A precise late Permian 40Ar/39Ar age for Central Iberian camptonitic lamprohyres
DOI:
https://doi.org/10.1344/105.000000346Keywords:
40Ar/39Ar dating, Lamprophyres, Variscan, Central Iberia, TranstensionAbstract
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.
References
Azor, A., González Lodeiro, F., Simancas, F., 1994. Tectonic evolution of the boundary between the Central Iberian and Ossa-Morena zones (Variscan belt, southwest Spain). Tectonics, 13, 45-61.
Bea, F., Corretgé, L.G., 1986. Petrography, geochemistry, and differentiation models of lamprophyres from Sierra de Gredos, Central Spain. Hercynica, 2, 1-15.
Bea, F., Montero, P., Molina, J.F., 1999. Mafic precursors, peraluminous granitoids, and late lamprophyres in the Avila batholith: A model for the generation of Variscan batholiths in Iberia. Journal of Geology, 107, 399-419.
Bea, F., Montero, P., Scarrow, J.H., Molina, J.F., 2002. The Gredos Sector of the Avila batholith, Central Iberia: An introduction. Gredos Seminar on Crustal Granites. Navarredonda de Gredos, 7-12 September 2002.
Bea, F., Montero, P., Zinger, T., 2003. The Nature and Origin of the Granite Source Layer of Central Iberia: Evidence from Trace Element, Sr and Nd Isotopes, and Zircon Age Patterns. Journal of Geology, 111, 579-595.
Bea, F., Villaseca, C., Bellido, F., 2004. El batolito de Avila (Sistema Central Español). In: Vera, J.A. (ed.). Geología de España. Madrid, Sociedad Geológica e Instituto Geológico y Minero de España, 101-110.
Bonin, B.L., Azzouni-Sekkal, A., Bussy, F., Ferrag, S., 1998. Alkali-calcic and alkaline post-orogenic (PO) granite magmatism: petrologic constraints and geodynamic settings. Lithos, 45, 45-70.
Dallmeyer, R.D., Lecorche, J.P., 1990. 40Ar/39Ar polyorogenic mineral age record in the northern Mauritanide orogen, West Africa. Tectonophysics, 177, 81-107.
Dewey, J.F., Holdsworth, R.E., Strachan, R.A., 1998. Transpression and transtension zones. In: Holdsworth, R.E., Strachan, R.A., Dewey, J.F. (eds.). Continental Transpressional and Transtensional Tectonics. Geological Society, London, Special Publication, 135, 1-14.
Farias, P., Gallastegui, G., González Lodeiro, F., Marquínez, J., Martín-Parra, L.M., Martínez Catalán, J.R., de Pablo Maciá, J.G., Rodríguez Fernández, L.R., 1987. Aportaciones al conocimiento de la litoestratigrafía y estructura de Galicia Central. Museu e Laboratório Mineralúgico e Geológico, Faculdade de Ciéncias, Universidade do Porto, Memórias, 1, 411-431.
Gradstein, F.M., Ogg, J.G., Smith, A.G., Agterberg, F.P., Blleker, W., Cooper, R.A., Davydov, V., Gibbard, P., Hinnov, L.A., House, M.R., Lourens, L., Luterbacher, H.P., McArthur, J., Melchin, M.J., Robb, L.J., Shergold, J., Villeneuve, M., Wardlaw, B.R., Ali, J., Brinkhuis, H., Hinden, F.J., Hooker, J., Howarrh, R.J., Knoll, A.H., Laskar, J., Monechi, S., Plumb, K.A., Powell, J., Raffi, I., Röhl, U., Sadler, P., Sanfilipp, A., Schmitz, B., Shakleton, N.J., Shield, G.A., Van Dam, J., van Kolfschoten, T., Veizer, J., Wilson, D., 2005. A Geological Time Scale 2004, Cambridge, Cambridge University Press, 589 pp.
MacDougall, I., Harrison, M.T., 1999. Geochronology and Thermochronology by the 40Ar/39Ar method. Oxford University Press, 269 pp.
Martínez Catalán, J.R., Martínez Poyatos, D., Bea, F., 2004. La Zona Centroibérica, Introducción. In: Vera J.A. (ed.). Geología de España. Madrid, Sociedad Geológica e Instituto Geológico y Minero de España, 68-69.
Montero, P., Bea, F., Zinger, T.F., Scarrow, J.H., Molina, J.F., Whitehouse, M.J., 2004a. 55 Million Years of Continuous Anatexis in Central Iberia: Single Zircon Dating of the Peña Negra Complex. Journal of the Geological Society, London, 161, 255-264
Montero, P., Bea, F., Zinger, T.F., 2004b. Edad 207Pb/206Pb en cristal único de circón de las rocas máficas y ultramáficas del sector de Gredos, Batolito de Ávila (Iberia Central). Revista de la Sociedad Geologica de España, 17, 157-165.
Orejana, D., Villaseca, C., Paterson, B.A., 2005. Geochemistry of pyroxenitic and hornblenditic xenoliths in alkaline lamprophyres from the Spanish Central System. Lithos, 86, 167-196.
Perini, J., Cabria, M., López-Ruiz, J., Doblas, M., 2004. Carboniferous-Permian mafic magmatism in the Variscan belt of Spain and France: implications for mantle sources In: Wilson, M., Neumann, E.R., Davies, G.R., Timmerman, M.J., Heeremans M., Larsen, B.T. (eds.). Permo-Carboniferous Magmatism and Rifting in Europe, Geological Society of London, Special Publication, 223, 415-438.
Qiu H.N., Wijbrans J.R., 2006. Paleozoic ages and excess 40Ar in garnets from the Bixiling eclogite in Dabieshan, China: new insights from 40Ar/39Ar dating by stepwise crushing. Geochimica et Cosmochimica Acta, 70, 2354-2370.
Vaughan, A.P.M., Scarrow, J.H., 2003. K-rich mantle metasomatism control of localization and initiation of lithospheric strike-slip faulting. Terra Nova, 15, 163-169.
Villaseca, C., Orejana, D., Pin, C., López García, J.A., Andonaegui, P., Encina, L., 2002. Estimación de la composición del manto subcontinental en el centro de España a partir de los materiales básicos hercínicos y post-hercínicos del Sistema Central Español. Geogaceta, 32, 15-18.
Villaseca, C., Huertas M.J., Orejana, D., Carracedo, M., Jiménez San Pedro J., Scarrow, J.H., 2004. Magmatismo filoniano tardi- y postvarisco. In: Vera J.A. (ed.). Geología de España. Madrid, Sociedad Geológica e Instituto Geológico y Minero de España, 124-128.
Wijbrans, J.R., Pringle, M.S., Koppers, A.A.P., Scheveers, R., 1995. Argon geochronology of small samples using the vulkaan argon laserprobe. Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen-Biological Chemical Geological Physical and Medical Sciences, 98, 185-218.
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