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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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| 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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