%0 Journal Article
%A Díaz García, Florentino
%A Arenas Martín, Ricardo
%A Martínez Catalán, José Ramón
%A González del Tánago, José
%A Dunning, Gregory R.
%T Tectonic Evolution of the Careón Ophiolite (Northwest Spain):A Remnant of Oceanic Lithosphere in the Variscan Belt
%D 1999
%@ 0022-1376
%U https://hdl.handle.net/20.500.14352/57758
%X Analysis of the Careoó Unit in the Ordenes Complex (northwest Iberian Massif) has supplied relevant data concerningthe existence of a Paleozoic oceanic lithosphere, probably related to the Rheic realm, and the early subduction-relatedevents that were obscured along much of the Variscan belt by subsequent collision tectonics. The ophiolite consistsof serpentinized harzburgite and dunite in the lower section and a crustal section made up of coarse-grained andpegmatitic gabbros. An Early Devonian zircon age (395±2 Ma, U-Pb) was obtained in a leucocratic gabbro. Thewhole section was intruded by numerous diabasic gabbro dikes. Convergence processes took place shortly afterward,giving rise to a mantle-rooted synthetic thrust system, with some coeval igneous activity. Garnet amphibolite,developed in metamorphic soles, was found discontinuously attached to the thrust fault. The soles graded downwardto epidote-amphibolite facies metabasite and were partially retrogressed to greenschist facies conditions. Thermobarometricestimations carried out at a metamorphic sole (T ≈ 650ºC; P ≈ 11.5 kbar) suggested that imbricationsdeveloped in a subduction setting, and regional geology places this subduction in the context of an early Variscanaccretionary wedge. Subduction and imbrication of oceanic lithosphere was followed by underthrusting of the Gondwanacontinental margin.
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