| Title | Application 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 |
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| Author | Laakso, K; Rivard, B; Peter, J M ; White, H P; Maloley, M; Harris, J; Rogge,
D |
| Source | Economic 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 |
| Image |  |
| Year | 2015 |
| Alt Series | Earth Sciences Sector, Contribution Series 20140146 |
| Publisher | Society of Economic Geologists |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf |
| Province | Nunavut |
| NTS | 86H/09 |
| Area | Izok Lake |
| Lat/Long WENS | -112.5000 -112.0000 65.7500 65.5000 |
| Subjects | geophysics; metallic minerals; remote sensing; satellite imagery; hydrothermal alteration; analytical methods; mineral deposits; volcanogenic deposits; sulphide deposits; Precambrian |
| Program | Targeted Geoscience Initiative (TGI-4) Volcanogenic Massive Sulfide Ore Systems |
| Released | 2015 04 15 |
| Abstract | We 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 ID | 295054 |
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