%0 Journal Article
%A Alcock, James E.
%A Martínez Catalán, José Ramón
%A Arenas Martín, Ricardo
%A Díez Montes, Alejandro
%T Use of thermal modeling to assess the tectono-metamorphic history of the Lugoand Sanabria gneiss domes, Northwest Iberia
%D 2009
%@ 0037-9409
%U https://hdl.handle.net/20.500.14352/44355
%X The Lugo and Sanabria domes in Northwest Iberia have well constrained metamorphic and structural histories.Both occur in the Iberian autochthon and resulted from late-Variscan extensional collapse following crustal thickeningrelated to the Variscan collision. The two domes developed beneath large thrust sheets, are cored bysillimanite-orthoclase anatectic gneiss, preserve evidence of a steep thermal gradient (1 oC MPa-1), and exhibit a distinctdecrease in metamorphic grade to the east in the direction of nappe movement. Geochronological evidence indicatesthat the lower crust melted within  30 Ma of initial crustal thickening and that dome formation occurred within50 Ma.The histories of the two domes are considered as the basis for one-dimensional finite-difference models of thermalresponse to changes in crustal thickness. Results from thermal models suggest that thickening was limited to thecrust, provide a numeric explanation for timing and nature of granite magmatism, and indicate that high-temperaturemetamorphism and crustal anatexis may result directly from thermal relaxation, eliminating the need for significantmantle thermal contribution. Also, the models show that small differences in thickness of large, wedge-shaped thrustsheets can explain distinct P-T paths experienced by different limbs of the domes.
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