The relationship between the plutonic intrusions and the dyke swarm in the Los Pedroches batholith (Iberian Massif, Spain): Dykes as a paleotectonic and paleostress indicators
| Autor: | Carracedo, M., Larrea, F. J., Alonso Olazábal, A., Gil Ibarguchi, José I. |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | RUC. Repositorio da Universidade da Coruña instname |
| Popis: | [Abstract] 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 ofshoshonitic affinity, get offthis trend. The dacitic and rhyolitic dykes are cogenetic with and probably comagmatic with thegranodioritic plutonand thegranitic intrusions, respectively. The trachyandesites, locallyshows sin-plutonic relations with thegranodiorite bodyand might becogenetic 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 acrustal 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 ofsome dyke swarms can be use as a paleotectonic and paleostress indicators.. |
| Databáze: | OpenAIRE |
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