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1 GEMOC National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, North Ryde, NSW 2109, Australia
2 Département de Géologie–Pétrologie–Géochimie, Laboratoire Transferts Lithosphériques, UMR 6524, Université Jean Monnet, 23 Rue du Docteur Paul Michelon, Saint-Etienne, 42023, France
3 Present address: LRMH—Château de Champs, 29 Rue de Paris, Champs sur Marne, 77420, France (e.mail: stephanie.touron{at}culture.gouv.fr)
Spinel lherzolites and harzburgites from Mont-Briançon and Marais de Limagne in the Devès volcanic district display coarse-grained to porphyroclastic microstructures and the modal content of volatile-bearing phases increases with the degree of deformation. Clinopyroxene and/or spinel are partly or totally reacted to amphibole. The coupled interpretations of trace-element, rare earth element (REE) and O–Sr–Nd data for clinopyroxene and amphibole indicate that the metasomatized mantle beneath Devès is a mixture of depleted and enriched mantle associated with an alkaline, high field strength element poor, and light rare earth element, U- and Th-rich carbonate-rich silicate fluid–melt metasomatic agent. Oxygen isotope and REE data for clinopyroxene–amphibole pairs indicate a (La/Yb)N enrichment related to an increasing metasomatic agent/rock ratio.
