|Author||Peter, J M;
Harris, J; Wickert, L; White, H P; Maloley, M; McClenaghan, B;
Layton-Matthews, D; Thiessen, E; Chapman, J; James, D; Rivard,
B; Coulter, D|
|Abstract||Over the last several decades, discovery of new metal reserves and replacement of existing reserves in Canada has not kept pace with production, partly because many of the deposits located at or near
surface have been found using traditional exploration techniques. Cognizant of this fact, Natural Resources Canada, building on the recently completed Targeted Geoscience Initiative (TGI) 3, is embarking on TGI-4 that is focused on supporting
effective deep exploration for buried mineral deposits. As part of the new initiative, several technologies are being investigated that have potential application to mineral exploration in Canada, including the north. These include portable x-ray
fluorescence spectrometry (FPXRF), portable x-ray diffractometry, portable short wavelength infrared spectrometry, and airborne hyperspectral surveying. This talk discusses applications or potential applications to mineral exploration in a northern
context. Not all examples presented are from the north, but the findings are of relevance to northern exploration. |
FPXRF is being increasingly utilized in geological and geochemical applications. Benefits include non-destructive, in situ or ex
situ analysis, simultaneous multi-element quantitative and/or semiquantitative determinations, portability, excellent detection limits for many elements, high sample throughput, low cost per analysis, and essentially instantaneous results. FPXRF
instrument usability has been improved by technological developments (x-ray tubes, sensitive detectors, data reduction algorithms) that have increased the spectrum of elements that can be analyzed, the quality of the data, rate of data acquisition,
convenience, and user experience. Several case studies of their application will be presented, including volcanogenic massive sulfide (VMS) exploration vectoring in black shales. FPXRF can be used to discriminate between prospective and barren
horizons and determine element signatures associated with hydrothermal plume fallout and relative direction toward ancient seafloor vents.
Hyperspectral imaging has been used as a successful mineral exploration tool in hot, arid environments.
However, there are few case-studies in the public domain that demonstrate its efficacy under the unique geographic and cold climatic conditions of Canada's north, with minimal surface weathering, limited vegetation cover, and variable lichen cover.
For this reason, airborne hyperspectral surveys were recently flown, with support of federal SINED funding, over parts of several greenstone belts (Hackett River, Izok Lake, High Lake, Hope Bay) that host significant VMS and orogenic gold deposits in
Nunavut. Preliminary results for the Hope Bay belt show that there is a strong correlation between hyperspectrally mapped minerals (high-Al illites and chlorite) and selected lithologies and gold mineralization-associated hydrothermal alteration.
These datasets will be used in further research on methodology and algorithm development to maximize exploration effectiveness.
The technologies discussed here display great utility and applicability in northern exploration, and have a low