Abstract

Melt inclusions in quartz phenocrysts from the El Salvador copper porphyry system (northern Chile) have a highly fractionated rhyolitic composition, distinctly different from the andesitic host rock. The melt inclusions composition is comparable with quartz-sanidine rhyolitic porphyries (45 to 41.5 Ma) suggesting the intrusion of mafic melt (andesitic to granodioritic; 42 to 41 Ma) in a felsic reservoir. Magma mixing processes may have induced the early release of copper-bearing fluids from the mafic magma, contributing to mineralization in the granodioritic porphyry complex. © 2003 E. Schweizerbart'sche Verlagsbuchhandlung.