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TitleShort-Wave Infrared Spectral and Geochemical Characteristics of Hydrothermal Alteration at the Archean Izok Lake Zn-Cu-Pb-Ag Volcanogenic Massive Sulfide Deposit, Nunavut, Canada: Application in Exploration Target Vectoring
AuthorLaakso, K; Rivard, B; Peter, J M
SourceEconomic geology and the bulletin of the Society of Economic Geologists vol. 111, 5, 2016 p. 1223-1239,
Alt SeriesEarth Sciences Sector, Contribution Series 20150300
PublisherSociety of Economic Geologists
Mediapaper; on-line; digital
File formatpdf
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
Illustrationslocation maps; graphs; histograms
ProgramTargeted Geoscience Initiative (TGI-4), Volcanogenic Massive Sulfide Ore Systems
Released2016 05 23
AbstractShort-wave infrared (SWIR) field and laboratory spectra were used to identify and characterize hydrothermal alteration mineral chemical variability in host rocks proximal to the Izok Lake Zn-Cu-Pb-Ag volcanogenic massive sulfide (VMS) deposit in Nunavut, Canada. The deposit is hosted within a sequence of predominantly felsic pyroclastic rocks of Archean age that are regionally metamorphosed to amphibolite facies. These rocks are characterized by the muscovite-biotite-sillimanite and chlorite-biotite-cordierite mineral suite. Proximal to the deposit, white micas are Al rich to potassic muscovite, and the biotite and chlorite are Mg rich. In areas that are
immediately outboard of the proximal alteration zones, rocks are altered to Al-poor muscovite and intermediate to Fe-rich biotite and chlorite. Outboard of this, distal areas are characterized by potassic muscovite and Mg-rich biotite and chlorite. The white micas and biotite/chlorite group minerals display considerable variation in their Al-OH and Fe-OH absorption feature wavelength positions. The variations in muscovite and biotite/ chlorite compositions (as determined by the Al-OH and Fe-OH absorption feature wavelength positions) broadly correlate with changes in hydrothermal alteration intensity, as measured by the Ishikawa and chloritecarbonate-
pyrite alteration indices. Our findings suggest that the large-scale alteration intensity trends of the Izok Lake study area can be elucidated using the spectral properties of the hydrothermal alteration minerals.
Summary(Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI) 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 applies so-called hyperspectral short-wave infrared (SWIR; a type of optical reflectance spectrometry), measurements made in the field and laboratory spectroscopy to identify rocks around a base metal deposit in the arctic of Canada. This test case shows that such data can be used in the exploration for base-metal deposits in areas with abundant lichens in Canada's north.