Primitive Permo-Triassic volcanism in the Canadian Cordillera tectonic and metallogenic implications

Abstract

Volcanogenic massive sulfide deposits of various ages, types, and geochemical affinities occur within allochthonous and para-autochthonous terranes of the Cordillera of western Canada. The terrane affiliation, age, and chemical association of volcanic rocks can be used as a guide in the exploration for volcanogenic massive sulfide mineralization. The Kutcho massive sulfide deposit occurs within volcanic rocks of the Kutcho assemblage, in the fault-bounded King Salmon allochthon in northern British Columbia. The Kutcho Creek deposit is characterized by a Permo-Triassic age of mineralization and primitive chemical and radiogenic isotope compositions of the host rocks which are distinct from those of other volcanogenic massive sulfide deposits in the Canadian Cordillera. The Kutcho deposit is interpreted to have formed within a primitive intraoceanic are environment, distinct from the setting ascribed to more typical felsic volcanic-hosted (kuroko) massive sulfide deposits. The age, mineralogy, and chemical and isotopic compositions of rocks from the Kutcho assemblage are comparable to those of two other fault-bounded silvers in the Cordillera, the Sitlika assemblage and the Venables Valley-Red Hill area. These similarities suggest that rocks from the three areas may have formed within the same period and tectonic environment; as such, the latter two areas are prospective for volcanogenic massive sulfide exploration in the Canadian Cordillera.