| Titre | Remote predictive mapping of gossans in the Muskox feeder dyke, Nunavut |
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| Auteur | Bethell, E M; Williamson, M -C ; Brassard, É |
| Source | Geological Association of Canada, Program and Abstracts 2023 p. 1 |
| Image |  |
| Année | 2023 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20220672 |
| Éditeur | Association géologique du Canada |
| Réunion | Joint Annual Meeting of the Geological Association of Canada, Mineralogical Association of Canada, and Society for Geology Applied to Mineral Deposits; Sudbury; CA; mai 24-27, 2023 |
| Document | publication en série |
| Lang. | anglais |
| Media | papier; numérique; en ligne |
| Formats | pdf |
| Province | Nunavut |
| SNRC | 86J/07; 86J/10; 86J/11; 86J/14; 86N/03 |
| Lat/Long OENS | -115.5000 -114.5000 67.2500 66.2500 |
| Sujets | filons rocheux; intrusions; roches intrusives mafiques; chapeaux ferrugineux; analyses spectrales; Intrusion de Muskox |
| Programme | GEM-GéoNord : La géocartographie de l'énergie et des minéraux Coordination du programme GEM |
| Diffusé | 2023 05 01 |
| Résumé | (disponible en anglais seulement)
Geological mapping in Canada's North often includes analysis of satellite imagery as part of remote predictive mapping (RPM) in advance of fieldwork. In large
igneous provinces (LIPs), it is possible to resolve smaller features of the local geology using imagery with sufficiently high spatial resolution (0.5-5 m) to reconstruct the magmatic history of the region. Gossans that form from weathering of
sulphide and oxide minerals in the host bedrock can be detected in visible-near-infrared (VNIR) and short-wave infrared (SWIR) imagery. Most gossans form relatively small surface footprints but the distinctive yellow-orange colour of the oxide cap
make them easily recognizable on PRISMA and WorldView images, for example, depending on the size of the deposit. The Muskox Intrusion is a layered mafic-ultramafic intrusion located 90 km southeast of Kugluktuk, near the Coronation Gulf, that is part
of the 1.27 Ga Mackenzie LIP. The intrusion was discovered by the Canadian Nickel Company in 1956 during an aerial reconnaissance survey that detected sulphide-rich gossans exposed along the footwall contacts. A recent study of the geomorphic
attributes and spectral signatures of Baffin Island gossans completed in 2021 demonstrated the validity of using RPM to detect gossans on a regional scale. Here we use the same approach to investigate the gossans developed on a local scale along the
Muskox feeder dyke in the Spider-Eider Lakes (SEL) area. The first step in our analysis is to delimit the bedrock exposures along the feeder dyke using Esri World Imagery and available geological maps. We then test several image processing methods to
map gossans that were documented in the published literature, including those mapped in the SEL area at a scale of 1:10,000. WorldView-2 images (0.5 m/pixel) allow more accurate observations of the deposits at a spatial resolution 2.5 times better
than provided by Esri World Imagery. Our goals are: (1) to determine the spectral features of the gossans on a local scale; (2) to subsequently extend the RPM approach to the entire feeder dyke area (400 km2); and, (3) to determine if this approach
is applicable to gossans mapped in areas south of the Muskox Intrusion. The anticipated result is a first order classification of the SEL gossans based on geomorphic attributes and spectral signatures that is integrated with published geochemical
data on both fertile and barren gossans. This approach provides a first order exploration tool in areas with high Ni-Cu-PGE potential, such as the Muskox Intrusion. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Les chapeaux de fer sont des dépôts en surface ou des zones riches en fer qui se forment à la suite de l'altération des sulfures massifs
présents dans les roches encaissantes. La plupart des chapeaux de fer sont de petite taille (de quelques dizaines de mètres à moins de 1 ou 2 km de long) et nous indiquons généralement leur présence par un seul point sur les cartes géologiques. Dans
cette présentation, nous décrivons le potentiel de l'utilisation d'images satellites pour identifier et cartographier les chapeaux de fer affleurant le long du dyke d'alimentation de l'intrusion de Muskox. Notre approche systématique de la
télécartographie prédictive des chapeaux de fer affleurant dans une cible économique de classe mondiale telle que l'intrusion de Muskox ajoute un outil d'exploration de premier ordre qui peut être intégré à aux données minéralogiques et
géochimiques. |
| GEOSCAN ID | 331755 |
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