%0 Journal Article
%A Díez Fernández, Rubén
%A Martínez Catalán, José Ramón
%A Gómez Barreiro, Juan
%A Arenas Martín, Ricardo
%T Extensional Flow during Gravitational Collapse: A Tool forSetting Plate Convergence (Padrón Migmatitic Dome,Variscan Belt, NW Iberia)
%D 2012
%@ 0022-1376
%U https://hdl.handle.net/20.500.14352/42435
%X Plate convergence analysis in collisional orogens is usually based on the study of major contractional structures andstrike-slip shear zones. Here we show how the structural analysis of extensional structures may report the regionalor far stress field during relatively local, gravity-driven extensional collapse of a thickened continental crust and howthis information may be used to constrain the broad vectors of plate convergence at that time. The Padro´n migmatiticdome is a synconvergent extensional system developed in the axial zone of the Variscan belt exposed in the NW partof the Iberian Massif of Spain. This system affected the allochthonous and autochthonous sequences involved inPangaea’s assembly in Southern Europe. It includes three major extensional shear zones, which have been analyzedin detail to provide a wide ground data set for the discussion of the proposed model. The tectonic flow in the Padrónmigmatitic dome and in other coeval structures is characterized by vectors ranging from parallel to oblique, in thelatter case with a counterclockwise azimuth in relation to the trend of the orogenic belt. Our model suggests thatthe extensional collapse of the Variscan belt inNWIberia would have developed if the convergence between Gondwanaand Laurussia had not stopped and that it would have included a dextral component.
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