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TitleMineral potential analyzed and mapped at multiple scales - a modified fuzzy logic method using digital geology
AuthorEddy, B G; Bonham-Carter, G F; Jefferson, C W
SourceGIS for the earth sciences; by Harris, J R (ed.); Geological Association of Canada, Special Paper 44, 2006 p. 143-162
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20070166
PublisherGeological Association of Canada (St. John's, NL, Canada)
Mediapaper; CD-ROM
RelatedThis publication is contained in Harris, J R; (2006). GIS for the earth sciences, Geological Association of Canada, Special Paper vol. 44
File formatpdf
NTS28E; 28F; 28G; 28H; 29; 38E; 38F; 38G; 38H; 39; 48E; 48F; 48G; 48H; 49; 58E; 58F; 58G; 58H; 59; 68E; 68F; 68G; 68H; 69; 78E; 78F; 78G; 78H; 79; 88E; 88F; 88G; 88H; 89; 98E; 98F; 98G; 98H; 99; 120; 340; 560
AreaEllesmere Island; Axel Heiberg Island; Devon Island; Melville Island
Lat/Long WENS-128.0000 -56.0000 84.0000 74.0000
Subjectsmathematical and computational geology; mineralogy; statistical analyses; statistical analysis; statistical methods; statistics; digital log data; remote sensing; mineral exploration; arctic geology; arctic expeditions; mapping techniques; computer mapping; mineral potential
Illustrationsschematic diagrams; location maps; tables
ProgramNSERC Natural Sciences and Engineering Research Council of Canada
ProgramCanada-Northwest Territories Mineral Initiatives, 1991-1996
ProgramMineral and Energy Resource Assessment (MERA)
AbstractData-driven statistical methods used in Mineral Potential Mapping (MPM), such as weights of evidence (WofE), are usually constrained to study areas where there is a sufficient number of known mineral occurrences, complemented by multi-thematic geoscience datasets. However, vast geographical areas remain deficient of this quality and quantity of data; areas for which MPMs are required for regional economic and land-use planning, and mineral exploration. In Canada, such areas of data deficiency constitute over 70% of the land area, including the Canadian High Arctic and other less explored frontier regions. Requirements often call for MPM at multiple scales, and for different commodities and deposit types. Resource geologists are constrained by data deficiency, and further challenged to adequately accommodate 'uncertainty' in the presentation of results, with a presentation style that is consistent across scales, and concisely inform-ative for multi-disciplinary audiences.
A knowledge-driven, 'modified' fuzzy logic method is presented for MPM at multiple scales using only geological maps (as data) and mineral deposit criteria (as knowledge). Previous applications of fuzzy logic use a 'base 0' approach that restricts application to multi-scale mapping, and conflates areas with rankings of low potential with areas of missing data. This modified method uses a 'base 0.5' approach as an uncertainty 'hinge line' upon which Fuzzy Membership Values may diverge toward the pure end members (where 0=No, and 1=Yes) with increasing certainty depending on the data and knowledge available in a variety of geographical scales. A mock WofE example is used to demonstrate how this 'possibilistic' knowledge-driven method is empirically consistent with the 'probabilistic' data-driven approach. The method is demonstrated using an application mapping MVT Pb-Zn potential on Bathurst Island, Nunavut, and surrounding areas, at four scales of representation, using different geological maps. This illustrates the use of fuzzy logic to create MPM in an objective manner that also permits review and iterative modification of the logical steps taken, using different model criteria and assumptions