The effect of a Devonian granitic intrusion on the Weedon lower Paleozoic volcanogenic massive sulfide deposit, Eastern Townships, Quebec

Abstract

The Weedon volcanogenic massive sulfide deposit situated in the Eastern Townships of Quebec has undergone the thermal metamorphism by a late Devonian granitic intrusion. Previous field observations had shown that the pyritic ores were converted to pyrrhotitic ones at the immediate contact with granitic intrusive rocks. Metamorphism apparently involves a possible enrichment of Ti and Mg in the gangue fraction of pyrrhotitic ore and a decrease in Fe in silicates near the granitic rock. Sulphides near the granitic intrusion are Fe rich compared to the original pyritic sulphides removed from the contact. Textures displayed by massive sulfide ores near the contact are characterized by features indicative of recrystallization and mobilization.