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TitleMorphology of gossans in the Canadian Arctic Islands
AuthorPercival, J B; Williamson, M -C; McNeil, R J; Harris, J
SourceGeological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Abstracts Volume vol. 37, 2014 p. 219 (Open Access)
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20130475
MeetingGeological Association of Canada - Mineralogical Association of Canada Joint Annual Meeting; Fredericton; CA; May 21-23, 2014
File formatpdf
ProvinceNunavut; Northwest Territories
AreaArctic Islands; Victoria Island; Axel Heiberg Island
Subjectssurficial geology/geomorphology; geophysics; gossans; sulphides; sulphide deposits; alteration; remote sensing
ProgramEnvironmental Geoscience, environmental impacts and adaptation in the northern environment
AbstractChemical and physical weathering of bedrock and surficial materials may produce secondary minerals that vector to buried ore deposits. For example, the classic gossan includes a sulphide - depleted and silica - enriched leach cap, underlain by the main gossan zone enriched in Fe - oxides, Fe - oxyhydroxides and other secondary minerals, overlying mineralized bedrock or surficial material containing primary sulphide minerals. Under certain conditions, some of these gossans react with permafrost and provide an analogue for mine wastes in the northern environment. The Arc tic Gossans Activity was supported by the Environmental Geoscience and Geo - Mapping for Energy and Minerals Programs between 2011 and 2014. Over the course of 2 field seasons on Victoria Island, NT, and Axel Heiberg Island, NU, several types of oxide - sulphide gossans were located and sampled. Remarkably, the morphology of these gossans is complex and in some cases, does not match the classic profile described above. The deposits are found within a variety of host rocks that include: volcanic successions, mafic sills, pyritic shale, evaporite diapirs and sulphide chimneys. In most cases, the gossans are associated with mafic intrusive rocks and local faulting. In other cases, there is no direct field evidence of an igneous protolith or nearby fault. In all cases, goethite, jarosite and gypsum predominate. Remote sensing technology has enabled detection of these alteration zones and identification of their inherent mineralogy, at various scales. Ground truthing during mapping, combined with analysis of materials (surficial and at depth) using field portable instruments such as reflectance spectroradiometer, allows rapid and precise detection of key alteration minerals. Follow - up laboratory mineral analysis (XRD/SEM) enabled detailed characterization of these deposits. This presentation will explore the similarities and differences in gossan development in the two study areas. It will demonstrate the need to be systematic with respect to (1) detection (2) classification (3) sampling (4) mineralogy and geo chemistry (5) and (6) integration with regional mapping.
Summary(Plain Language Summary, not published)
This abstract describes the morphological characteristics (shape, size, stratigraphy, composition) of gossans located in central Victoria Island, Northwest Territories, and western Axel Heiberg Island, Nunavut. The presentation will summarize the field and laboratory protocols that enabled the classification of several types of gossans discovered in the study areas.