Physical and geometric controls on the distribution of magmatic and sulphide bearing phases within the Voisey's Bay nickel-copper-cobalt deposit, Voisey's Bay, Labrador

• Main Author: Evans-Lamswood, Dawn
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1999
• Subjects: Nain
• Online Access: https://research.library.mun.ca/6556/; https://research.library.mun.ca/6556/1/DawnEvansLamswood.pdf; https://research.library.mun.ca/6556/3/DawnEvansLamswood.pdf

The Voisey's Bay Ni-Cu-Co deposit occurs within fragment-bearing troctolites and olivine gabbros of the 1.34 Ga. Reid Brook Intrusive Complex, an early member of the predominantly anorthositic Nain Plutonic Suite (NPS). The NPS straddles the 1.85 Ga. Cratonic suture between Archean orthogneiss and the Nain Province to the east and Paleoproterozoic paragneiss of the Churchill Province to the west. -- The Reid Brook, Discovery Hill, Mini-Ovoid and Ovoid are mineralized zones within a sub-vertical conduit system, the Ovoid dyke. The Reid Brook zone is the most western mineralized zone of the Voisey's Bay deposit, it contains disseminated and massive sulphide hosted within the dyke and veins in the adjacent country rocks. Mineralization of the Discovery Hill zone, unlike the Reid Brook zone to the west, is confined to the dyke and does not penetrate the country rocks. The Mini-Ovoid is west, but is geologically continuous with the Ovoid. Mineralization consists of massive to semi massive and disseminated sulphides. The Ovoid is a cauldron-shaped body of massive to semi massive sulphides with less extensive parcels of disseminated sulphides. -- Striking east-west, the Ovoid dyke appears to post-date, but physically link two large troctolite intrusions, the Eastern Deeps chamber and the Western Deeps chamber. In the west, the conduit extends from the top of the Western Deeps chamber to the north margin of the Eastern Deeps chamber. Rather than being within the sub-vertical Ovoid dyke, mineralization of the Eastern Deeps zone is located within a sub-horizontal splay from the main conduit where it is connected to the base of the Eastern Deeps chamber. -- All the mineralized zones in the Voisey's Bay deposit comprise magmatic-textured sulphides within fragment-bearing troctolites and olivine gabbros. Sulphides within the system are preferentially concentrated in physical traps where topographic irregularities and variations in conduit morphology favour the capture, containment and precipitation of sulphides through ...