| Titre | Revisiting the magmatic Ni-Cu-PGE prospectivity of the High Arctic LIP, Nunavut, Canada |
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| Auteur | Saumur, B M; Williamson, M -C ; Bédard, J H |
| Source | Geoconvention 2020, abstract archive; 2020 p. 1  Accès
ouvert |
| Liens | Online - En ligne
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| Image |  |
| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190650 |
| Éditeur | GeoConvention 2020 |
| Réunion | Geoconvention 2020; Septembre 13-15, 2020 |
| Document | site Web |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Nunavut |
| SNRC | 49F; 49G; 59E; 59F; 59G; 59H; 340B; 340C; 560A; 560D |
| Région | Îles de la Reine-Élisabeth; île d'Ellesmere; Wootton Peninsula; Axel Heiberg Island; Middle Fiord |
| Lat/Long OENS | -96.0000 -84.0000 81.5000 78.0000 |
| Sujets | gisements minéraux; potentiel minier; gîtes magmatiques; nickel; cuivre; intrusions; filons-couches; géologie du substratum rocheux; lithologie; roches ignées; roches mafiques; roches intrusives;
diabases; gabbros; roches volcaniques; basaltes; caractéristiques structurales; zones de failles; Zone de Stolz Thrust ; Formation de Strand Fiord ; éléments du groupe de platine; géologie économique; géochimie; géologie structurale; Sciences et
technologie; Nature et environnement |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Smoking Hills, géologie tertiaire du territoire de l'ouest de l'Arctique |
| Diffusé | 2020 09 01 |
| Résumé | (Sommaire disponible en anglais seulement)
The Canadian portion of the High Arctic Large Igneous Province (HALIP) ranges in age from ~130 to 80 Ma, and is exposed on Canada's Queen Elizabeth
archipelago, mostly on Axel Heiberg and Ellesmere Islands. A recent mapping initiative under the federal Geo-mapping for Energy & Minerals Program (GEM-2) focused on the regional-scale Ni-Cu-PGE potential of the HALIP, integrating the structure and
architecture of the province with the geochemistry of diabases, gabbros and basalts from intrusive-volcanic complexes. Previous work on the prospectivity of the HALIP concluded that subalkaline mafic units located on Axel Heiberg were more
prospective than younger, mildly alkaline igneous rocks exposed on northern Ellesmere. Further sampling of the province indicates that subalkaline rocks occur on western Ellesmere Island, representing the along-strike continuation of a stratigraphic
sequence along eastern Axel Heiberg Island containing abundant sills, herein known as the Schei Sills (ca. 120 Ma).
Orthomagmatic Ni-Cu-PGE deposits associated with mafic magmas tend to be located within subvolcanic intrusive settings. Also, one
expects geochemical evidence, at the local intrusive complex scale, for chalcophile metal enrichment in some magma pulses while others should show evidence for sulfide saturation and chalcophile element removal, consistent with the formation of a
metal-enriched sulfide liquid somewhere in that system. A ~20 km2 intrusive complex at Middle Fiord (western Axel Heiberg), shows a bimodal distribution of Cu/Zr above and below unity, consistent with sulfide enrichment and removal, respectively. A
similar observation is made at various localities within the Schei Sills. The spatial association of the Schei Sills with the Eocene Stolz thrust zone is noteworthy, since this post-HALIP thrusting uplifted and exposed subvolcanic roots. Absolute
IPGE contents are low throughout the HALIP, but Pt and Pd contents vary among analysed subalkaline rocks; Pt+Pd ranging between 10-30 ppb detected at both Middle Fiord and the Schei Sills are consistent with heightened prospectivity. In contrast,
thick voluminous flood basalts of the 95 Ma Strand Fiord Formation exposed in western Axel Heiberg, although they are subalkaline, exhibit Cu/Zr below 1 and low PPGE contents. Furthermore, olivine phenocrysts exhibit very low Ni contents (<250 ppm)
for moderate Fo compositions (Fo50-30), suggesting that there was very little metal extracted from the mantle source associated with the Strand Fiord Formation. It thus appears that the ca. 120 Ma magmatic event that produced the Schei Sills
generated magmas that are more slightly prospective than those of the ca. 95 Ma event. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Dans cette présentation, nous soulignons les résultats des études géochimiques réalisées dans le cadre du programme de géocartographie de
l'énergie et des minéraux (GEM-2). L'objectif de l'étude était de réexaminer le potentiel en Ni-Cu-ÉGP de la Grande Province Ignée de l'Extrême Arctique (HALIP) en se concentrant sur la cartographie régionale et l'échantillonnage sur l'île Axel
Heiberg et le nord de l'île d'Ellesmere. Nos données indiquent que le complexe volcanique intrusif de Middle Fiord et les filons-couches de Schei mis en place au cours de la phase initiale du HALIP (120 Ma) sont les secteurs les plus
prometteurs. |
| GEOSCAN ID | 322190 |
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