| Titre | Geology, structural evolution, and hydrothermal alteration of the Island gold deposit, Michipicoten greenstone belt, Ontario |
| Télécharger | Téléchargement (publication entière) |
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| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Ciufo, T J; Jellicoe, K; Yakymchuk, C; Lin, S; Mercier-Langevin, P; Wodicka, N |
| Source | Targeted Geoscience Initiative 5: contributions to the understanding of Canadian gold systems; par Mercier-Langevin, P (éd.); Lawley, C J M (éd.); Castonguay, S (éd.); Commission géologique du Canada, Dossier public 8712, 2020 p. 143-156, https://doi.org/10.4095/323671  Accès ouvert |
| Année | 2020 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/323671 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans Targeted
Geoscience Initiative 5: contributions to the understanding of Canadian gold systems |
| Formats | pdf |
| Province | Ontario |
| SNRC | 42C/08 |
| Région | Goudreau-Lochalsh Gold District; Dubreuilville; Wawa |
| Lat/Long OENS | -84.4833 -84.3167 48.3500 48.2667 |
| Sujets | gisements minéraux; or; prospection minière; directives d'exploration; genèse des minerais; contrôles des minerais; ceintures de roche verte; dynamique des fluides; antécédents tectoniques;
minéralisation; altération hydrothermale; métamorphisme; déformation; faciès à schiste vert; foliation; clivage; fluage; intrusions; filons rocheux; plutons; filons de quartz; veinules; tourmaline; cisaillement; déformation; roches hôtes; géologie du
substratum rocheux; caractéristiques structurales; plis; structures anticlinale; anticlinaux; synformes; failles; failles inverses; lithologie; roches ignées; roches volcaniques; volcanoclastique; dacites; roches intrusives; gabbros; tonalites;
trondhjémites; diorites; monzodiorites; roches intrusives felsiques; roches intrusives mafiques; diabases; roches sédimentaires; formations ferrifères; analyses structurales; tendances structurelles; analyses géométriques; rapports sur le terrain;
analyses texturales; métallogénie; analyses pétrographiques; datation radiométrique; datation au uranium-plomb; datations au zircon; Archéen; Province de Superior ; Formation de fer de Michipicoten; géologie économique; tectonique; géologie
structurale; pétrologie ignée et métamorphique; minéralogie; géochronologie; Sciences et technologie; Nature et environnement; Précambrien |
| Illustrations | cartes de localisation; cartes géolscientiques généralisées; coupes schématiques transversales; projections stéréographiques équivalentes; photographies; photomicrographies; graphiques; diagrammes;
graphique à barres; blocs-diagrammes |
| Programme | Initiative géoscientifique ciblée (IGC-5) Systèmes minéralisés aurifères |
| Diffusé | 2020 06 11 |
| Résumé | (disponible en anglais seulement)
The Archean Island Gold deposit is situated in the Michipicoten greenstone belt within the Abitibi-Wawa subprovince. Gold mineralization is hosted in dacitic
volcanic and volcaniclastic rocks, gabbro, and a tonalite-trondhjemite body (Webb Lake stock) within the southern domain of the east-west-trending Goudreau Lake deformation zone. The area is highly prospective, however, the controls on high-grade
mineralization and the timing of events in the Michipicoten belt remain to be firmly established and compared with major gold systems of the southern Abitibi belt.
Several phases of deformation have affected the host rocks. The first deformation
(D1) event produced regional-scale folds. The second deformation (D2) event resulted in camp-scale folds (F2), a steep axial planar foliation (S2), regional greenschist-grade metamorphism, and the formation of the Goudreau Lake deformation zone. The
third deformation (D3) event is expressed by brittle reverse faults, camp- to outcrop-scale folds (F3), and a weakly developed axial planar (S3) cleavage.
Gold mineralization in the main Island Gold ore zones was emplaced along the Goudreau Lake
deformation zone during the D2 deformation event. The Goudreau Lake deformation zone is inferred to be the major conduit that focused the gold-bearing fluids. The main ore zones dip steeply towards the south and consist of shear-hosted laminated
quartz veins (V1) and associated extensional veinlets (V2). This V1-V2 veining is sub-parallel to the S2 foliation and concentrated in the strain shadow of the pre-mineralization Webb Lake stock during D2 north-side-up, sinistral transpression.
Shallowly dipping, extensional quartz veins (VGD) also host economic gold mineralization in the Goudreau Zone, which is located north of the main zones. The VGD and V1-V2 veins are cut by extensional quartz veins (V3) that formed during the third
deformation (D3) event in areas of high competency contrast. Post-mineralization tourmaline-quartz veins (V4) locally overprint the V3 veins and pre-existing structures.
Alteration envelopes associated with auriferous veining at the Island Gold
deposit range from the centimetre to metre scale and are enriched in Au, K2O, Rb, S, and Te, and depleted in Na2O. Alteration minerals associated with ore zones generally include biotite, Ca-Mg-Fe carbonates, chlorite, plagioclase, quartz, sulphides
(pyrite±pyrrhotite±chalcopyrite), and white mica (muscovite±phengite). Weak alteration associated with the late V3 non-auriferous veins is variable and local.
The upper and lower absolute limits on the timing of gold mineralization are constrained
by the U-Pb zircon ages of the mineralized Webb Lake stock (2724.1 ± 4.3 Ma) and the post-mineralization silica-poor diorite-monzodiorite (I2M) dykes (2672.2 ± 3.5 Ma). The youngest detrital zircon ages from overlying Doré sedimentary rocks, which
were affected by syn-D2 greenschist-facies metamorphism, further constrain the maximum age limit for the timing of gold mineralization to 2680 ± 3 Ma. This timing (2680 ± 3 Ma to 2672.2 ± 3.5 Ma) falls within the typical age range for gold deposits
in greenstone belts of the Superior Province. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Le principal objectif de la phase 5 (2015-2020) du programme de l'Initiative géoscientifique ciblée (IGC) de Ressources naturelles Canada et de
la Commission géologique du Canada était de générer de nouvelles connaissances, méthodologies et modèles pour améliorer la capacité de l'industrie de l'exploration à détecter les gisements enfouis. Ce volume de synthèse contient 20 articles
individuels qui traitent des caractéristiques des gisements aurifères à l'échelle du craton à celle du gisement, ainsi que certains documents reliés au projet Gold de l'IGC-5. |
| GEOSCAN ID | 323671 |
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