Newly released paper discusses MT applications and implications in the Red Lake Greenstone belt following Metal Earth initiative using SPARTAN MT .
Crustal conductivity footprint of the orogenic gold district in the
Red Lake greenstone belt, western Superior craton, Canada
Ademola Q. Adetunji1, Gaetan Launay1, Ian J. Ferguson2, Jack M. Simmons1, Chong Ma1, John Ayer1 and Bruno Lafrance1
1Mineral Exploration Research Centre (MERC), Harquail School of Earth Sciences, Laurentian University, Sudbury, ON P3E2C6, Canada
2Department of Earth Sciences, University of Manitoba, Winnipeg, MB R3T2N2, Canada
A magnetotelluric (MT) study across the Red Lake greenstone belt of the western Superior craton, Canada, images a 50-km-long north-dipping conductor (<20 Ω·m) at 20–25 km
depth and subvertical conductors spatially correlated with crustal-scale shear zones and
large orogenic gold deposits. The conductors are interpreted to be the conductivity signature
of the deep crustal source of the auriferous fluids and pathways of the orogenic gold system. The geophysical results, supported by existing geochemical and fluid inclusion studies,
suggest that the Au- and CO2-rich fluids responsible for gold mineralization were released
by devolatilization of supracrustal rocks underthrust to mid- to lower-crustal levels during
subduction. This MT study links shallow gold mineralization to a deep crustal source region,
demonstrating the connection between a crustal suture zone and the formation of orogenic
gold deposits in an Archean greenstone belt.
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