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oai:docta.ucm.es:20.500.14352/569372024-07-19T16:29:44Zcom_20.500.14352_14col_20.500.14352_15

Cronología Rb-Sr y K-Ar de diques de la Sierra de Guadarrama (Sistema Central Español) Galindo Francisco, María Del Carmen Huertas Coronel, María José Casquet Martín, César 550.93(234.1) Geocronología Rb-Sr Geocronología K-Ar Diques Sierra de Guadarrama Sistema Central Español. Petrología 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. Depto. de Mineralogía y Petrología Fac. de Ciencias Geológicas TRUE pub 2023-06-20T16:46:23Z 2023-06-20T16:46:23Z 1994 journal article https://hdl.handle.net/20.500.14352/56937 0213-683X spa open access application/pdf Sociedad Geológica de España