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TitreGeological and geochemical characteristics of the Waconichi Formation east of the Lemoine auriferous volcanogenic massive sulphide deposit, Abitibi greenstone belt, Quebec
TéléchargerTéléchargement (publication entière)
AuteurBoulerice, A R; Ross, P -S; Mercier-Langevin, P
SourceTargeted Geoscience Initiative 4: Contributions to the understanding of volcanogenic massive sulphide deposit genesis and exploration methods development; par Peter, J M (éd.); Mercier-Langevin, P (éd.); Commission géologique du Canada, Dossier public 7853, 2015 p. 171-182, https://doi.org/10.4095/296551
Année2015
ÉditeurRessources naturelles Canada
Documentdossier public
Lang.anglais
DOIhttps://doi.org/10.4095/296551
Mediaen ligne; numérique
Référence reliéeCette publication est contenue dans Peter, J M; Mercier-Langevin, P; (2015). Targeted Geoscience Initiative 4: Contributions to the understanding of volcanogenic massive sulphide deposit genesis and exploration methods development, Commission géologique du Canada, Dossier public 7853
Formatspdf
ProvinceQuébec
SNRC32G/09; 32G/10; 32G/15; 32G/16
Lat/Long OENS -75.0000 -74.0000 50.0000 49.5000
SujetsArchéen; gîtes volcanogènes; gîtes sulfureux; altération; métamorphisme; assemblages de minéraux; minéralisation; directives d'exploration; roches volcaniques; gisements minéraux; or; métallogénie; faciès à schiste vert; déformation; chlorite; séricité; épidote; chloritoïde; cadre tectonique; altération hydrothermale; gisements minéraux hydrothermaux; lithologie; rhyolites; dacites; andésites; basaltes; gabbros; porphyres; analyses géochimiques; géochimie des éléments en trace; géochimie des éléments majeurs; Ceinture d'Abitibi Greenstone ; Formation de Waconichi ; géologie économique; minéraux métalliques; géologie structurale; pétrologie ignée et métamorphique; géochimie; Précambrien
Illustrationslocation maps; cross-sections; plots; photographs
ProgrammeÉtude des gîtes de sulfures massifs volcaniques, Initiative géoscientifique ciblée (IGC-4)
LiensCanadian Database of Geochemical Surveys, downloadable files
LiensBanque de données de levés géochimiques du Canada, fichiers téléchargeables
Diffusé2015 06 11
Résumé(disponible en anglais seulement)
The Lemoine Mine exploited a small but exceptionally rich auriferous volcanogenic massive sulphide body (0.76 Mt of ore grading 4.6 g/t Au). The deposit was located in the Lower Lemoine Member of the Waconichi Formation, in the Chibougamau area of the Archean Abitibi greenstone belt. The Lower Lemoine Member, which is mostly of tholeiitic magmatic affinity, is overlain by the Upper Lemoine Member comprising transitional basalt and transitional to calc-alkaline rhyolite. Field mapping, geochemical analyses, and detailed core logging of every accessible drillhole in the study area, east of the former mine, has helped to define the Lower Lemoine Member subunits and identify their mode of emplacement. The Lower Lemoine Member is composed of multiple extrusive subunits: from the bottom of the volcanic stratigraphy, the Alpha Rhyolite followed by the Lemoine Rhyolite, the Lemoine Dacite, the Lemoine Andesite, and the Hanging-wall Quartz and Feldspar Porphyry. A second, later, component of the Alpha Rhyolite intrudes the Lemoine Rhyolite locally. The Marelle Quartz and Feldspar Porphyry and the Coco Lake Rhyolite represent subvolcanic intrusions that form concordant sills at multiple stratigraphic levels in the Lower Lemoine Member. Preliminary results also indicate the potential presence and general location of previously unrecognized volcanic vents northeast of the Lemoine deposit, which may have been the site of paleohydrothermal fluid up-flow and may host additional mineralization. The precise location of the volcanic vents is the topic of ongoing work and will have implications for exploration for volcanogenic massive sulphides in the area and in similar settings elsewhere. Moreover, our work indicates that the Lemoine auriferous volcanogenic massive sulphide deposit is hosted in a felsic-dominated volcanic sequence comprising a significant portion of shallow intrusive rocks, defining a major thermal corridor over a large synvolcanic intrusion; conditions that may have contributed in forming such a base- and precious-metal-rich deposit.
GEOSCAN ID296551