Cronología Rb-Sr y K-Ar de diques de la Sierra de Guadarrama (Sistema Central Español)
Two calcalkaline granite porphyries, an E-W and a N-S trending one, and three monzonitic dykes striking NE-SW, have been dated. For the first dyke a whole rock Rb-Sr isochrone age of 296±3 Ma, i.e. Upper Carboniferous, is obtained. However, the second dyke pro vides only a regression age of 314±31 M...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 1994 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | español |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/56937 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/56937 |
| Access Level: | acceso abierto |
| Palabra clave: | 550.93(234.1) Geocronología Rb-Sr Geocronología K-Ar Diques Sierra de Guadarrama Sistema Central Español. Petrología |
| Sumario: | Two calcalkaline granite porphyries, an E-W and a N-S trending one, and three monzonitic dykes striking NE-SW, have been dated. For the first dyke a whole rock Rb-Sr isochrone age of 296±3 Ma, i.e. Upper Carboniferous, is obtained. However, the second dyke pro vides only a regression age of 314±31 Ma. Whole rock K-Ar ages of the monzonitic dykes are 245±7,i.e. Lower-Middle Triassic, for two of them, and 220±5 for the third. The first age rises doubts about the up-to-the-present alleged posteriority of the E-W dykes relative to the large granitic plutonism in the area. The second is geologically reasonable within the limits of error only, as N-S dykes must be younger than the Cabeza Mediana pluton, which is 291 ±6 Ma old, and older than the hydrothermal episyenitic event dated at 274±6 Ma. For the monzonitic dykes the age of 245±7 Ma is taken as representative of the injection episode, whilst the second age probably results from superimposed alteration. This alkaline episode can be correlated with the opening of the Iberian trough. |
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