Publications des scientifiques de l'IRD

Kilzi M. A., Grégoire Michel, Bosse V., Benoit M., Driouch Y., de Saint Blanquat M., Debat P. (2016). Geochemistry and zircon U-Pb geochronology of the ultramafic and mafic rocks emplaced within the anatectic series of the Variscan Pyrenees : the example of the Gavarnie-Heas dome (France). Comptes Rendus Geoscience, 348 (2), p. 107-115. ISSN 1631-0713.

Titre du document
Geochemistry and zircon U-Pb geochronology of the ultramafic and mafic rocks emplaced within the anatectic series of the Variscan Pyrenees : the example of the Gavarnie-Heas dome (France)
Année de publication
2016
Type de document
Article référencé dans le Web of Science WOS:000373518700003
Auteurs
Kilzi M. A., Grégoire Michel, Bosse V., Benoit M., Driouch Y., de Saint Blanquat M., Debat P.
Source
Comptes Rendus Geoscience, 2016, 348 (2), p. 107-115 ISSN 1631-0713
The origin and evolution of ultramafic (UM), mafic (M) and intermediate rocks emplaced within the metamorphic and anatectic series of the middle crust of the Variscan segment of the Pyrenees are defined in the light of new isotopic data U-Pb zircon ages, and Sr, Nd isotopic ratios. In the Gavarnie-Heas dome (central Pyrenees), ultramafic, mafic and intermediate rocks form three massifs several kilometers in size emplaced within the anatectic series: (i) the Gloriettes massif, which mostly consists of norites with enclaves of ultramafic rocks; (ii) the Troumouse massif, which comprises intermediate rocks (gabbro-diorite and diorite) with norite enclaves, and (iii) the Aguila massif, which consists of intermediate rocks with homblendite enclaves. U-Pb zircon geochronology (first data for these rock types in the Axial Zone of the Pyrenees) revealed an age of 294 Ma for the diorite crystallization and correlatively for the crystallization of the anatectic granite. This new radiometric age allows us to suggest that the Variscan orogeny continued at least until the Early Permian and spread over around 30 Ma. The Nd and Sr isotopic compositions of all UM and M samples plot within the field of the continental crust. Two scenarios can explain the genesis and the emplacement of the components of the magmatic suite: i) evolution of mantle melts and contamination (AFC); ii) evolution of melts originating from a heterogeneous source (mantle + crust) at the local or regional scale. The strong crustal affinity of all UM and M rock types from Gavarnie-Heas leads us to favor the second scenario.
Plan de classement
Géologie et formations superficielles [064] ; Géophysique interne [066]
Description Géographique
FRANCE ; PYRENEES
Localisation
Fonds IRD
Identifiant IRD
PAR00014565
Contact