U-Pb age determinations with an ion probe on zircons within orthogneisses from the Canigou Massif, eastern Pyrenees, give an emplacement age for their granitic protolith of 475±10 Ma (Arenigian). This invalidates the previous interpretation of basement-cover relationships between the orthogneisses and the overlying Lower Cambrian Canaveilles metasedimentary series, and corroborates the intrusive character of the orthogneisses, which is further supported by field evidence. The data also define two groups of inherited zircons (Paleo/Meso-Proterozoic and Cadomian) in addition to partial lead loss during the Hercynian Late Carboniferous high temperature-low pressure metamorphic event. These results are in agreement with ages reported from other orthogneissic bodies across the entire Variscan chain of western Europe, and indicate the existence of a widespread Cambro-Ordovician magmatic event.

New 40Ar/39Ar dating performed on Rare Metal Granites and W ± Sn deposits in the northern Limousin has provided evidence of two metallogenic episodes. An Early Namurian episode (c. 325 Ma) was contemporaneous with the emplacement of the large peraluminous leucogranite bodies, which are associated with small W ± Sn deposits, but also with some larger deposits, at Puy-les-Vignes (323.4 ± 0.9 Ma) and Moulin-Barret (323.7 ± 0.8 Ma) formed at a shallower level above cryptic granite plutons. These new data indicate that the metallogenic potential of the Namurian leucogranites might have been underestimated. Most other W ± Sn deposits in the northern Limousin area are attributed to a Mid-Westphalian episode (c. 310 Ma), and are contemporaneous with the emplacement of all the Rare Metal Granites. Both episodes were related to leucogranite emplacement and associated fluid circulations, but in two different geodynamic contexts. The Early Namurian episode may be related to syncollisional extension of the Variscan belt, whereas the Mid-Westphalian one occurs during generalized extension and rapid exhumation of the belt associated with the granulite-facies metamorphism of the lower lithosphere probably related to the delamination of the lower lithosphere. Thus, W ± Sn and rare metals (Ta, Nb, Be, Li) deposits are clearly temporally and probably genetically related to leucogranitic magmatism.

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