| Titre | Fluid inclusion and stable isotope evidence for mixing of magmatic - hydrothermal fluids with meteoric water in vein-type Cu-Au-Bi deposits, southern New Brunswick, Canada |
| Télécharger | Téléchargements |
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| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Hanley, J J; Tweedale, F; Neyedley, K; Sharpe, R; Fayek, M |
| Source | TGI 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. 361-368, https://doi.org/10.4095/296476  Accès ouvert |
| Liens | Canadian Database of Geochemical Surveys, downloadable files
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| Liens | Banque de données de levés géochimiques du Canada,
fichiers téléchargeables
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| Image |  |
| Année | 2015 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/296476 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans TGI 4 -
Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation |
| Référence reliée | Cette publication est reliée à Fluid inclusion
and stable isotope evidence for mixing of magmatic- hydrothermal fluids with meteoric water in vein-type Cu-Au-Bi deposits, southern New Brunswick, Canada |
| Formats | pdf |
| Province | Nouveau-Brunswick |
| SNRC | 21A; 21G; 21H |
| Région | Mount Pleasant; Sisson |
| Lat/Long OENS | -68.0000 -66.5000 46.0000 45.0000 |
| Sujets | gisements porphyriques; cuivre porphyrique; prospection minière; minéralisation; tungstène; molybdène; étain; bismuth; cuivre; or; inclusions fluides; gîtes magmatiques; altération hydrothermale; études
des isotopes stables; filons de quartz; salinité; gisements filoniens; eaux atmosphériques; Dépôt de Mount Pleasant ; Groupe de Broad River ; géologie économique; géochimie; minéraux métalliques; Paléozoïque; Dévonien |
| Illustrations | cartes de localisation; graphiques; photographies; photomicrographies |
| Programme | Initiative géoscientifique ciblée (IGC-4) Étude des gîtes porphyriques |
| Diffusé | 2015 06 11; 2023 03 17 |
| Résumé | (disponible en anglais seulement)
Vein-type Cu-Au-Ag-Bi mineralization in the Caledonian Highlands, southern NB, Canada, is hosted within quartz-carbonate-rich shear zones cutting felsic lithic
tuffs, intermediate intrusives and interbedded felsic and mafic flows of the Neoproterozoic Broad River Group. Mineralization in the veins consists of bornitechalcocite- hematite, coprecipitated with electrum and bismuthinite; ore minerals post-date
quartz and REE-rich carbonates in the veins, with later supergene oxidation and hydration of the ores to cuprite-malachite. Wall-rock alteration is characterized by albitization and paragonitization. Replacement of bornite by chalcocite- hematite
indicates changes in fluid redox with mineralization progression.
Trails of secondary fluid inclusions in the quartz veins are two-phase liquid-vapour at room temperature. Homogenization occurs by vapour bubble disappearance between 150-270°C for
all assemblages; individual assemblages show relatively narrow ranges (e.g., 173-191°C, n=22). Bulk salinities from final ice melting range from 4 to 13 wt% NaCl eq. with individual assemblages showing similarly narrow ranges.
Stable isotope data
(bulk separates, and in-situ by secondary ion mass spectrometry [SIMS]) for vein-stage quartz (d18Obulk = 13.7-15.1perthousand; d18OSIMS-qtz = 10.8±1.5 perthousand, 1c, n=32) and carbonate (d13Cbulk = -4.4 to -4.6 perthousand) combined with
microthermometric data rule out unmodified, heated seawater and meteoric water as the dominant fluid components, and suggest that the metal-bearing fluids were magmatic in origin or represented saline formation waters modified through fluid-rock
interaction with the host volcanic rocks (calculated d18Ofluid ~ 6-7 perthousand). However, significant variations in d18OSIMS-qtz are observed within single quartz crystals across growth zones and in massive quartz texturally predating sulfides and
gold (from as low as 8.2 perthousand to 14.8 perthousand in quartz enclosed entirely within bornite-chalcocite). This indicates either (i) localized mixing of the metal-bearing fluid with low latitude meteoric water (calculated d18O = -1.0 to 0
perthousand), or (ii) fluctuations in fluid temperature during vein formation, with the lowest T portions of the vein associated with base metal-gold precipitation, or (iii) both. The isotopic composition of coeval quartz-carbonate predict a
crystallization/final equilibration T of vein-stage at ~250- 270°C; if inclusions are primary, then a maximum Ptrapping = ~1.5 kbar, based on the lowest T assemblages, is estimated.
Significant fluctuations in fO2, fluid temperature or fluid
composition during vein precipitation highlight the importance of fluid mixing for mineralization. These characteristics, combined with the style of mineralization, link these deposits in NB genetically to much larger vein Cu deposits worldwide
(e.g., Churchill, Davis-Keays, and Mamainse Point, Canada; Inyati, Zimbabwe; Copper Hills, Australia; Messina, South Africa; Cornwall, UK). |
| Sommaire | (Résumé en langage clair et simple, non publié)
L'Initiative géoscientifique ciblée (IGC-4) est un programme géoscientifique fédéral de collaboration qui fournit à l'industrie les
connaissances géoscientifiques et les techniques novatrices de prochaine génération dont elle a besoin pour mieux détecter les gîtes minéraux enfouis, réduisant ainsi certains risques liés à l'exploration. Ce volume résume les activités de recherche
effectuées dans le cadre du projet de minéralisation lié à des intrusions de l'Initiative géoscientifique ciblée 4 qui était axé sur des systèmes minéralisés porphyriques associés aux dépôts de Cu et de Cu-Mo dans le centre-sud de la
Colombie-Britannique et aux dépôts de Sn-W-Mo-In au Nouveau-Brunswick, en Nouvelle-Écosse et à Terre-Neuve-et-Labrador. |
| GEOSCAN ID | 296476 |
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