Relación entre las intrusiones plutónicas y el complejo filoniano en el batolito de Los Pedroches (Macizo Ibérico, España)los diques como indicadores de ambientes paleotectónicos y paleoesfuerzos

Resumen

The Los Pedroches batholith (Iberian Massif, SW Spain) is composed by a large biotite ± amphibole granodiorite pluton and several, smaller variable porphyritic, biotite ± cordierite granite intrusions. A dyke swarm composed esencially by trachyandesites, dacites and rhyolites cross cut the batholith. The whole set of plutonic and subvolcanic rocks define a K-rich, calc-alkaline alumino-cafemic association; only the trachyandesitic dykes of shoshonitic affinity, get off this trend. The dacitic and rhyolitic dykes are cogenetic with and probably comagmatic with the granodioritic pluton and the granitic intrusions, respectively. The trachyandesites, locally shows sin-plutonic relations with the granodiorite body and might be cogenetic with mafic microgranular enclaves scattered through the granodiritic unit. The emplacement of the batholith and the dyke swarms is late-hercynian and postcollisional (300 Ma) and, was controled by a transtensional shear zone at a crustal scale. The dyke swarm use the tectonically generated fracture system during cooling and consolidation of the plutonic rocks: (i) R' type Riedel fractures for the trachyandesitic and dacitic dykes emplacement, and (ii) R type Riedel fractures for rhyolitic dykes emplacement. The arrangement of some dyke swarms can be use as a paleotectonic and paleostress indicators.