Abstract:

SHORTENED! The Genex deposit (242 tonnes of copper concentrate at 21% to 27% Cu) is hosted in a 2 km thick, steeply dipping, bimodal succession of metavolcanic rocks correlated with the Blake River assemblage of the Abitibi greenstone belt, based on U/Pb geochronology and the bimodal character of the stratigraphy. The volcanic rocks are overlain by a volcaniclastic and epiclastic unit, and cut by Proterozoic Matachewan diabase dikes. Felsic metavolcanic rocks consist of tuff-breccias, normal graded lapilli-tuff to bedded-tuff sequences, minor felsic flows and flow breccias. The felsic metavolcanic rocks are FIIIa rhyolites, and were erupted or emplaced in an arc environment. Mafic metavolcanic rocks consist of pillowed and massive flows as well as minor pillow breccias and mafic tuffs. The mafic volcanic rocks are tholeiitic basalts, and were erupted or emplaced in an arc environment. The metavolcanic rocks in the Genex area are cut by numerous mafic and intermediate synvolcanic intrusions.