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TitleApplication of airborne, laboratory, and field hyperspectral methods to mineral exploration in the Canadian Arctic: recognition and characterization of volcanogenic massive sulfide-associated hydrothermal alteration in the Izok Lake Deposit area, Nunavut, Canada
AuthorLaakso, K; Rivard, B; Peter, J M; White, H P; Maloley, M; Harris, J; Rogge, D
SourceEconomic geology and the bulletin of the Society of Economic Geologists vol. 110, no. 4, 2015 p. 925-941, https://doi.org/10.2113/econgeo.110.4.925
Year2015
Alt SeriesEarth Sciences Sector, Contribution Series 20140146
PublisherSociety of Economic Geologists
Documentserial
Lang.English
Mediapaper; digital; on-line
File formatpdf
ProvinceNunavut
NTS86H/09
AreaIzok Lake
Lat/Long WENS-112.5000 -112.0000 65.7500 65.5000
Subjectsgeophysics; metallic minerals; remote sensing; satellite imagery; hydrothermal alteration; analytical methods; mineral deposits; volcanogenic deposits; sulphide deposits; hyperspectral imagery; Precambrian
ProgramVolcanogenic Massive Sulfide Ore Systems, Targeted Geoscience Initiative (TGI-4)
Released2015 04 15
AbstractWe have investigated the application of ground, laboratory and airborne optical remote sensing methods for the detection of hydrothermal alteration zones associated with volcanogenic massive sulfide (VMS) deposits using the Izok Lake deposit in Nunavut, Canada as a test case. This bimodal-felsic Zn-Cu-Pb-Ag deposit is located above the tree line in a subarctic environment where lichens are the dominant cryptogamic species on rocks. The deposit is hosted by felsic, intermediate and mafic metavolcanics, and derived metasedimentary rocks. The immediate host rhyolitic rocks have been hydrothermally altered and contain biotite, chlorite and white micas as alteration (and metamorphosed equivalent) minerals. These minerals have spectral Al-OH and Fe-OH absorption features in the short-wave infrared wavelength region that display wavelength shifts that are documented to be due chemical compositional changes. Our results indicate that the Fe-OH absorption feature wavelength positions (hull quotient minima) of biotite/chlorite, extracted from ground spectra, shift systematically toward longer wavelengths in the vicinity of the ore deposit. The Al-OH absorption feature wavelengths of white mica minerals do not reveal any such trends, but a zone of phengitic muscovite is delineated in areas proximal to the deposit using both the ground and airborne spectra. These observations indicate that spatial variations in the alteration minerals can be detected based on the spectral shifts of an Al-OH and Fe-OH absorption features by means of hyperspectral ground, airborne and spaceborne sensors in the subarctic regions despite the common presence of abundant lichens on rock outcrops. These spectral variations can be used to vector toward previously unrecognized mineralization.
Summary(Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. This paper details the results of an investigation into the application of optical reflectance spectrometry for the exploration for base-metal (Cu, Pb, Zn) deposits in the Canadian Arctic. The use of sensors mounted on an airplane and on a field-portable instrument were investigated. Both sensors provided data that revealed the presence of (and characterization of)hydrothermally altered rocks associated with the mineralization. These methods have the potential to be more "green" and benign at the early stages of exploration than other methods currently being employed.
GEOSCAN ID295054