Volcanic stratigraphy and structure in the Hunter Creek Fault area, Rouyn–Noranda, Quebec

The Hunter Creek Fault (HCF) has been considered in the past as a major synvolcanic fault marked by a change in volcanic facies and separating two geologically distinct blocks within the Noranda volcanic complex: the North Mine and the Central Mine sequences. Detailed mapping in the HCF area, in conjunction with petrographic and geochemical studies, has revealed that most of the volcanic units defined south of the fault zone also occur on its northern side. Field and drill-hole correlations indicate that the rocks are cut by a N240–N250 reverse-slip fault dipping approximately 70° toward the northwest. Major- and trace-element data suggest that least-altered volcanic rocks are of tholeiitic affinity and that there is no calc-alkaline unit in the HCF area.