Basaltes, andésites, dacites et rhyolites des stratovolcans des Nevados de Chilian et de l'Antuco (Andes méridionales): Ia remarquable illustration d'une différenciation par cristallisation fractionnée

Abstract The Nevados de Chilian and Antuco stratovolcanoes (36 °-37 dg S, southern Andes) erupt high-Al basalts, andesites, dacites and rhyolites. The lava series has no indication of contamination by the continental crust. Therefore, its differentiation is very well explained by crystal fractionation of the mineral phases present as phenocrysts (plagioclase, olivine, clinopyroxene, orthopyroxene, magnetite, ilmenite and apatite), taking into account major and trace elements. A fractionation model is presented here.