Consulta: creatorFacets:"Leleu, Thomas"
Registros recuperados: 3
Data/hora: 09/06/2024 03:47:50

Variabilité spatio-temporelle de la composition des fluides hydrothermaux (observatoire fond de mer EMSO-Açores, Lucky Strike) : traçage de la circulation hydrothermale et quantification des flux chimiques associés
Provedor de dados: 5
Autores: Leleu, Thomas.
This thesis present a detailed study of the composition of high temperature fluid from the Lucky Strike hydrothermal field (37°N, Mid Ocean Ridge) collected during three sampling campaigns within the framework of the deep sea observatory EMSO-Azores. The hydrothermal field has developped around a fossil lava lake framed by three ancient volcanic cones. In 2013, the discovery of a new active site to the East of the system, and presenting an unprecedented fluid composition at Lucky Strike (low Cl concentration and high Fe and Mn concentration), lead to a new model of hydrothermal circulation based on chemical geothermobarometer (Si; Si-Cl) and geothermometer (Fe-Mn) applied to 13 venting sites. We defined 5 groups of sites based on their chlorinity and...
Tipo: Text
Palavras-chave: Fumeur noir; Variabilité spatio-temporelle; Circulation hydrothermale; Isotope; Séparation de phase; Isotope; Hydrothermal circulation; Phase separation; Black Smoker; Time-serie.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00692/80380/83501.pdf

First direct observation of coseismic slip and seafloor rupture along a submarine normal fault and implications for fault slip history
Provedor de dados: 5
Autores: Escartin, Javier; Leclerc, Frederique; Olive, Jean-arthur; Mevel, Catherine; Cannat, Mathilde; Petersen, Sven; Augustin, Nico; Feuillet, Nathalie; Deplus, Christine; Bezos, Antoine; Bonnemains, Diane; Chavagnac, Valerie; Choi, Yujin; Godard, Marguerite; Haaga, Kristian A.; Hamelin, Cedric; Ildefonse, Benoit; Jamieson, John W.; John, Barbara E.; Leleu, Thomas; Macleod, Christopher J.; Massot-campos, Miguel; Nomikou, Paraskevi; Paquet, Marine; Rommevaux-jestin, Celine; Rothenbeck, Marcel; Steinfuehrer, Anja; Tominaga, Masako; Triebe, Lars; Campos, Ricard; Gracias, Nuno; Garcia, Rafael; Andreani, Muriel; Vilaseca, Geraud.
Properly assessing the extent and magnitude of fault ruptures associated with large earthquakes is critical for understanding fault behavior and associated hazard. Submarine faults can trigger tsunamis, whose characteristics are defined by the geometry of seafloor displacement, studied primarily through indirect observations (e.g., seismic event parameters, seismic profiles, shipboard bathymetry, coring) rather than direct ones. Using deep-sea vehicles, we identify for the first time a marker of coseismic slip on a submarine fault plane along the Roseau Fault (Lesser Antilles), and measure its vertical displacement of ∼0.9 m in situ. We also map recent fissuring and faulting of sediments on the hangingwall, along ∼3 km of rupture in close proximity to the...
Tipo: Text
Palavras-chave: Submarine fault; Surface rupture; Earthquake; Fault slip; Neotectonics; Microbathymetry.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00344/45500/45051.pdf

Sulfate minerals control dissolved rare earth element flux and Nd isotope signature of buoyant hydrothermal plume (EMSO-Azores, 37°N Mid-Atlantic Ridge)
Provedor de dados: 5
Autores: Chavagnac, Valerie; Ali, Hassan Saleban; Jeandel, Catherine; Leleu, Thomas; Destrigneville, Christine; Castillo, Alain; Cotte, Laura; Waeles, Mathieu; Cathalot, Cecile; Laes, Agathe; Pelleter, Ewan; Nonnotte, Philippe; Sarradin, Pierre-marie; Cannat, Mathilde.
While hydrothermal vents are now thought to be a major source of dissolved iron to the oceans, they have always been considered to be a sink for the dissolved rare-earth elements (DREEs). However, true dissolved REE observations in hydrothermal plumes are still lacking. Here we report for the first time the DREE concentrations and neodymium isotopic compositions (DεNd) of buoyant hydrothermal fluids at Lucky Strike (Mid-Atlantic Ridge). We find that 27 to 62% of total hydrothermal DREEs are rapidly scavenged by anhydrite precipitation at the onset of buoyant plume formation. After this initial loss, all DREEs behave quasi-conservatively within the buoyant plume. Dissolved phase εNd (DεNd) in the evolving plume are identical to black smoker DεNd of +9.0 and...
Tipo: Text
Palavras-chave: Black smokers; Rare earth elements; Neodymium isotopes; Hydrothermal; Sulfate minerals; EMSO-Azores.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00456/56733/58511.pdf