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TitleGeological and geochemical characteristics of the Waconichi Formation east of the Lemoine auriferous volcanogenic massive sulphide deposit, Abitibi greenstone belt, Quebec
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorBoulerice, 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; by Peter, J MORCID logo (ed.); Mercier-Langevin, P (ed.); Geological Survey of Canada, Open File 7853, 2015 p. 171-182, Open Access logo Open Access
LinksCanadian Database of Geochemical Surveys, downloadable files
LinksBanque de données de levés géochimiques du Canada, fichiers téléchargeables
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
RelatedThis publication is contained in Targeted Geoscience Initiative 4: Contributions to the understanding of volcanogenic massive sulphide deposit genesis and exploration methods development
File formatpdf
NTS32G/09; 32G/10; 32G/15; 32G/16
Lat/Long WENS -75.0000 -74.0000 50.0000 49.5000
Subjectseconomic geology; metallic minerals; structural geology; igneous and metamorphic petrology; geochemistry; Archean; volcanogenic deposits; sulphide deposits; alteration; metamorphism; mineral assemblages; mineralization; exploration guidelines; volcanic rocks; mineral deposits; gold; metallogeny; greenschist facies; deformation; chlorite; sericite; epidote; chloritoid; tectonic setting; hydrothermal alteration; hydrothermal deposits; lithology; rhyolites; dacites; andesites; basalts; gabbros; porphyries; geochemical analyses; trace element geochemistry; major element geochemistry; Abitibi greenstone belt; Lemoine deposit; Waconichi Formation; Lemoine Member; Precambrian
Illustrationslocation maps; cross-sections; plots; photographs
ProgramTargeted Geoscience Initiative (TGI-4) Volcanogenic Massive Sulfide Ore Systems
Released2015 06 11; 2023 03 17
AbstractThe 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.
Summary(Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. This volume summarizes 12 research activities completed under the TGI-4 volcanogenic massive sulphide ore systems project that focused on the understanding of the genesis of precious metal enriched VMS deposits as well as on VMS vectoring and unconventional detection methods development.

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