Rodingites et autres inclusions du complexe ophiolitique de l'Eubée centrale (Grèce): région Mont-Kandyli - Col d'Aghios

Article Article scientifique Article Rodingites et autres inclusions du complexe ophiolitique de l'Eubée centrale (Grèce): région Mont-Kandyli - Col d'Aghios - Pagonda fre 1980 author Bertrand Jean 25466 author Economou Chryssoula 57779 author Skounakis S. 225-254 10.5169/SEALS-739491 1661-464X The island of Euboea lies along the SE coast of the mainland of Greece. Structurally it belongs to the Pelagonian zone. In the litterature there are two opposing hypotheses to explain the origin and emplacement of the ophiolites: 1) A Pelagonian micro-continent separated an internal oceanic basin from an external one. Following this hypothesis the ophiolites were derived from the external basin. 2) A single ocean (Tethys) existed and was located in what is now the Vardar zone. In this case the ophiolites, including those of Euboea, were thrust from the NE towards the SW. According to most authors a chaotic assemblage ("diabase-chert formation", etc.) has been described lying on top of a continental "basement" of Jurassic limestones. During Upper Jurassic- Lower Cretaceous times this chaotic assemblage was overthrust by a nappe composed mainly of peridotites and serpentinites. The higher members of this ophiolitic sequence, gabbros, diabases, etc., are thought to have been eroded before the transgression of Upper Cretaceous limestones. In the region studied, such a succession is not obvious in the field. Four sections are described, three of which contain good zones of rodingites. The rock enclosing the rodingites is a peridotite, usually highly or completely serpentinized. From a study of the relics of primary minerals the original peridotite appears to have been a harzburgite tectonite with lherzolitic affinities. The rodingites occur either in lenses, as dikes or in zones of differentiation. They are derived from diabases or gabbros (either in dikes or differentiated gabbroic zones). Except in a few rare cases a great development of calc-silicates is observed in these rodingites. The only important original mineral which is more or less preserved is pyroxene. Garnet is the most developed calc-silicate. The lattice spacing "a" varies between 11,883 Å and 12,072 Å, indicating a range in composition from an almost non-hydrated grossular to a completely hydrated one. Other calc-silicates include prehnite, clinozoisite, zoisite, xonotlite and vesuvianite. In some specimens calcite also seems to have taken part in the process of rodingitization. In addition to being replaced by garnet, the pyroxene often alters to actinolite-tremolite. Generally speaking, the chloritized zones near the contact with the enclosing serpentinite are either very poorly or not developed at all. Some examples of slightly or partially rodingitized gabbroic rocks are illustrated to show that some of the rodingites described could have such an origin. Texte en français avec résumé en anglais Dewey 550 141 Département de minéralogie 152 false Archives des Sciences 33 1-3 d9b31676-520e-459b-95ad-71fac924dcdc Article (Published version) Public RODINGITES_A.pdf 15940339 application/pdf openAccess Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département de minéralogie

Title	Published in	Year	Views	Downloads

Rodingites et autres inclusions du complexe ophiolitique de l'Eubée centrale (Grèce): région Mont-Kandyli - Col d'Aghios - Pagonda	Archives des Sciences	1980	520	80
Ages radiométriques de quelques roches ophiolitiques de l'Île de Crète	Proceedings of the VI Colloquium on the geology of the Aegean region	1977	156	69

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