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TitreIndicator mineral signatures of magmatic Ni-Cu deposits, Thompson Nickel Belt, Manitoba: Part 2 - till data
AuteurMcClenaghan, M B; Kjarsgaard, I M; Averill, S A; Layton-Matthews, D; Crabtree, D; Matile, G; McMartin, I; Pyne, M
SourceCommission géologique du Canada, Dossier public 7200, 2013, 148 pages,
LiensCanadian Database of Geochemical Surveys, downloadable files
LiensBanque de données de levés géochimiques du Canada, fichiers téléchargeables
ÉditeurRessources naturelles Canada
Documentdossier public
Mediaen ligne; numérique
Référence reliéeCette publication est reliée McClenaghan, M B; Kjarsgaard, I M; Averill, S A; Layton-Matthews, D; Crabtree, D; Matile, G; (2012). Indicator mineral signatures of magmatic Ni-Cu deposits, Thompson Nickel Belt, Manitoba: Part 1 - bedrock data, Commission géologique du Canada, Dossier public 6766
Formatspdf; rtf; xls
SNRC63I; 63J; 63O; 63P
Lat/Long OENS-100.0000 -96.0000 56.0000 54.0000
Sujetsdépôts glaciaires; elements glaciaires; topographie glaciaire; tills; analyses de till; géochimie du till; écoulement glaciaire; directions des mouvements de la glace; directions du transport de la glace; éléments d'indice; lithologie des galets; géologie du substratum rocheux; analyses par microsonde électronique; analyses minéralogiques; gîtes minéralogiques; pentlandite; sperrylite; chalcopyrite; pyrrhotite; arsénopyrite; pyrite; gîtes sulfureux; or; chromite; spinelle; ilménite; diopside; olivine; gîtes magmatiques; minéralisation; roches ultramafiques; lithologie; Ceinture de Thompson Nickel ; stratigraphie; géologie des dépôts meubles/géomorphologie; Cénozoïque; Quaternaire; Protérozoïque; Précambrien
Illustrationslocation maps; photographs; flow charts; tables; plots; ternary diagrams
Bibliothèque de Ressources naturelles Canada - Ottawa (Sciences de la Terre)
ProgrammeÉtude des gîtes porphyriques, Initiative géoscientifique ciblée (IGC-4)
Diffusé2013 06 10
Résumé(disponible en anglais seulement)
The Geological Survey of Canada (GSC) conducted an indicator mineral study around the komatiite-associated Ni-Cu deposits in the northern Thompson Nickel Belt, northern Manitoba, to document the indicator mineral signatures of the Ni-Cu deposits. Samples used in this study include archived till heavy mineral concentrates from 1996, till and bedrock samples collected in 2005 and 2006, and till samples collected in 2007 as part of another GSC study. The Laurentide Ice Sheet flowed across the Thompson Nickel Belt southwestward, and subsequently westward, and striations from both ice-flow events are readily apparent on outcrops along the Belt. Till samples were collected to evaluate glacial dispersal along both ice-flow trends. Till and bedrock samples were processed to recover heavy (specific gravity>3.2) mineral concentrates. Potential indicator minerals picked from heavy mineral concentrates included Cr-diopside, olivine, chromite, spinel, gahnite, rutile, pink corundum, and sapphirine, as well as metallic minerals such as pyrrhotite, pentlandite, chalcopyrite, pyrite, arsenopyrite, gold, and sperrylite.
Elevated chromite abundances combined with the presence of Ni-Cu sulphide minerals are strong indicators of potential magmatic Ni-Cu mineralization in till down ice of the Ni-Cu deposits in the Belt. Chalcopyrite and sperrylite are the most useful metallic indicator minerals as they are the most likely to survive glacial transport and postglacial weathering. Elevated Zn content (>2 wt.% ZnO) in chromite is only found in strongly mineralized rocks and is the strongest indicator for mineralization other than the actual ore minerals. The Zn content in chromite from Ni-deposits might be considerabley lower in regions with lower metamorphic grade and thus this feature does not have universal application. The distribution of Cr-diopside, olivine, enstatite, and chromite are similar and are most abundant just east of the Thompson Nickel Belt, at the Thompson deposit and south of the Pipe deposit. Their mafic Cr- or Ni-rich compositions reflect the abundance of ultramafic rocks in the area. Chemical variations in Cr-diopside (higher Cr, Na) and olivine (variable Ni) and the occurrence of high-grade metamorphic minerals, such as corundum, sapphirine, rutile, and spinel, reflect the higher metamorphic grades in certain areas, rather than presence or absence of mineralization. Exploration along the Thompson Nickel Belt and in the surrounding terranes should consider both the older southwest and younger westward ice-flow events when interpreting and following up till indicator mineral results.