Silicification; hydrothermal alteration in an Archean geothermal system within the Amulet Rhyolite Formation, Noranda, Quebec

Abstract

Silicified andesitic flows, divided into two alteration facies; mottled (epidote-quartz altered) andesite and silicified andesite. Silicification was contemporaneous with volcanism. Silicified andesites of the Amulet Rhyolite are products of extensive regional alteration and present a larger exploration target for massive sulfide deposits than does proximal chloritic and sericitic alteration beneath orebodies.--Modified journal abstract.