Saharan contribution increased during the B011ing Allerod, evidencing the persistence of aridity over North Africa although the northern Mediterranean already experienced moister and warmer conditions. The Younger Dryas is marked by proximal dust inputs, highlighting intense regional eolian activity. A southward migration of dust provenance toward Sahel occurred at the onset of the Holocene, likely... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37574/37005.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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| Montero-serrano, Jean-carlos; Bout-roumazeilles, Viviane; Carlson, Anders E.; Tribovillard, Nicolas; Bory, Aloys; Meunier, Guillaume; Sionneau, Thomas; Flower, Benjamin P.; Martinez, Philippe; Billy, Isabelle; Riboulleau, Armelle. |
| The comparison of geochemical and mineralogical characteristics of terrigenous sediments deposited in the northern Gulf of Mexico (GoM) during the Holocene and Last Interglacial (LIG) is used to document the impact of slight differences in insolation and ice-sheet retreat rates on moisture transfer and precipitation patterns over central North America. The records indicate distinct sedimentological signatures over the two time periods, which likely reflect a modification of the main detrital provenance during the LIG compared to the Holocene. Here we postulate that the observed differences in the terrigenous supply during the LIG relative to the Holocene reflect a northeast migration of the main precipitation belt over the Mississippi River watershed... |
| Tipo: Text |
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| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33833/32460.pdf |
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