The Labrador Central Mineral Belt IOCG Province - A Uranium-rich end member

2006

The eastern portion of the Central Mineral Belt of Labrador hosts two historically-defined uranium resources and a large number of earlier stage uranium prospects. The region is currently being explored by a number of Junior Companies, including Aurora Energy. Uranium mineralization and minor associated Cu and Au mineralization show a strong spatial correlation with the 1860Ma Aillik Volcanic sequence and the slightly younger Makkovikian plutons that intrude it. Alteration associated with the mineralization includes magnetite, hematite, actinolite, albite and other IOCG-style accessory minerals in both veins and disseminated alteration which can occur on up to km-scale. There is a demonstrable outcrop-scale correlation between U-mineralization and iron oxide alteration. Mineralization is texturally and structurally synchronous with the approximately 1800Ma Makkovikian orogeny. These characteristics, along with the spatial and temporal correlation between the Makkovik Province and the Svecofennian Mobile Belt which hosts IOCG mineralization in Scandanavia, support an IOCG setting for mineralization in the region. The Aillik Volcanics and Makkovikian plutons are U-enriched and were the most likely source for the uranium in the deposits. Fluid circulation is interpreted to have been driven by a combination of Makkovikian deformation and the thermal effects of synchronous plutons. Mineralization appears to have been spatially localized by a combination of structural traps and geochemical sinks, including reduced sediments, mafic-felsic contacts and chemically contrasting syndeformational instrusives.

Keywords: IOCG, Uranium, Exploration