Spinel-free and spinel-poor dunite veins crosscutting the Wadi Rajmi ophiolite chromitite (northern Oman ophiolite)
- Autores: Khadidja Abbou-Kebir, Shoji Arai, Ahmed Hassan Ahmed, Georges Ceuleneer
- Localización: Bulletin de la Société Géologique de France, ISSN 0037-9409, Vol. 184, Nº. 3, 2013, págs. 261-266
- Idioma: inglés
- Títulos paralelos:
- Veines de dunites dépourvues ou pauvres en spinelles et recoupant un gisement de chromite podiforme dans le Wadi Rajmi (partie nord de l'ophiolite d'Oman)
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Resumen
Peculiar dunitic veins almost or totally free of spinels crosscut a podiform chromitite ore body in the Wadi Rajmi, northern Oman ophiolite. They probably originated from a komatiitic melt which was oversaturated in Fo<-94 olivines and which evolved to precipitate simultaneously both chromian spinels, with Cr# ranging from 0.6 to 0.8, and Fo91-93 olivines. The absence or the low modal amounts of spinels are possibly governed by a Cr-undersaturation state of the involved melt which crystallized under relatively low cooling rates to generate the spinel-free and the spinel-poor dunites. A shallow and highly depleted mantle source for this komatiitic melt was envisaged during a converging tectonic regime, initiated earlier in the dynamic history of the Oman ophiolite.
