Talk
Critical Minerals Geology and Exploration

A TGI-6 task force to help de-risk exploration for IOCG, IOA and affiliated primary critical metal deposits

Online pre-recorded

Author(s)

L. Corriveau (Presenting)
Geological Survey of Canada
J-F. Montreuil
Red Pine Exploration
O. Blein
Bureau de Recherches géologiques et minières (BRGM)
D. Beaulieu
Denendeh Exploration and Mining Company
R. Goad
Fortune Minerals Ltd

With estimated resources including 24 of the 31 critical metals on the Canadian list, iron oxide copper-gold (IOCG), iron oxide ± apatite (IOA) and affiliated primary critical metal deposits in metasomatic iron and alkali-calcic (MIAC) mineral systems are key to secure a long-term supply of critical metals for Canada. Canadian MIAC systems host undeveloped primary critical metal deposits such as the NICO Au-Co-Bi-Cu deposit in the Great Bear magmatic zone (NWT) and the Grenville Province Josette REE deposit (QC). Other systems have significant infrastructures, 100s of km of drill cores and robust geoscience datasets such as the Camsell River district explored by the Dene First Nations in the Great Bear magmatic zone, the Scadding Au-(Co) deposit in the Southern Province (ON) and the Romanet Horst in the Trans-Hudson Orogen (QC).

Research by the Targeted Geoscience Initiative and Geomapping for Energy and Minerals programs led to the development of an alteration (paragenetic) model that relates the alteration facies of MIAC systems to their mineralization and frames the genetic linkages between the systems’ multiple styles of mineralization and metal associations. This model stems from extensive alteration mapping of Canadian MIAC systems and global comparisons. It explains the diversity of deposit types in Australia and other global MIAC mining districts that include skarn, IOA (±REE, ±Ni), iron-rich Au-Co-Bi-Cu(± Ni, Se, Te, W), IOCG (±Pd, Pt, REE, U), albitite-hosted U-Au-Co or Mo-Re deposits. The billion tons of resources in some global MIAC districts provide a strong reminder of the considerable resources potential of Canada’s MIAC systems, including for critical metals. Yet vocabularies for mapping and logging MIAC systems are scanty and the collective ability to identify metasomatic (alteration) vectors to ore during regional mapping and exploration is fledging. Deposit models used for many Canadian MIAC-related prospects remain based on host rock types, structural controls or metal associations instead of on the metasomatic alteration facies that host mineralization. This situation undermines the identification of MIAC-affinities of mineralization in certain geological provinces of Canada and precludes the assessment of the mineral and development potential of those geological provinces.

To mitigate and solve some of the exploration challenges posed by the complexities of MIAC systems, TGI and its national and international collaborators pioneer the use of alteration facies, geochemical discriminant alteration diagrams and molar barcodes at regional to deposit scale to establish the MIAC frameworks of prospective Canadian settings and global mining districts, including in high-grade metamorphic terranes. The team is also assembling a terminology for mapping and core logging systems, and extensive photograph libraries, series of short courses and an atlas to synthesize shared signatures of Canadian settings and global MIAC mining districts. The research will provide a foundation for the mapping and exploration of MIAC systems in non to highly metamorphosed terranes where surface and near-surface resources are still to be discovered and mined as are those of the Great Bear magmatic zone and beyond.