Resumen
The southern part of the Mid-Permian Chinquilchoro pluton consits of two approximately concentric lithofacies: an A lithofacies, external melanocratic and a leucocratic internal B lithofacies. The A lithofacies is formed by quartz diorite and quartz monzonite, and the B lithofacies lies in the limit between quartz monzodiorite and quartz monzonite. The contact between the two lithofacies is transitional and difuse. The two lithofacies are calcalkaline, metaluminous and ferric. The coexistence of both lithofacies can be explained by fractional crystallization from the same parental magma in an anorogernic tectonic environment.