A precise late Permian 40Ar/39Ar age for Central Iberian camptonitic lamprohyres


  • J.H. SCARROW Dept. Mineralogy and PetrologyUniversity of Granada, Campus Fuentenueva, 18002 Granada, Spain.
  • F. BEA Dept. Mineralogy and PetrologyUniversity of Granada, Campus Fuentenueva, 18002 Granada, Spain.
  • P. GONZÁLEZ MONTERO Dept. Mineralogy and PetrologyUniversity of Granada, Campus Fuentenueva, 18002 Granada, Spain.
  • J. F. MOLINA PALMA Dept. Mineralogy and PetrologyUniversity of Granada, Campus Fuentenueva, 18002 Granada, Spain.
  • ALAN VAUGHAN British Antarctic SurveyHigh Cross, Madingley Road, Cambridge, CB3 0ET, U.K.




40Ar/39Ar dating, Lamprophyres, Variscan, Central Iberia, Transtension


The Avila batholith of central Spain is composed, predominantly, of crustal-melt peraluminous granites cut by small-scale mafic alkaline bodies. Dating of the Gredos sector mafic camptonitic lamprophyre dykes was undertaken to constrain the Late Variscan tectonomagmatic evolution of the region. A well constrained late Permian, Capitanian, age of 264.5 ± 1.3 Ma was obtained by 40Ar/39Ar geochronology using amphibole separates. This new age clearly distinguishes the dykes from other episodes of alkaline mafic magmatism in the region. We suggest that the lamprophyre dykes were emplaced into already solidified granitoids after the tectonic control on magma generation changed from purely extensional to transtensional.


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