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TitleThe Ferguson Lake deposit: an example of Ni-Cu-Co-PGE mineralization in a back-arc basin setting?
AuthorAcosta-Góngora, P; Pehrsson, S J; Sandeman, H; Martel, E; Peterson, T
SourceCanadian Journal of Earth Sciences vol. 55, no. 8, 2018 p. 958-979,
Alt SeriesNatural Resources Canada, Contribution Series 20170289
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html; tif
NTS65I/09; 65I/10; 65I/11; 65I/14; 65I/15; 65I/16
AreaFerguson Lake
Lat/Long WENS -97.5000 -96.0000 63.0000 62.5000
Subjectseconomic geology; tectonics; geochemistry; mineral deposits; mineral potential; nickel; copper; cobalt; sulphide deposits; mineralization; mineral exploration; exploration guidelines; tectonic setting; geodynamics; mid-ocean ridges; basins; greenstone belts; metamorphism; intrusions; metamorphic facies; amphibolite facies; whole rock geochemistry; trace element analyses; major element analyses; geochemical anomalies; niobium geochemistry; ytterbium geochemistry; thorium geochemistry; zirconium geochemistry; magnesium geochemistry; metasomatism; bedrock geology; lithology; ultramafic rocks; igneous rocks; intrusive rocks; tonalites; granodiorites; granites; diorites; monzo-granites; syenites; gabbros; hornblendites; volcanic rocks; volcaniclastics; basalts; metamorphic rocks; metavolcanic rocks; metasedimentary rocks; psammites; structural features; faults; antiforms; synforms; shear zones; faults; petrographic analyses; petrogenesis; Archean; Ferguson Lake Deposit; Ferguson Lake Igneous Complex; Yathkyed Greenstone Belt; Chesterfield Block; Churchill Province; MacQuoid Greenstone Belt; Hearne Craton; Rae Craton; Hudson Granite; Suluk Occurrence; platinum group elements; extension; back-arc basins; massive sulphide deposits; rare earth element analyses; mid-ocean ridge basalts (MORB); silicon dioxide; Precambrian; Proterozoic
Illustrationslocation maps; geoscientific sketch maps; schematic representations; photographs; photomicrographs; tables; geochemical plots; ternary diagrams
ProgramSouth Rae Province Bedrock/Surficial geology, GEM2: Geo-mapping for Energy and Minerals
Released2018 05 02
AbstractThe world's largest Ni-Cu-Platinum group element (PGE) deposits are dominantly hosted by ultramafic rocks within continental extensional settings (e.g., Raglan, Voisey's Bay), resulting in a focus on exploration in similar geodynamic settings. Consequently, the economic potential of other extensional tectonic environments, such as ocean ridges and back-arc basins, may be underestimated. In the northeastern portion of the ca. 2.7 Ga Yathkyed greenstone belt of the Chesterfield block (western Churchill Province, Canada), the Ni-Cu-Co-PGE Ferguson Lake deposit is hosted by >2.6 Ga hornblenditic to gabbroic rocks of the Ferguson Lake Igneous Complex (FLIC), which is metamorphosed up to amphibolitic facies. The FLIC has a basaltic composition (Mg# = 31-72), flat to slightly negatively sloped normalized trace element patterns (La/Yb(PM) = 0.7-3.5), and negative Zr, Ti, and Nb anomalies. The FLIC rocks are geochemically similar to the 2.7 Ga back-arc basin tholeiitic basalts from the adjacent Yathkyed and MacQuoid greenstone belts (Mg# = 30-67; La/Yb(PM) = 0.3-3.0), but the Ferguson Lake intrusions appear to be more crustally contaminated. We interpret the FLIC to have formed in an equivalent back-arc basin setting. This geodynamic setting is rare for the formation of Ni-Cu-PGE occurrences, and only few examples of this tectonic environment (or variations of it, e.g., rifted back-arc) are found in other Proterozoic and Archean sequences (e.g., Lorraine deposit, Quebec). We suggest that back-arc basin-derived mafic rocks within the Yathkyed and other Neoarchean greenstone belts of the Chesterfield block (MacQuoid and Angikuni) could represent important targets for future mineral exploration.
Summary(Plain Language Summary, not published)
This work documents the geochemical characteristics of the gabbroic intrusion host to the Ferguson Lake Ni-Cu-Co-PGE mineralization, in the Nunavut Territory. This study suggests that the Ferguson lake was formed in a back-arc basin setting, similar to that of the neighboring 2.7 Ga Yathkyed and MacQuoid greenstone belts. The main implications are: 1) the occurrence of Ni-Cu-PGE mineralization in a back-arc basin environment, which is rare in the geological record and 2) The potential for Ni-Cu-PGE mineralization in similar gabbroic rocks within the Yathkyed and MacQuoid belts.