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TitreGold mineralization in the Cantung W-skarn deposit, Northwest Territories: an examination of distribution, mineralogy, and petrogenesis
TéléchargerTéléchargement (publication entière)
AuteurPalmer, E M; McFarlane, C R M; Lentz, D R; Falck, H
SourceTGI 4 - intrusion related mineralisation project: New vectors to buried porphyry-style mineralisation; par Rogers, N (éd.); Commission géologique du Canada, Dossier public 7843, 2015 p. 415-428, (Accès ouvert)
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 contenue dans Rogers, N; (2015). TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation, Commission géologique du Canada, Dossier public 7843
Référence reliéeCette publication est reliée Chapman, J B; (2014). Mineralogy and chemistry of tourmaline in the Woodjam porphyry deposits, British Columbia, L'Association géologique du Canada-L'Association minéralogique du Canada, Réunion annuelle conjointe, Recueil des résumés vol. 37
ProvinceTerritoires du Nord-Ouest
Lat/Long OENS-128.0000 -126.0000 61.0000 60.0000
Sujetsgisements porphyriques; cuivre porphyrique; prospection minière; minéralisation; altération; tungstène; molybdène; or; gîtes de skarn; pétrogenèse; pétrographie; Mine Cantung ; géologie économique; minéralogie
Illustrationslocation maps; photographs; plots; photomicrographs; plots
ProgrammeInitiative géoscientifique ciblée (IGC-4), Étude des gîtes porphyriques
Diffusé2015 06 11
Résumé(disponible en anglais seulement)
The Cantung mine is a world-class W-skarn deposit; it is located just east of the Yukon border in the Selwyn Mountain Range of the Northwest Territories. The deposit area is within the southern extent of the polymetallic Tintina Gold Belt, which has many notable intrusion-related Au deposits. The extensive W skarns at Cantung were developed by hydrothermal fluids that, based on earlier research, were determined to be predominately supercritical magmatic brines with homogenization temperatures ranging from 270-500°C. Mineralization is composed of calcic exoskarn replacement of a clean limestone and lower grade replacements in a calc- silicate/chert unit; these occur in both the operating open pit and underground mine (the E Zone). The main sulphide identified petrographically is pyrrhotite, which is abundant in all skarn facies. Scheelite and chalcopyrite are dominant and there is locally abundant sphalerite. Native Bi exhibits textures indicative of forming later than the silicate assemblage in the paragenetic sequence, and it is decorated by bismuthinite, Bi tellurides, Ag tellurides, and Bi selenides. Tungsten and Cu are the main mine products, but the Au potential of the deposit merits further investigation.
This study characterized the distribution, mineralogy, and petrogenesis of Au mineralization by examining five skarn samples with bulk rock Au assay values >0.5 ppm taken from the E Zone. No free gold or electrum were identified petrographically or by SEM and FEG- SEM analyses. A positive correlation (Spearman's Rank, r') of Au with Bi (0.76), Ag (0.70), Fe (0.64), Cu (0.64), and Mo (0.60) was identified using the bulk rock geochemical data (n = 48). The strong correlation between Bi and Au is suggestive of a liquid bismuth collector mechanism for Au enrichment. However, LA ICP-MS analysis of native Bi and Bi alloys failed to reveal significant Au predicted by the liquid bismuth collector model. In contrast, the highest Au concentration was encountered in hessite (Ag2Te) and other tellurides. Nano-inclusions within chalcopyrite and silicate minerals were also investigated using FEGSEM for their Au content, but their composition consisted of native Bi. The decoration of native Bi by bismuthinite, Bi tellurides, Ag tellurides, and Bi selenides provides evidence for a late stage S-, Ag-, and Te-rich fluid. This fluid is thought to have remobilized the Au and deposited it as lattice bound invisible Au within the tellurides. This new data constrains Au exploration targets at Cantung to areas of altered skarn or where there is a presence of telluride minerals.