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| Bonneau, Lucile; Toucanne, Samuel; Bayon, Germain; Jorry, Stephan; Emmanuel, Laurent; Silva Jacinto, Ricardo. |
| In this study we used major element composition, neodymium isotopes ratios (εNdεNd) and concentration of REE to track and quantify the sediment routing in the Var sedimentary system from source (Southern French Alps) to sink (Ligurian Sea) over the last 50 ka. Our data reveal that changes in sediment sources over that period, associated with concomitant changes in the hyperpycnal (i.e. flood-generated turbidity currents) activity in the Var submarine canyon, were mainly driven by paleoenvironmental conditions in the upper basin and in particular by the presence of glaciers during the last glacial period. Based on this evidence, we determined when and how glacier-derived sediments were produced, then excavated and transferred to the ocean, allowing us to... |
| Tipo: Text |
Palavras-chave: Var; Routing system; Glacial erosion; Source-to-sink. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00358/46957/47130.pdf |
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| Bonneau, Lucile; Colin, Christophe; Pons-branchu, Edwige; Mienis, Furu; Tisnerat-laborde, Nadine; Blamart, Dominique; Elliot, Mary; Collart, Tim; Frank, Norbert; Foliot, Lorna; Douville, Eric. |
| U‐Th ages and temperatures derived from Li/Mg have been measured on coral fragments of Lophelia pertusa and Madrepora. oculata collected from two sediment cores, which were taken from cold‐water coral (CWC) mounds at 700 ‐ 790 m water depth at the SW Rockall Trough margin. Our data, combined with previous published data, have allowed us to firstly estimate the occurrence of CWC at the SW Rockall Trough margin during the Holocene and, secondly, to better constrain the environmental conditions driving variability in CWC growth. CWC abundance is marked by a pronounced increase in the mid‐Holocene (∼6 ka) and is modulated by millennial‐scale variability throughout the late Holocene. The mid‐Holocene proliferation of CWC coincides with lowest IRD abundances and... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00441/55260/56753.pdf |
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| Bonneau, Lucile; Jorry, Stephan J.; Toucanne, Samuel; Silva Jacinto, Ricardo; Emmanuel, Laurent. |
| Although it is widely accepted that erosion and sediment transfer respond to millennial-scale climatic variability, these changes remain difficult to detect in marine sedimentary archives. In the Var sediment-routing system, northwestern Mediterranean Sea, the absence of a continental shelf results in a direct connection between the Var River mouth and the deep basin during both highstand and lowstand conditions. This makes the Var sediment-routing system an ideal target to test whether rivers can transmit climate-driven high-frequency changes in sediment flux to the ocean. On the basis of an unprecedented (centennial-to-millennial-scale) resolution in turbidite sequences, we reconstructed the activity of turbidity current overflows along the deep-sea Var... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00248/35925/34447.pdf |
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| Dubois-dauphin, Quentin; Bonneau, Lucile; Colin, Christophe; Montero-serrano, Jean-carlos; Montagna, Paolo; Blamart, Dominique; Hebbeln, Dierk; Van Rooij, David; Pons-branchu, Edwige; Hemsing, Freya; Wefing, Anne-marie; Frank, Norbert. |
| The Nd isotopic composition (εNd) of seawater and cold-water coral (CWC) samples from the Gulf of Cádiz and the Alboran Sea, at a depth of 280-827 m were investigated in order to constrain mid-depth water mass dynamics within the Gulf of Cádiz over the past 40 ka. εNd of glacial and Holocene CWC from the Alboran Sea and the northern Gulf of Cádiz reveals relatively constant values (-8.6 to -9.0 and -9.5 to -10.4, respectively). Such values are similar to those of the surrounding present-day mid-depth waters from the Mediterranean Outflow Water (MOW; εNd ∼ -9.4) and Mediterranean Sea Water (MSW; εNd ∼ -9.9). In contrast, glacial εNd values for CWC collected at thermocline depth (550-827 m) in the southern Gulf of Cádiz display a higher average value... |
| Tipo: Text |
Palavras-chave: Neodymium isotopes; Cold-water corals; Mediterranean outflow water; East Antarctic intermediate water; Mediterranean sea water; Gulf of Cadiz. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00339/45047/44446.pdf |
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| Bonneau, Lucile; Jorry, Stephan; Toucanne, Samuel; Emmanuel, Laurent. |
| A ce jour, très peu d’étude ont mis en évidence l’impact des changements climatiques sur les transferts sédimentaires dans les enregistrements sédimentaires marins. Avec son plateau continental étroit, le système sédimentaire du Var est un site idéal pour l’étude des transferts terre-mer au cours du Quaternaire. Malgré les variations du niveau marin, son « deep-sea-fan » (ride sédimentaire du Var) est resté continuellement alimenté par un canyon directement connecté à l’embouchure du fleuve. L’activité turbiditique récente de ce système, dominée par les courants hyperpycnaux, est étroitement liée aux crues du Var. Le cadre chronostratigraphique de 3 carottes, longues de 20 mètres, prélevées dans les dépôts turbiditiques de la ride sédimentaire du Var a été... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00202/31283/29690.pdf |
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