Miocene to Messinian deformation and hydrothermal activity in a pre-Alpine basement massif of the French western Alps: new U-Th-Pb and argon ages from the Lauziere massif. (Articolo in rivista)

Type
Label
  • Miocene to Messinian deformation and hydrothermal activity in a pre-Alpine basement massif of the French western Alps: new U-Th-Pb and argon ages from the Lauziere massif. (Articolo in rivista) (literal)
Anno
  • 2010-01-01T00:00:00+01:00 (literal)
Alternative label
  • Gasquet D.; Bertrand J.; Paquette J.; Lehmann J.; Ratzov G.; Guedes R.; Tiepolo M.; Boullier A.; Scaillet A.; Nomade S. (2010)
    Miocene to Messinian deformation and hydrothermal activity in a pre-Alpine basement massif of the French western Alps: new U-Th-Pb and argon ages from the Lauziere massif.
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Gasquet D.; Bertrand J.; Paquette J.; Lehmann J.; Ratzov G.; Guedes R.; Tiepolo M.; Boullier A.; Scaillet A.; Nomade S. (literal)
Pagina inizio
  • 227 (literal)
Pagina fine
  • 241 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 181 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#note
  • In: Bulletin de la Societe Geologique de France, vol. 181 pp. 227 - 241. Societe Geologique de France, 2010. (literal)
Titolo
  • Miocene to Messinian deformation and hydrothermal activity in a pre-Alpine basement massif of the French western Alps: new U-Th-Pb and argon ages from the Lauziere massif. (literal)
Abstract
  • U-Pb and Th-Pb dating of monazite from hydrothermal quartz veins (\"Alpine veins\") from the Lauzière massif (North Belledonne) together with Ar/Ar ages of adularias from the same veins constrain the age of the last tectono-metamorphic events that affected the External Crystalline Massifs (ECM). Ages obtained are surprisingly young. The study of the structural context of the veins combined with our chronological data, allow us to propose a tectonic scenario of the northern ECM for the 15-5 Ma period, which was poorly documented so far. The quartz veins are of two types: (i) the oldest are poorly mineralized (chlorite and epidote), flat-lying veins. The quartz fibres (= extension direction) are near vertical and seem to be associated with a subvertical dissolution schistosity superimposed upon an early Alpine deformation underlined by \"mini-biotite\". They bear a sub-horizontal stretching lineation; (ii) the youngest veins are very rich in various minerals (anatase, rutile, phénacite, meneghinite, beryl, synchysite, ....). They are almost vertical. Their \"en echelon\" geometry as well as the horizontal attitude of their quartz fibres show a dextral strike-slip regime. Two groups of Th-Pb ages have been obtained: 11 to 10 Ma and 7 to 5 Ma. They were obtained from the most recent veins (vertical veins) sampled in different areas of the massif. The ca. 10 Ma ages are related to veins in the Lauzière granite and its metamorphic country-rocks at about 2 km from the eastern contact of the massif, while the ages of ca. 5 Ma correspond to veins occurring in mylonites along this contact. Adularias provided Ar/Ar ages at ca. 7 Ma. By contrast, a monazite from a vein of the Pelvoux massif (Plan du Lac) yielded a Th-Pb age of 17.6 Ma but in a different structural setting. Except fission track ages, there are very little ages of this range published in the recent literature on the Alps. The latter concern always gold mineralized veins (NE Mont Blanc and SW Lepontine dome). The last c (literal)
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