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TitleRevisiting the magmatic Ni-Cu-PGE prospectivity of the High Arctic LIP, Nunavut, Canada
AuthorSaumur, B M; Williamson, M -CORCID logo; Bédard, J H
SourceGeoconvention 2020, abstract archive; 2020 p. 1 Open Access logo Open Access
LinksOnline - En ligne
Image
Year2020
Alt SeriesNatural Resources Canada, Contribution Series 20190650
PublisherGeoConvention 2020
MeetingGeoconvention 2020; September 13-15, 2020
DocumentWeb site
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceNunavut
NTS49F; 49G; 59E; 59F; 59G; 59H; 340B; 340C; 560A; 560D
AreaQueen Elizabeth Islands; Ellesmere Island; Wootton Peninsula; Axel Heiberg Island; Middle Fiord
Lat/Long WENS -96.0000 -84.0000 81.5000 78.0000
Subjectseconomic geology; geochemistry; structural geology; Science and Technology; Nature and Environment; mineral deposits; mineral potential; magmatic deposits; nickel; copper; intrusions; sills; bedrock geology; lithology; igneous rocks; mafic rocks; intrusive rocks; diabases; gabbros; volcanic rocks; basalts; structural features; fault zones; High Arctic Large Igneous Province (HALIP); Schei Sills; Stolz Thrust Zone; Strand Fiord Formation; platinum group elements
ProgramGEM2: Geo-mapping for Energy and Minerals, Western Arctic, Tertiary Onshore, Smoking Hills
Released2020 09 01
Abstract(Summary)
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.
Summary(Plain Language Summary, not published)
In this presentation, we highlight the results of geochemical studies carried out under the Geo-mapping for Energy & Minerals Program (GEM-2). The objective of the study was to re-examine the Ni-Cu-PGE potential of the High Arctic Large Igneous Province (HALIP) with a focus on regional mapping and sampling on Axel Heiberg Island and Northern Ellesmere Island. Our data suggest that the Middle Fiord volcanic-intrusive complex and the Schei Sills emplaced during the initial pulse of the HALIP (120 Ma) constitute the most prospective areas.
GEOSCAN ID322190

 
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