%0 Conference Proceedings %T Polyphased rare-element magmatism during lateorogenic evolution: geochronological constraints fromthe NW Variscan Iberia %+ Bureau de Recherches Géologiques et Minières (BRGM) (BRGM) %+ Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO) %+ Department of Earth Sciences [Stellenbosch] %A Melleton, Jérémie %A Gloaguen, Eric %A Frei, Dirk %< avec comité de lecture %B 21 st meeting of the International Mineralogical Association %C Johannesburg, South Africa %N GP13 – TIMING AND GENESIS OF MINERALIZATIONS: THE ISOTOPE RECORD - ORAL %P 288 %8 2014-09-01 %D 2014 %Z Sciences of the Universe [physics] %Z Sciences of the Universe [physics]/Earth Sciences %Z Sciences of the Universe [physics]/Earth Sciences/MineralogyConference papers %X U-Pb geochronological data were collected on columbite-tantalite from rare-elementpegmatites and granites (Li, Ta, Nb, Be, Sn) from the Iberian Variscan Massif in orderto investigate timing of rare-element events during the late evolution of the Variscanbelt and the connection with granitoid suites. Our data set emphasises three events: (i)The Argemela rare-element granite, from the Central Iberian Zone (CIZ), emplaced at326±3 Ma and predates the three main late orogenic granitoid suites, (ii) most of thestudied rare-element pegmatites of the LCT family from the Galicia-Trás-Os-MontesZone (GTOMZ) gave an average age of 310±5 Ma, contemporaneous with an earlysyn-D3 granodiorite-monzogranite suite and the syn-D3 two-micas granites suite; and(iii) The youngest event is dated at around 301±3 Ma and is marked by emplacements ofrare-element pegmatites of the LCT family in both the CIZ and in the South of theGTOMZ. This event postdates the late to post-D3 bt±crd-granodiorite-monzogranitesuite emplacements, which are probably not genetically related to rare-elementpegmatites. Several pegmatites dated during this study do not display contemporaneousages with neighbouring supposed "parent" granites.Contemporaneous rare-element pegmatites fields seem to be located along belts as it isobserved for granitoids suites. Considering both GTOMZ and CIZ fields, emplacementages look to decrease toward the South. This is in good agreement with the knownpropagation of deformation, metamorphism and magmatism between the differentgeotectonic zones of the Iberian Massif.Lower crustal processes are not at the origin of rare-element granite genesis since in theIberian Massif, RM magmatism is polyphased with at least three distinct events.Hypothetical sources of RM melts are supposed to be set in a middle to upper crustposition, as it has been shown for granitoid magmatism. %G English %L insu-01143295 %U https://insu.hal.science/insu-01143295 %~ OBSPM %~ INSU %~ BRGM %~ CNRS %~ UNIV-ORLEANS %~ ISTO %~ OSUC %~ GIP-BE %~ VOLTAIRE %~ PSL %~ OBSPM-PSL %~ ANR %~ BRGM-DO