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TitreQuantitative mineralogy of gossans and stream sediments in the High Arctic Large Igneous Province (HALIP) via SEM-MLA: Implications for economic potential
AuteurWilton, D H C; Williamson, M C; McNeil, R J
Séries alt.Ressources naturelles Canada, Contribution externe 20170004
ÉditeurAssociation géologique du Canada
RéunionGAC-MAC 2017 Annual Meeting; Kingston; CA; mai 14-18, 2017
Lang.anglais
Mediapapier; en ligne; numérique
Formatspdf
ProvinceNunavut; Terre-Neuve-et-Labrador
Sujetschapeaux ferrugineux; sulfures; gisements minéraux; diapirs; évaporites; géologie générale; géochimie; minéralogie; Carbonifère; Crétacé
ProgrammeLIP de l'haut-Arctique de l'ouest de l'Arctique, GEM2 : La géocartographie de l'énergie et des minéraux
LiensOnline - En ligne
Résumé(disponible en anglais seulement)
Gossans are a common geological feature of the Canadian North, and Arctic Islands in particular. Due to the lack of archetypal vegetative cover in boreal regions, gossans are a highly visible component of the landscape in tundra areas. Fundamentally, gossans represent highly oxidized surficial or bedrock material, and are most intensely developed on sulphide-rich media. As such, gossans have been used to locate significant mineral deposits in the Canadian North, including the Voisey¿s Bay orthomagmatic Ni-Cu-Co sulphide deposits of Labrador. Since gossans can also be developed on geological materials with sparse or nil sulphide contents, recognition of the parental material to a gossan, and hence discrimination of potentially economically significant gossans, could prove a significant tool for regional mineral potential evaluation. One problem with sampling gossans, however, is that they can be quite thick and/or layered, hence collection of representative material for traditional geochemical and/or petrographic determination of protolithologies can be challenging.

Gossans are a common geological feature of the Canadian North, and of the High Arctic Islands in particular. Due to the lack of archetypal vegetative cover as in boreal regions, gossans are a highly visible component of the landscape in tundra areas. Fundamentally, gossans represent intensely oxidized surficial or bedrock material, and are most intensely developed on sulphide-rich substrate. As such gossans have been used as exploration vectors in the search for significant mineral deposits in the Canadian North, including the Voisey’s Bay orthomagmatic Ni-Cu-Co sulphide deposits of Labrador. Since gossans can also be developed on geological materials with sparse or nil sulphide contents, recognition of the parental material to a gossan, and hence discrimination of potentially economically significant gossans, could prove to be a significant tool for regional mineral potential evaluation. One problem with sampling gossans, however, is that they can be quite thick and/or layered, hence collection of representative material for traditional geochemical and/or petrographic determination of protolithlogy can be difficult.

We used the automated mineral analysis capabilities of the SEM-MLA system to examine: 1) gossans developed on three different lithologies, and 2) stream sediments downstream from the gossan occurrences in the HALIP exposed in western Axel Heiberg Island. The South Fiord study area is underlain by Cretaceous sedimentary rocks intruded by Carboniferous evaporate diapirs (expressed as sulphate domes) and by HALIP intrusive and extrusive igneous rocks. Gossans examined were developed on evaporite, shale-sill and shale-volcanic rock substrates. The different gossans, and in part stream sediments, are readily distinguishable in terms of sulphate, sulphide, and silicate alteration minerals as defined by the SEM-MLA. The technique appears to offer the ability to distinguish gossan protolithogies during regional surveys and thus define economic potential.
Résumé(Résumé en langage clair et simple, non publié)
Ce résumé présente les résultats d 'une étude minéralogique qui intègre des données sur les chapeaux de fer et les sédiments de cours d' eau échantillonnés dans la région de South Fiord, dans la partie ouest de l' île Axel Heiberg au Nunavut. Les auteurs ont appliqué une technique d'analyse automatisée pour déterminer quels types de minéraux-clés sont présents dans les chapeaux de fer et les sédiments de cours d'eau, avec des implications pour le potentiel économique. La technique offre un potentiel comme outil d'exploration minérale pour comparer les gossans et sédiments de cours d¿eau à l¿échelle régionale dans cette partie du Nunavut.
GEOSCAN ID300256