Análisis e interpretación de los materiales volcánicos del Cerro de los Frailes (Cabo de Gata. Almería)

Abstract

The formation of Los Frailes volcano had two stages, which produced amphibole andesites (Frailes-I) and two-pyroxene andesites (Frailes-II) respectively, Iying on the extension of the dacites and andesites of the southernmost Cabo de Gata volcanoes (Revancha-Sabinal). The FRAILES-I stage is discontinuous, and has mainly produced domes and autoclastic breccias, in addition to an intermediate level of pumice-and-ash flow; this unit has some intercalated sedimentary levels. To the NE it is covered by a formation of sedimentary and hydroclastic rocks. The Frailes-II stage is continuous, and has formed some lava flows, the two summit domes, and sorne pyroclastic rocks of scarcely explosive origin. Other volcanic features are some domes and dikes of biotite-amphibole dacites, which affect to the Frailes-I-group; these are the southern continuation of the dacitic volcanic group of Rodalquilar-Rellana-Garbanzal. The generally accepted idea of a succesion in Cabo de Gata of cycles which started very explosively and ended with subvolcanic extrussions (domes) does not seem to be very realistic at least in the building of Los Frailes. A review of geochronological data, and the field disposition of the described materials does not discard the hypothesis that the pyroxene andesites of FrailesI-I might have been formed simultaneously or even than later the ignimbritic dacites of the Rodalquilar group.