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TitleThe application of rapid potential field methods for the targeting of IOCG mineralisation based on physical property data, Great Bear magmatic zone, Canada
AuthorHayward, N; Enkin, R J; Corriveau, L; Montreuil, J -F; Kerswill, J
SourceJournal of Applied Geophysics vol. 94, 2013 p. 42-58,
Alt SeriesEarth Sciences Sector, Contribution Series 20120023
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthwest Territories
NTS85M; 85N; 86C; 86D; 86E; 86F; 86K; 86L
AreaGreat Bear Lake; Port Radium; Hottah Lake; Lac la Martre
Lat/Long WENS-120.0000 -116.0000 67.0000 63.0000
Subjectsgeophysics; geophysical interpretations; magnetite; alteration; mineral occurrences; bedrock geology; bouguer anomalies; exploration methods; Great Bear magmatic zone; NICO deposit; potential field interpretations; prospectivity mapping; Precambrian
ProgramIron-oxide Copper-gold (IOCG) / Multiple Metals - Great Bear Lake (NWT), GEM: Geo-mapping for Energy and Minerals
AbstractNew techniques for the integration of gravity and aeromagnetic data through rock physical property relationships are tested for the rapid location of potential iron oxide-copper-gold (IOCG) exploration targets across the Great Bear magmatic zone (GBMZ). These techniques are based on the recognition of coincident or near-offset magnetic and gravity anomalies associated with IOCG deposits, resulting from their intense and combined iron-oxide and alkali alteration. In the GBMZ, the NICO (Au-Co-Bi-Cu) deposit is an atypical magnetite-group IOCG hosted within an intensely hydrothermally-altered metasedimentary sequence. Prospectivity maps for the NICO area are derived from the integration of high-resolution aeromagnetic and surface gravity data with physical property measurements of magnetic susceptibility and density. Method 1 combines the pseudo-gravity (derived from the aeromagnetic data) and Bouguer gravity data to determine the locations of superimposed high anomalies. Method 2 estimates the apparent susceptibility and density subsurface distribution based on vertical prism models of the magnetic and gravity data. The apparent susceptibility data are transformed to apparent density using physical property relationships. The two apparent density datasets are then combined to determine the location of coincident magnetic and gravity derived anomalies. The results of these methods are supported by, and compared with, similar prospectivity maps generated through weights of evidence techniques. At NICO, the prospectivity maps accurately locate the deposit and nearby occurrences. Despite the lower resolution of the regional gravity data, application of the techniques across the GBMZ is successful at locating mineralised IOCG systems including the magnetite-group systems at Grouard, Fab, DeVries and Cole Lake, the magnetite to hematite-group systems of the Port Radium-Echo Bay district, and has highlighted possible targets for future exploration.