| Titre | Petrologic and geochemical examination of the Early Devonian, Evandale porphyry Cu-Mo-(Au) deposit, southern New Brunswick: geothermobarometric analysis of petrogenesis |
| Télécharger | Téléchargement (publication entière) |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | White, T; Lentz, D R; McFarlane, C R 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. 343-360, https://doi.org/10.4095/296475  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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| Année | 2015 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/296475 |
| 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 Petrologic and
geochemical examination of the Early Devonian, Evandale porphyry Cu-Mo-(Au) deposit, southern New Brunswick: geothermobarometric analysis of petrogenesis |
| 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; dépôts glaciaires; minéralisation; tungstène; molybdène; étain; bismuth; cuivre; or; caractéristiques structurales; roches intrusives;
granodiorites; analyses pétrographiques; pétrogenèse; géobarométrie; géothermométrie; analyses géochimiques; Dépôt de Mount Pleasant ; géologie économique; géochimie; pétrologie ignée et métamorphique; Paléozoïque; Dévonien |
| Illustrations | cartes de localisation; coupes transversales; blocs-diagrammes; photographies; photomicrographies; diagrammes Concordia; diagrammes ternaires; graphiques |
| Programme | Initiative géoscientifique ciblée (IGC-4) Étude des gîtes porphyriques |
| Diffusé | 2015 06 11 |
| Résumé | (disponible en anglais seulement)
Porphyry Cu-Mo-(Au) systems associated with the granitoid rocks in eastern North American orogenic belts have been researched using current deposit models;
however, relatively few studies have examined the potential for late stage fine-grained porphyritic to aplitic intrusive phases being host to mineralization. The Evandale Granodiorite is an example of a well- preserved Mid-Devonian (U-Pb zircon age
of 391.2 ± 3.2 Ma for the coarser granitoid, and 390.2 ± 1.6 Ma for the aplite) polyphase pluton intruding through deformed Silurian sedimentary and mafic volcanic rocks of the Mascarene Basin in southern New Brunswick. The two intrusive phases have
been identified as I type granites with a minor sedimentary component. The pluton is separated both petrochemically and texturally into two distinct phases. The coarser phase ranges from medium- to coarse-grained seriate to porphyritic granodiorite
to monzogranite and the later finer stage layered aplite ranges from a monzogranite to syeno-granite. INAA analysis of each phase found that the highest concentrations of Cu and Au (108 ppm Cu, and 33 ppb Au) are associated with pyrite, chalcopyrite,
and arsenopyrite within the aplitic dykes sampled, whereas concentrations of up to 6 ppm Mo were detected within the c.g. granite. Current models suggest that the transport of metals (particularly Cu and Au) are sourced from secondary two-phase
fluids at shallow depths (approximately 2 kb), and is controlled primarily by Cl fugacity of the magma. Analyses of biotite phenocrysts from both the aplite and granite contain an average of 0.21 wt% Cl, which is similar to other high grade
Cu-Mo-(Au) porphyry deposits. Average zircon saturation temperatures were calculated to be 818°C for the aplite and 787°C for the granitoid. Average apatite saturation temperatures were found to be 880°C for the aplite and 934°C for the granitoid
phase. Hornblendeplagioclase thermometry revealed the crystallization temperature of the granite to be 642°C and 600°C for the aplite, cooler than most deposits of the same type. Al in hornblende geobarometery indicates crystallization depths of ~2.1
kb for hornblende in the aplite and ~0.7 kb for the c.g. granite. The aplitic dykes were subject to higher crystallization pressures and lower crystallization temperatures suggesting that their formation may either be a result of pressure quenching
of the melt during rapid ascent or by the sub-solidus recrystallization of the melt as pyroclastic flows. |
| 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 | 296475 |
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