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| Bougault, Henri; Treuil, Michel. |
| The MAPCO cruise of the R.V. Jean-Charcot (October-November, 1979) sampled zero-age basalts along the Mid Atlantic Ridge from the Azores triple junction to 24°N. Preliminary shipboard geochemical analyses together with previOusly collected data show that hygromagmaphile elements are not randomly distributed along the ridge. North from Hayes transform, the chondrite normalised diagrams of these elements show flat to enriched distributions for the most hygromagmaphile elements. South from this transform, these diagrams are systematically depleted for the most hygromagmaphile elements. These data are interpreted in terms of regional upper mantle heterogeneity. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/1980/publication-5417.pdf |
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| Bougault, Henri; Joron, Jean-louis; Treuil, Michel. |
| .-Alkali metals prove to be very sensitive to alteration process even if this process is moderate. It is very difficult to use these elements to trace magmatic processes since their concentration may Vary within an homogeneous "unaltered" unit. From all the basaltic units investigated, a classification of "low partition coefficient" elements is presented (Sc, Ti, V, Y, Zr, Nb, La-Tb , Hf, Ta, Th) . The incompatible elements ratios (Y/Tb, Zr/Hf, Nb/Ta) are constant in the samples studied and are nearly equal to the same ratios in chondrites. This is consistent with the existence of an homogeneous primordial mantle at the scale of the North Atlantic, compatible with a chondritic composition of the earth. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5253.pdf |
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