Sediment travel paths in the Carboniferous as recorded by detrital zircon geochronology in the Dora-Maira and Zone Houillère

International audienceIn the internal zone of the European Alps, late Carboniferous to Permian sediments have been detached from theirbasement (e.g. the Zone Houillère in the Briançonnais Zone). The Pinerolo Unit (Dora-Maira Massif) is the deepest unitexposed in the stack of the Western Alps and is considered to be Carboniferous in age based on lithological considerations(Franchi & Novarese, 1895; Argand, 1911). The blueschist-facies Pinerolo Unit occupies a key tectonic position in theAlpine belt, being overthrusted by the coesite-eclogite and quartz eclogite units of the Dora-Maira Massif.Detrital zircon grains from the Pinerolo Unit and the Zone Houillère (located along the external margin of the Briançonnaisdomain) display similar age patterns, with the youngest and largest population being Carboniferous (340-330 Ma). Thedistribution of Carboniferous magmatism in the Alps and surrounding areas suggests that the detritus was transported fromMaures-Corsica and possibly from the Helvetic Zone into the Zone Houillère and the Pinerolo basin. Our results highlightthe potential of detrital zircon geochronology for deciphering the sources of detrital material in meta-sediments, even if theyhave been affected by metamorphic overprints