|
|
|
|
| |
|
|
| 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 |
| |
|
|
| Lartaud, Franck; Emmanuel, Laurent; De Rafelis, Marc; Pouvreau, Stephane; Renard, Maurice. |
| Compared to oxygen isotopes, the carbon isotope composition of biogenic carbonates is less commonly used as proxy for palaeoenvironmental reconstructions because shell delta C-13 is derived from both dissolved inorganic (seawater) and organic carbon sources (food), and interactions between these two pools make it difficult to unambiguously identify any independent effect of either. The main purpose of this study was to demonstrate any direct impact of variable food supply on bivalve shell delta C-13 signatures, using low/high rations of a C-13-light mixed algal diet fed to 14-month-old (adult) cultured Japanese Crassostrea gigas under otherwise essentially identical in vitro conditions during 3 summer months (May, June and July 2003, seawater temperature... |
| Tipo: Text |
|
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2010/publication-7435.pdf |
| |
|
|
| 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 |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00248/35925/34447.pdf |
| |
|
| |
|
|
| Huyghe, Dimitri; Emmanuel, Laurent; De Rafelis, Marc; Renard, Maurice; Ropert, Michel; Labourdette, Nathalie; Lartaud, Franck. |
| For decades, bivalve shells have constituted one of the most common supports for paleoclimatic archives based on stable isotope approaches. In this work, we conducted chemical marking and recapture techniques to study the fluctuation of δ18O values of oyster shells of the species Magallana gigas reared in natural environment in Normandy (France) for two years. The results were compared to the continuous monitoring of temperature and salinity and monthly records of seawater δ18O. Isotopic measurements were performed on the hinge area that regroups the whole life of the oysters. Here we demonstrate that oysters mineralized their shells with no significant growth breaks during the two-years experiment, even at temperatures below 6 °C. The results confirm that... |
| Tipo: Text |
Palavras-chave: Stable isotopes; Paleoclimatology; Sclerogeochemistry; Sclerochronology; Kinetic isotope effect. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00624/73622/73038.pdf |
| |
|
|
| Sisavath, Emmanuelle; Mazuel, Aude; Jorry, Stephan; Babonneau, Nathalie; Bachelery, Patrick; De Voogd, Beatrice; Salpin, Marie; Emmanuel, Laurent; Beaufort, Luc; Toucanne, Samuel. |
| The present study focused on turbidite sedimentation in the Cilaos turbidite system, a volcaniclastic deep-sea fan recently recognized offshore La Réunion Island. A set of piston cores was collected in order to establish the stratigraphy of this fan and to examine the processes controlling the turbidite sedimentation off the Cilaos cirque (Piton des Neiges volcanic massif) over the last climatic cycle. Two main phases of turbidite activity were identified, during the ca 140–127 ka and 30–0 ka periods, coinciding with the two last glacial–interglacial transitions (i.e., Terminations II and I). In addition to changes in climate and eustatic sea-level, these periods coincide with a low effusive volcanic activity of the Piton des Neiges volcano. The high... |
| Tipo: Text |
Palavras-chave: Turbidites; La Reunion Island; Indian Ocean; Late Quaternary; Volcaniclastic system. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00105/21659/19383.pdf |
| |
|
| |
|
|
| 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... |
| Tipo: Text |
|
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00202/31283/29690.pdf |
| |
|
|
|
