Precambrian oil inclusions in late veins and the role of hydrocarbons in copper mineralization at White Pine, Michigan

Abstract

Liquid oil was trapped as primary fluid inclusions in calcite crystals in late Cu-Fe sulfide-bearing veins that crosscut and offset the cupriferous shale deposit at White Pine. The age of the calcite (1047 ±35 Ma) is an entrapment age and thus a minimum age for the oil. Close temporal and spatial associations of oil and metallic sulfides in the late veins suggest that liquid and solid hydrocarbons may have been dominant controls of the main-stage White Pine copper mineralization.