KIMBERLITE INDICATOR MINERAL (KIM) STUDIES IN THE WESTERN CANADIAN ARCTIC: ASSESSING THE POTENTIAL FOR UNDISCOVERED DIAMOND-BEARING KIMBERLITE AND THE IMPLICATIONS OF KIM BEDROCK INHERITANCE

The Geological Survey of Canada (GSC) has a long and integral history in supporting research and exploration for diamond-bearing kimberlites through the application of pathfinder kimberlite indicator minerals and their geochemical characterization. From the initial success of the Ekati diamond mine in 1998, Canada has become the 3^rd largest diamond producer, with production now at 5 mine sites, and several other properties undergoing advanced assessments. Canadian kimberlite exploration peaked in the 1990s, but continues in many areas including the Banks Island region in the western Canadian Arctic.

Banks Island has been the subject of drift and geophysical studies by 3 different companies over the past 20 years. Results have shown promise, and numerous kimberlite indicator minerals, including G10D garnets have been recovered, but no kimberlite bodies have been identified. Recent research by the GSC has sought to reassess past exploration results in light of fundamental revisions to the Quaternary glacial history. Supported by new targeted drift sample collections (stream sediments and till), and employing a range of geochemical analytical techniques in partnership with the Arctic Resources Laboratory at the University of Alberta (e.g., Ni-in-Garnet geothermometry, Lu-Hf isotopes in Ilmenite), we demonstrate the unique signature of Banks Island KIMs from known regional kimberlites. Results argue for continued prospectivity of the region for hosting undiscovered diamond-bearing kimberlite.

Our research has also identified a relatively unknown complication to the standard KIM glacial dispersal model. Unconsolidated Pliocene Beaufort Formation fluvial deposits on Banks Island are now recognized to contain KIMs. In some cases, individual bulk samples (~20 kg) returned >50 garnets, including G10Ds. This identifies a bedrock inheritance source of KIMs that needs to be rationalized in regional exploration studies. Field studies this summer have sought to further investigate the regional Beaufort Formation KIM story, seeking to discriminate KIMs from these deposits from those derived through regional glacial bedrock erosion.