Gold-bearing veins around a felsic stock near Wawa, Ontario: implications for gold exploration

Abstract A trondhjemite stock intrudes a volcanic sequence that has massive sulphide lenses and that is metamorphosed to the green-schist fades at Gutcher Lake, 25 km north of Wawa, Ontario. The stock is 4 km2 in plan and is partly enveloped by an aureole of chlorite-epidote-amphibole hornfels up to 1 km wide. Within this contact aureole, biotite is partly pseudomorphosed by chlorite; epidote and hornblende are mottled by chlorite, calcite, plus quartz; albite has 0% An to 8% An; and hornblende porphyroblasts have actinolite rims. The stock has chlorite pseudomorphous after biotite; and feldspar is mottled by white mica plus calcite and has a clear rim of albite. Fractures filled with quartz, calcite, ankerite, chlorite, white mica, pyrite, and native gold cross-cut the stock and its hornfels aureole. These gold-bearing veins are enveloped by foliated rocks with quartz, calcite, white mica, and chlorite that grade outward from the veins into trondhjemite or hornfels.
The stock, emplaced into a submarine volcanic series, emanated heat that caused seawater to convect and formed a contact aureole of hornblende hornfels. The stock eventually intruded its aureole and this culminated with regional meta-morphism to the greenschist fades. Regional metamorphism hydrated the stock and its hornfels aureole. Native gold precipitated with quartz along fractures from metamorphic fluids in response to cooling and wallrock hydration. Exploration for this type of gold deposits should focus around felsic intrusions that have albite and that have contact aureoles retrograded by regional metamorphism.
Keywords: Gold exploration, Gold-bearing veins, Regional metamorphism, Retrograde metamorphism, Felsic intrusions, Greenstone belts, Mineral alteration.
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Summary: The Cape Ray Fault Zone of southwestern Newfoundland contains two notable electrum/base metal sulphide quartz vein lode occurrences hosted by two contrasting lithological units, viz. a graphite schist horizon and a granite. The two occurrences, although in proximity, are not in direct contact, but, based on geochronological, geochemical and isotopic evidence, they were apparently deposited from hydrothermal fluids generated as a vapour phase from the magmatic progenitor of the Windowglass...
Publication: CIM Bulletin
Author(s): DEREK H.C.WILTON
Keywords: Gold mineralization, Rare earth elements, Cape Ray, Electrum deposits, Hydrothermal fluids, Gold, Silver, Granites.
Issue: 874
Volume: 78
Year: 1985
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Summary: A low-grade concentrate from the Crevier Township, Quebec, containing 1.8% Ta2O5 and 13.7% Nb2O5 was reduced with carbon at 1600"C, and niobium and tantalum were selectively absorbed in liquid iron. To slag off the zirconia-rich gangue, some silica and lime were added as flux. Metallic iron was added in such a way that the combined contents of TaC and NbC did not exceed 20% in the ferroalloy. Up to 95% of the niobium, and up to 80% of the tantalum contained in the concentrate were...
Publication: CIM Bulletin
Author(s): M. NAGAMORI, A.J. PLUMPTON
Keywords: Pyrometallurgy, Smelting, Leaching, Calcination, Niobium, Tantalum, Ferroalloys.
Issue: 874
Volume: 78
Year: 1985
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Summary: The recent opening of Muscocho's gold mine at Montauban, as well as the discovery of several new copper-gold showings of a similar nature near the confluence of the Saguenay and St. Lawrence has revealed the existence of a new metallogenic gold province which is located within supercrustal units of Helikian age within the Grenville Province. Three metalliferous belts have been identified, each one of which is related to a series of SW-NE trending faults. The first is located in southeastern...
Publication: CIM Bulletin
Author(s): MICHEL GAUTHIER, GAETAN MORIN, PIERRE MARCOUX
Keywords: Gold mineralizalion, Gold, Melallogeny, Grenville Province, Monlauban region.
Issue: 874
Volume: 78
Year: 1985
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Summary: Kidd Creek is a large volcanogenic base metal sulphide deposit, located near the west end of the Abitibi greenstone belt, 27 km north of Timmins, Ontario. The rhyolite geology is characterized by a NNE-striking and steeply east-dipping package of rhyolite volcaniclastics upon which has been imposed a strong ESE-striking and north-dipping structural fabric. Massive rhyolite units with grey-black, chloritic cores and yellow, sericitic margins intrude as dykes into the stratigraphic footwall and...
Publication: CIM Bulletin
Author(s): P.P. GOAD
Keywords: Economic geology, Kidd Creek Mine, Volcanogenic deposits, Base metal sulphide deposits, Rhyolite geology, Massive rhyolites, Rhyolite volcaniclastic, Crackle-brecciated rhyolites, Stringer sulphide zone, Hydrothermal alteration, Mature alteration, Immature alteration, Hydraulic fracturing, Evolution felsic pile, Exploration.
Issue: 874
Volume: 78
Year: 1985
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