A Petrophysical Footprint of the Canadian Malartic Gold Deposit, Québec, Canada
Abstract
Detailed geochemical, mineralogical, and structural studies have shown that it is possible to map a well-defined metasomatic halo (i.e., Footprint) surrounding the Canadian Malartic gold deposit, which is located in the southern Superior Province adjacent to the Cadillac-Larder Lake fault zone. The deposit primarily hosted by metaturbidites, is also associated with mafic dikes and intermediate-felsic intrusions. Metamorphic grade, which affects mineralogy varies from greenschist to amphibolite facies over the project area. Density and susceptibility variations primarily reflect the differences between protoliths, and aeromagnetic maps can be used to outline geological contacts. A more in-depth assessment of physical property variations within an individual lithology reveals regions of enhanced (PLUS), or depleted (MINUS) susceptibility and density which reflect local mineralogical changes occasioned by interaction with gold-bearing fluids and now highlight the ore zones. Some rock units were more affected than others, for example, the mafic rocks show a systematic reduction in density associated with carbonate alteration in the deposit Footprint. Most anomalous signatures of both density and susceptibility are found near the ore zone. Most rocks exhibit obvious structural foliation and lineation. Yet, Anisotropic Magnetic Susceptibility (AMS) fabric studies also serve to define a similar ore deposit Footprint as seen by the anomalous physical properties. The rationale behind this observation is that localised mineralogical variations (i.e., presence / absence of biotite, or pyrrhotite) are detectable using magnetic property measurements. Thermomagnetic and frequency dependent susceptibility measurements show zonation of magnetite / pyrrhotite concentrations.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMNS008..03M
- Keywords:
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- 0920 Gravity methods;
- EXPLORATION GEOPHYSICS;
- 0925 Magnetic and electrical methods;
- EXPLORATION GEOPHYSICS;
- 0935 Seismic methods;
- EXPLORATION GEOPHYSICS;
- 0999 General or miscellaneous;
- EXPLORATION GEOPHYSICS