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| Michard, A; Montigny, R; Schlich, R. |
| Rare earth element abundances and Sr, Nd, Pb isotope compositions have been measured on zero-age dredge sample from the Rodriguez Triple Junction (RTJ) and the South-East Indian Ridge (SEIR). Along the SEIR, the geochemical "halo" of the St. Paul hot spot has a half-width of plus or minus 400 km and the data may be fairly well accounted for by a binary mixing between an Indian MORB-type component ( super(87)Sr/ super(86)Sr = 0.7028, super(143)Nd/ super(144)Nd = 0.51304, super(206)Pb/ super(204)Pb = 17.8) and the plume-type St. Paul component (0.7036, 0.5129, and 18.7 respectively). The RTJ has distinctive geochemical properties which contrast with those of the adjacent ridge segments. Low super(206)Pb/ super(204)Pb ratios which plot to the left of the... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37944/36025.pdf |
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| Schlich, R; Ball, G; Blanck, M; Boulanger, D; Boulanger, Mo; Bulot, A; Cantin, B; Doucoure, M; Durand, J. |
| The first Rodriguez Cruise started on 14 January 1984 from Colombo and ended at Reunion Island on 16 February 1984. The second cruise left Reunion Island on 3 April 1984 and was completed in Singapore on 7 May 1984. The program included a detailed Seabeam, gravimetric and magnetic survey of the Rodriguez Triple Junction over an area of 7,200 km super(2) and similar surveys of an axial segment of each of the 3 associated spreading ridges. The 2 cruises together total 27,000 km of profiles. The scientific objectives of the Rodriguez cruises based upon detailed bathymetric, gravimetric and magnetic mapping of the surveyed areas are summarized. |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37943/36024.pdf |
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| Munschy, M; Schlich, R. |
| The Indian Ocean is dominated by as system of 3 mid-ocean ridges converging at the Rodriguez Triple Junction located near 25 degree 30'S and 70 degree E. Numerous studies carried out on these 3 ridges provided the basic information on spreading rates and spreading directions. In 1984 the R/V Jean Charcot conducted a detailed survey over the Rodriguez Triple Junction and over an axial ridge segment located on each of the 3 associated ridges. The ridge axes are cut by distinct rift valleys; the depth of these rift valleys is a function of spreading rates. The rift valleys are not in isostatic equilibrium, but show clear density and mass deficits (0.4 to 0.8 g.cm super(-3) for spreading rate of 1 cm/a and 0.1 to 0.3 g.cm super(-3) for spreading rates of 3... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00268/37894/35975.pdf |
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| Weis, D; Frey, Fa; Schlich, R; Schaming, M; Montigny, R; Damasceno, D; Mattielli, N; Nicolaysen, Ke; Scoates, Js. |
| The gravity and bathymetric highs on the Kerguelen Plateau in the southern Indian Ocean between the Kerguelen Archipelago and Heard Island are seamounts formed of Miocene alkalic basalts similar to those found on the islands. Dredging during the Kerimis survey cruise recovered >1 ton of mostly basaltic rocks. One of the dredges (D6) yielded a large volume of in situ alkalic picritic pillow basalts, the first picritic lavas recovered that are related to the Kerguelen plume. K-Ar and Ar-40-Ar-39 ages are between 18 and 21 Ma for all but one sample, and these ages are only slightly younger than the main phase of volcanism on the archipelago. The dredged lavas form three distinct groups based on chemical and isotopic compositions. Incompatible element... |
| Tipo: Text |
Palavras-chave: Kerguelen; Trace elements; Isotopes; Mantle plume; Hot spot track; Picrites; Geochemistry; 1025 Geochemistry : Composition of the mantle; 1040 Geochemistry : Isotopic composition/chemistry; 1065 Geochemistry : Trace elements (3670). |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33407/31856.pdf |
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