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| Boespflug, Xavier. |
| L'objet de ce travail est d'étudier les compositions isotopiques (Sr, Nd, Pb) et les teneur en éléments traces des laves de trois bassins arrière-arcs : le bassin d'Okinawa (Pacifique ouest), le bassin de Lau, et le bassin Nord-Fidjien (Pacifique sud-ouest). Les bassins arrière-arcs sont situés en arrière des zones de subduction, et sont le lieu de formation de nouvelle croûte océanique. Le but de cette étude est d'une part de rechercher l'origine des variations géochimiques au sein de chaque bassin, d'autre part de comparer les caractéristiques géochimiques des différents bassins avec leur évolution géodynamique. |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00034/14533/11821.pdf |
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| Auzende, Jean-marie; Boespflug, Xavier; Bougault, Henri; Dosso, Laure; Foucher, Jean-paul; Joron, Jean-louis; Ruellan, Etienne; Sibuet, Jean-claude. |
| Three cruises (POP 1, SEAPSO 3 and SEAPSO 4) carried out during the "Tour du Monde" of the R.V. Jean Charcot allow us to obtain new structural and geochemical data for the Okinawa, North Fiji and Lau basins. Taken together, the structural and geochemical data illustrate a difference in evolution stages of these sites. The less evolved stage is represented by the Okinawa basin, where accretion is evidenced only by volcanic intrusion into a thinned continental crust. The most evolved stage is illustrated in the North Fiji basin, where the present-day accretion can be directly compm·ed to the East Pacific Ridge. The Lau basin displays an intem1ediate stage with a complex system of accretionary ridges. This difference in the evolution stage is translated in... |
| Tipo: Text |
Palavras-chave: Ouest Pacifique; Bassins arriere arc; Structure; Accretion; Geochimie; West Pacific; Back arc basins; Structure; Accretion; Geochemistry. |
| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00119/23058/20893.pdf |
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| Boespflug, Xavier; Dosso, Laure; Bougault, Henri; Joron, Jean-louis. |
| Rock samples have been dredged clming S0-35 and SEAPSO JV cruises (1984 and 1985) from cliJTemnl spreading ridges in lhe Lau Basin, soulh-weslern Pacific. They were analyzed for major and lrace elemenls and isotopic ralios (Sr, Nd). Nmlhem Lau Basin samples show N-MORB type characlerislics, bolh in major andlrace elemenls, whereas soulhern Lau Basin ones are differenlialed and show significanl Ta-Nb negalive anomalies in lheir extended REE pallerns, which is characlerislic of subcluclion zones.lsolopic ralios (Sr, Nd) are quile helerogeneous and inlermediale bel ween MORB and island arc values. The norlhern Lau Basin Ridge has geochemical characlerislics suggeslive ofmedio-oceanic lype spreading, whemas lhe soulhem LauBasin Ridge (Valu Pa Ridge) wilh ils... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00119/23059/20894.pdf |
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