Gilles Manac'h's research while affiliated with French National Centre for Scientific Research and other places

Publications (7)

Article
Full-text available
The present study is focused on the so-called High Temprature Reaction Zone of the Oman ophiolite, a thin zone located between the roots of the sheeted dyke complex and the high-level gabbros marking the roof of the fossil magma chambers. The distribution of diabases, chloritised dykes, spilitized dykes and epidosites (in the order of increasing hy...
Article
The Blanco Trough (Juan de Fuc • Ridge) exposes • continuous section of upper oceanic crust (b • s • lts • nd di • b • ses) that h • s been hydrothermally • ltered in • transform f • ult environment. Microthermometric measurements on fluid inclusions • nd stable oxygen isotope compositions of whole rocks • nd secondary minerals from pillow l • v •...
Article
The Blanco Trough (Juan de Fuca Ridge) exposes a continuous section of upper oceanic crust (basalts and diabases) that has been hydrothermally altered in a transform fault environment. Microthermometric measurements on fluid inclusions and stable oxygen isotope compositions of whole rocks and secondary minerals from pillow lava and diabase units we...
Article
The Blanco trough (Juan de Fuca ridge) exposes a continuous section of the upper part of the oceanic crust (basalts and sheeted dykes) hydrothermally altered in a transform fault context. Coupled microthermometric measurements on fluid inclusions and stable oxygen isotope compositions of secondary phases from the diabase unit were performed to inve...
Article
Full-text available
During July and August 1991, the French-American Blanconaute dive program used the French submersibleNautile to investigate the West Blanco Depression (WBD), a deep, elongate trough located at the intersection of the Blanco Transform Fault Zone with the southern Juan de Fuca Ridge (JdFR). Twenty dives were carried out along the north wall of the WB...
Article
The north wall of the West Blanco Depression exposes, over more than 60 km in length and 1.5 km in height, a massive diabase unit (700 m visible), overlain by a basaltic flow unit (about 800 m thick), formed at the Juan de Fuca Ridge axis during the last 1.5 Ma. These N-MORB-type basalts show from east to west a remarkable evolution of their degree...

Citations

... Concernant l'étude microthermométrique, nos données ont été comparées avec des données microthermométriques acquises à la base de croûte océanique fossile et actuelle (Manac'h et al., 1999) (Fig. E.7). Les données de Manac'h et al. (1999) concernent une section allant des laves en coussin jusqu'à la base du complexe filonien accessible dans la fosse de Blanco en contexte transformant, à l'extrémité sud de la ride Juan On peut remarquer que nos données d'IF dans les différents types d'épidosite ont globalement une salinité inférieure à celle de l'eau de mer, à l'inverse des données de Kelley et al. (1992) et Manac'h et al. (1999, qui sont dans l'ensemble décalées au-dessus de la droite représentant la salinité de l'eau de mer (Fig. E.7). ...
... Although the presence of spheroidal pores with a relatively large aspect ratio has been previously suggested based on theoretical considerations (Collier & Singh, 1998;Kim et al., 2019;Shearer, 1988;Spudich & Orcutt, 1980), we provide the first direct evidences that low V P /V S is caused by the spheroidal pores in epidosites from the Oman ophiolites. Epidosites are ubiquitous in ophiolite complexes, and formed as a consequence of the extensive waterrock interactions at the seafloor spreading axes (Juteau et al., 2000;Schiffman et al., 1987;Weber et al., 2021). Epidosites occur mostly in the sheeted dike units close to the underlying gabbros in the Troodos ophiolite (Richardson et al., 1987), whereas recently epidosites are also recognized in the volcanic sequences (Gilgen et al., 2016). ...
... northern walls of the Blanco transform fault and Hess Deep rift, respectively. The geologic stratigraphy has been characterized at both study regions using manned submersibles and remotely operated vehicles [Francheteau et al., 1990[Francheteau et al., , 1992Juteau et al., 1995;Tivey et al., 1998;Karson et al., 2002aKarson et al., , 2002b. ...