| Title | Mineralogy and spectral signature of reactive gossans, Victoria Island, NT, Canada |
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| Author | Percival, J B ;
Williamson, M -C |
| Source | Applied Clay Science vol. 119, 2015 p. 431-440, https://doi.org/10.1016/j.clay.2015.05.026 |
| Image |  |
| Year | 2015 |
| Alt Series | Earth Sciences Sector, Contribution Series 20150091 |
| Publisher | Elsevier BV |
| Document | serial |
| Lang. | English |
| Media | on-line; digital |
| File format | pdf |
| Province | Northwest Territories; Nunavut |
| NTS | 87H/04; 87H/06 |
| Area | Victoria Island; Minto Inlier; Gossan Hill |
| Lat/Long WENS | -116.0000 -115.6667 71.2750 71.2000 |
| Lat/Long WENS | -114.5833 -114.5833 71.4000 71.3333 |
| Subjects | mineralogy; surficial geology/geomorphology; gossans; analytical methods; x-ray diffraction; spectrometric analyses; glacial deposits; permafrost; freezing ground; ground ice; mine waste products; x-ray
diffraction; mass wasting; erosion; Quaternary |
| Illustrations | location maps; photographs; tables; spectra |
| Program | Environmental Geoscience Tools for environmental impacts and adaptation for metal mining |
| Program | GEM: Geo-mapping for Energy and Minerals PGE/Base Metals - Victoria Island (NWT and Nunavut) |
| Released | 2016 01 01 |
| Abstract | Gossans resulting from the oxidation of sulphide-rich bedrock occur sporadically across Canada, and these features are routinely indicated on geological maps published by the Geological Survey of Canada
(GSC). In the Canadian Arctic Islands, some gossans display reactive zones in permafrost characterized by specific textures and mineralogical facies. In poorly-vegetated areas of the High Arctic, gossans can easily be detected on highresolution
satellite imagery. However, the mechanisms leading to their formation are poorly known. For this study, two reactive gossans located in the early Neoproterozoic Minto Inlier of Victoria Island, Northwest Territories, were investigated to determine if
the deposits constitute (1) analogues of mine waste in permafrost and (2) vectors to economic resources. Mineralogy was determined in situ using a portable spectroradiometer, with follow-up laboratory measurements. Site 1, Gossan Hill, is a 75-m
topographic high capped by a poorly consolidated, rust-coloured layer overlying pyrite-rich sands, and resembles a classic gossan. Site 2, Gossan Sill, underlies a mineralized gabbroic sill consisting of sulphide-rich veins and pods but appears to be
inverted morphologically. Visible-Near Infrared-Short Wave Infrared spectral analyses of surficial materials at Gossan Hill indicate gypsum, goethite and jarosite, and X-ray diffraction (XRD) confirms their presence as well as quartz, illite and
feldspar. At Sill Gossan, spectral analyses show gypsum and jarosite; XRD indicates variable amounts of goethite, hematite, pyrite, chlorite, calcite and feldspar. The positive relief and presence of concentric alteration zones at Gossan Hill suggest
that cryogenic processes, typical of Arctic regions, are active. Water becomes expelled during the freezing cycle forcing material outwards and along with oxidation of the sulphides, forms variably coloured zones in gossanous material. The inverted
stratigraphy at Sill Gossan is more problematic. Constant weathering and mass wasting from the overlying sill and pyrite-rich breccia provide fresh pyrite to the gossan on a regular (seasonal) basis. |
| Summary | (Plain Language Summary, not published)
This paper presents the results of a mineralogical study of two gossans discovered on Victoria Island, NT. Gossans that react with permafrost constitute
analogues of mine wastes that could be generated from a mine in this sensitive environment. In addition, gossans are studied as potential vectors for mineral deposits. The paper presents the results of detailed mineralogical analyses of surficial
deposits collected from these gossans that were obtained using infrared spectroscopy measurements combined with X-ray diffraction analysis. |
| GEOSCAN ID | 296603 |
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