A precise late Permian 40Ar/39Ar age for Central Iberian camptonitic lamprophyres
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Scarrow, Jane Hannah; Bea Barredo, Fernando; González Montero, Pilar; Molina Palma, José Francisco; Vaughan, Alan P. M.Editorial
Universidad de Barcelona; Instituto de Ciencias de la Tierra Jaume Almera
Materia
40Ar/39Ar dating Lamprophyres Variscan Central Iberia Transtension
Date
2006Referencia bibliográfica
Scarrow, J.H.; et al. A precise late Permian 40Ar/39Ar age for Central Iberian camptonitic lamprophyres. Geologica Acta, 4(4): 451-459 (2006). [http://hdl.handle.net/10481/32071]
Sponsorship
This work has been supported by the Spanish CICYT project CGL2005-05863.Abstract
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 ± 0.9 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.