|
|
|
|
|
| Decitre, S; Deloule, E; Reisberg, L; James, R; Agrinier, P; Mevel, C. |
| [1] Analyses of Li and Li isotopes in serpentinized peridotites have been performed using Thermo-Ionisation Mass Spectrometry (TIMS) and Secondary Ion Mass Spectrometry (SIMS) techniques on samples collected from the southwest Indian Ridge (SWIR). In the bulk samples, Li concentrations range from 0.6 to 8.2 ppm, while whole rock delta(6)Li values range from -2.9 to -14parts per thousand. In situ analyses display a greater range in both Li concentration (0.1-19.5 ppm) and Li isotopic composition ( -27 to +19parts per thousand), with the serpentinized portions having higher Li concentrations than the associated relict phases. These variations may reflect changes in Li partitioning and isotopic fractionation between serpentine and fluid with temperature and... |
| Tipo: Text |
Palavras-chave: Lithium; Isotopes; Geochemical cycle; Oceanic crust; Serpentinization. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33403/31860.pdf |
| |
|
| |
|
|
| Searle, Rc; Cannat, M; Fujioka, K; Mevel, C; Fujimoto, H; Bralee, A; Parson, L. |
| A continuous, domed detachment surface ( FUJI Dome) has been imaged on the very slow-spreading southwest Indian Ridge using deep-towed side-scan sonar, and has been investigated by manned submersible and sea-surface geophysics. The Dome is morphologically similar to other oceanic detachments, core complexes or mega-mullions. In addition to bathymetric mullions observed in ship-borne bathymetry, finer scale spreading-parallel striations were imaged with the side scan. On the detachment surface, metabasalt crops out near the termination, probably as part of a thin fault sliver. Gabbro and troctolite probably crop out near the summit of the dome. The rest of the detachment surface is covered with sediment and rubble which is basaltic except for a single... |
| Tipo: Text |
Palavras-chave: Southwest Indian Ridge; Detachment; Submersible; Magnetic; Gravity; Marine geology and geophysics : midocean ridge processes; Marine geology and geophysics :; Seafloor morphology and bottom photography. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00226/33706/32124.pdf |
| |
|
|
| Meyzen, Cm; Ludden, Jn; Humler, E; Luais, B; Toplis, Mj; Mevel, C; Storey, M. |
| We report new Sr, Nd, and Pb isotope data for Mid-Ocean Ridge Basalts (MORB) dredged between 35 and 69 degrees E along a similar to 4100 km section of the Southwest Indian Ridge (SWIR), which is one of the slowest spreading ridges of the global mid-ocean ridge system ( full rate of 16 mm yr(-1)). The SWIR appears isotopically more heterogeneous than other mid-ocean ridges over similar length scales and comparable sampling density. Isotopic variations are generally independent of ridge segmentation, and the degree of heterogeneity decreases from west to east. This decrease in heterogeneity correlates with the observed increase in axial depth and decrease in crustal thickness, commonly attributed to decreasing mantle potential temperature. Data for the... |
| Tipo: Text |
Palavras-chave: Southwest Indian Ridge; MORB; Isotopes; Indian Ocean; Lower crust; Mantle. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34286/32655.pdf |
| |
|
|
|
