Skip to content

Magma recharge processes in continental flood basalt reservoirs: Evidence from the 1.27 Ga Coppermine River Group, Nunavut, Canada

Marie-Claude Williamson 1, Brian O\'Driscoll2

  • Affiliations: 1Geological Survey of Canada, Ottawa, Canada; 2Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada 

  • Presentation type: Talk

  • Presentation time: Tuesday 14:45 - 15:00, Room S160

  • Programme No: 4.1.3

  • Theme 4 > Session 1

Abstract

Large igneous provinces (LIPs) are high volume magmatic events that consist of flood basalts, gabbroic sills and dykes, and layered intrusions. LIPs are important targets for critical metals (e.g., Cu, Ni, Co, PGEs) hosted in mafic intrusions. The 1.27 Ga Mackenzie LIP of northern Canada includes flood basalts and feeder dykes of the Coppermine River Group (CRG), the Muskox layered intrusion, and the Mackenzie dyke swarm. Knowledge about the Ni-Cu-PGE prospectivity of the Mackenzie LIP is based on previous studies of the open-system Muskox intrusion and feeder dyke. In contrast, the mineral prospectivity of CRG flood basalts and feeder dykes is unknown. We present the preliminary results of a collaborative, multiscale investigation of the CRG aimed at (1) establishing the spatial distribution and interconnectivity of magma reservoirs as a key factor in developing structural traps hosting ore deposits, and (2) detailed mapping of the feeder system to resolve compositional links between the CRG and the Muskox intrusion. We report the results of a mineralogical study to characterize the crystal cargo(es) and textures of lava flows in the lowermost part of the CRG. Studies of lava-hosted mineral textures inform on host magma evolution and enable putative links to Muskox cumulates to be tested. Compositional zoning of silicate phases provides a snapshot of magmatic compositions for different stages in the evolution of the CRG volcanic system, including replenishment by Mg-rich magmas from deeper reservoirs. Such data have the potential to elucidate metallogenic processes associated with Ni-Cu ore genesis in the CRG.