| Titre | Evolution of the subseafloor hydrothermal system associated with the Ming VMS deposit, Newfoundland Appalachians, and its controls on base and precious metal distribution |
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| Auteur | Pilote, J -L; Piercey, S J; Mercier-Langevin, P |
| Source | Mineralium Deposita vol. 54, 2019 p. 1-24, https://doi.org/10.1007/s00126-019-00899-z |
| Image |  |
| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190156 |
| Éditeur | Springer Science and Business Media LLC |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1007/s00126-019-00899-z |
| Media | en ligne; numérique |
| Formats | pdf (Adobe® Reader®); html |
| Province | Terre-Neuve-et-Labrador |
| SNRC | 12H/16 |
| Région | Baie Verte Peninsula |
| Lat/Long OENS | -56.1397 -56.0217 49.9317 49.8658 |
| Sujets | prospection minière; gisements minéraux; gîtes volcanogènes; gîtes sulfureux; métaux de base; métaux précieux; cuivre; argent; or; nickel; zinc; fer; minéralisation; genèse des minerais; contrôles
structuraux; cadre tectonique; évolution tectonique; système hydrothermal; volcanisme; altération; altération hydrothermale; paragenèse; précipitation; analyses thermiques; fluage; réseaux de pH; enrichissement des minéraux; métamorphisme;
déformation; intrusions; filons rocheux; filons-couches; mise en place; roches hôtes; géologie du substratum rocheux; lithologie; roches ignées; roches volcaniques; rhyodacites; volcanoclastique; roches intrusives; roches intrusives mafiques; roches
sédimentaires; schistes; siltstones; caractéristiques structurales; failles; assemblages de minéraux; eprentes; lithofaciès; lithogéochimie; analyses spectrométriques; analyses des éléments majeurs; établissement de modèles; filons; Ceinture
Orogénique Appalachienne; Zone de Dunnage ; Sous-Zone de Notre Dame ; Ligne de Baie Verte-Brompton ; Groupe de Snooks Arm ; Formation de Venam's Bight ; Formation de Bobby Cove ; Formation de Scrape Point ; Dépôt de Rambler ; géologie économique;
géochimie; minéralogie; tectonique; stratigraphie; Sciences et technologie; Phanérozoïque; Paléozoïque; Silurien; Ordovicien; Cambrien; Précambrien; Protérozoïque |
| Illustrations | cartes de localisation; cartes géolscientiques généralisées; échelles stratigraphiques; tableaux; coupes schématiques transversales; photographies; photomicrographies; graphiques; graphique à
barres; profils; représentations schématiques |
| Programme | Initiative géoscientifique ciblée (IGC-5) Systèmes minéralisés aurifères - Commandes du système - Temps et espace |
| Diffusé | 2019 07 08 |
| Résumé | (disponible en anglais seulement)
The ~487 Ma Ming volcanogenic massive sulfide (VMS) deposit consists of four subparallel, elongated, semi-massive to massive sulfides lenses (the 1807, 1806,
Ming North, and Ming South zones) hosted in rhyodacite of the Rambler Rhyolite formation, Newfoundland Appalachians. A discordant Cu-rich Lower Footwall zone underlies the semi-massive to massive sulfide lenses. Alteration associated with
mineralization can be divided into nine facies that formed in three paragenetic stages: (1) weak quartz-calcite ± spessartine, quartz-sericite, and quartz-sericite-chlorite alteration (stage 1); (2) quartz-chlorite, quartz-chlorite-sulfide, and
quartz-chlorite-sericite assemblages (stage 2); and (3) quartz-sericite-sulfide and localized Mn-rich carbonate assemblages (stage 3). A thin syngenetic silica-rich layer immediately overlies part of the VMS deposit and likely formed during the early
stages. The volcanic architecture and synvolcanic faults controlled the lateral distribution of extrusive rocks and hydrothermal alteration. Precipitation of the high temperature, discordant to semi-conformable Cu-rich chloritic assemblages
(stockwork), was laterally restricted to one of these synvolcanic faults and the transition from coherent- to volcaniclastic-dominated lithofacies. Lower temperature, sericitic assemblages (stages 1 and 3) are controlled by the distribution of
volcaniclastic rocks and generally form the immediate footwall to the semi-massive to massive sulfide lenses. Lithogeochemical mass balance calculations illustrate the alteration minerals and mineralization: chlorite-rich assemblages - gains in SiO2,
Fe2O3t, MgO, Cr, Ni, and Cu and losses in Na2O, MnO, and CaO and sericite-rich assemblages - gains in K2O, Zn, and Ag and losses in MnO, MgO, CaO, Na2O, and Y. Calcium- and magnesium-rich alteration assemblages are restricted to the northwest fringe
of the deposit, distal to the main chloritic and sericitic alteration, and have elemental gains in P2O5, Y, and losses in K2O. The late stage 3 quartz-sericite-sulfide assemblage overprints most assemblages, hosts
sphalerite-galena-sulfosalt-Ag-Au-rich veins, and is spatially associated with coherent volcanic rocks. The less permeable nature of these rocks is interpreted to have acted as a physical barrier for ascending metal-rich hydrothermal fluids. Results
from the detailed reconstruction of the hydrothermal architecture and paragenetic evolution of the Ming deposit suggest that precious metals were introduced during the waning stage of the hydrothermal system, associated with decreases in temperature
and pH of the hydrothermal fluids. |
| GEOSCAN ID | 315047 |
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