Database name: |
World Fe-oxide+/-Cu-Au-U (IOCG) deposits |
Compilers: |
Sunil S. Gandhi |
Release date: |
2015-03-04 |
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Deposit name(s): |
Merry Widow; Empire |
Political location(s): |
Canada; Province or state: British Columbia; Nearest community: Port McNeil (30 km SW) |
NTS map data: |
092L06 (Alice Lake) |
Deposit clan (type): |
Iron Skarn-type |
Deposit (sub) types: |
stacked lenses hosted mainly by andesite near limestone; located just above the intrusive contact of Coast Copper or Benson Lake stock, which dips 55° to the east; ore lenses parallel to the contact; Reference: Sangster, D. F., 1969: The Contact Metasomatic Magnetite deposits of Southwestern British Columbia; Bulletin, Geological Survey of Canada, Geological Survey of Canada, Department of Energy, Mines and Resources, Ottawa, Canada, Publication code 172, 85 p., 9 maps. |
Deposit status: |
past producer; Size category: 3 Mt |
Geologic province: |
Cordilleran Orogen |
Geologic subprovince: |
Insular Belt |
Geologic district: |
Wrangell Terrane |
Deposit object located: |
open pit |
Commodities: |
Fe |
Mineralization styles: |
stacked lenses; marginal disseminations |
Geological ages: |
Late Triassic - Early Jurassic (country rocks) Early Jurassic - Middle Jurassic (mineralization) |
Tectonic setting: |
continental marginal arc-fold belt; transpressive; Formal name: Bonanza magmatic arc (mineralization) |
Coincident features: |
intrusive contact (ore lenses parallel to the intrusive contact and discordant to the host strata); Coincident feature name: Coast Copper stock northeast-trending faults (faults dip steeply to the south; displacement of a few metres; Merry Widow and Kingfisher deposits on the Kingfisher fault); Coincident feature name: northeast faults |
Regional tectonic structure: |
broad open syncline, plunging southwest toward a monzogabbro intrusive (near deposit the strata and the intrusive contact trend north; the former dip west and the latter dips east) Tectonic structure name: Coast Copper stock margin |
Host rocks: |
(1) sedimentary; carbonate (Late Triassic, well-bedded, gently dipping to west); Magma series/sedimentary package/metamorphic group: carbonate; Depositional setting: shallow marine; Metamorphic grade: lower amphiboliteExternal host rock forms: | well bedded | Host rock protoliths: | limestone (gently folded; recrystallized near Coast Copper stock with destruction of bedding features); Host rock protolith name: Quatsino Formation of Vancouver Group | Internal host rock structures: | fine grained | Individual lithologies: | limestone (white to grey, high in calcium grading 52 to 54 % CaO and less than 2.5 % MgO) | Host rock stratigraphy: | Quatsino Formation of Vancouver Group |
(2) intrusive; gabbro-diorite suite (subvolcanic dykes and small bodies); Magma series/sedimentary package/metamorphic group: calc-alkaline; Depositional setting: hypabyssal; Metamorphic grade: lower amphiboliteExternal host rock forms: | massive | Host rock protoliths: | andesite-basalt (dykes, sills and irregular small intrusives; equivalents of Bonanza Group volcanics overlying Quatsino Formation); Host rock protolith name: Greenstone | Internal host rock structures: | fine grained to porphyritic | Individual lithologies: | basalt-andesite (variable in composition; hornfelsed and skarnified; pre-ore) | Host rock stratigraphy: | Bonanza Group equivalents |
(3) volcanic; unclassified volcanic rocks; Metamorphic grade: greenschist |
Related igneous rocks: |
(1) intrusive; quartz monzonite-monzogabbro suite (Early to Middle Jurassic Island Plutonic Suite); Initials: Coast Copper or Benson Lake stock ; Magma series: calc-alkaline; Depositional setting: hypabyssalIndividual lithologies: | gabbro-diorite-quartz monzonite (eastern part of the stock near iron deposits is gabbroic, the western part is quartz monzonitic) |
(2) intrusive; granite/tonalite-gabbro suite (post-ore dykes of diabase, alaskite and granodiorite); Initials: Post-ore dykes; Magma series: calc-alkaline; Depositional setting: hypabyssalIndividual lithologies: | diabasic and granitic (age of various dykes not certain) |
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Metallogenic signatures: |
Fe-Cu-Au-Ag-Co-Zn |
Alteration signatures: |
skarn: dioside, garnet, phlogopite; What was altered: limestone and volcanic rocks |
Mineralogy: |
(alteration): cuprite, erythrite (gangue): calcite (mineralization): magnetite, arsenopyrite, pyrite, marcasite, pyrrhotite, chalcopyrite, cobaltite, sphalerite |
Radiometric ages: |
Object dated: Alteration Signature(1); Age - Ma: 179.5; +8; -8; Dating method: K-Ar; Concentrate: phlogopite; Source rock: skarn; Formal name: skarnification; Event dated: contact metasomatism; Interpretive comment: skarn related to Coast Copper stock; 2 runs: 181 and 178 Ma; oldest age for the Island intrusions; Reference: Carson, D. J. T., 1973: The Plutonic Rocks of Vancouver Island, British Columbia: Their Petrography, Chemistry, Age and Emplacement; Paper, Geological Survey of Canada, Geological Survey of Canada, Department of Energy, Mines and Resources, Ottawa, Canada, Publication code 72-44, 70 p. |
Deposit shape: |
stacked lensesDeposit dimensions: | long axis: 225 metres width: 100 metres depth: 200 metres |
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Qualified comments: |
(Applies to: discovery and development) Magnetite in the area known since late 1890s; explored in 1950s; combined production from Merry Widow and nearby Kingfisher and Raven mines during 1957-1967 totalled 3,371,015 t ore averaging 58 % Fe |
Links to other databases: |
BC MINFILE; Key value: 092L 044 |
References: |
British Columbia Mines and Energy, 2001 |
British Columbia MINFILE Database |
Government of British Columbia, MINFILE Mineral Inventory, Internet |
Carson, D. J. T., 1973 |
The Plutonic Rocks of Vancouver Island, British Columbia: Their Petrography, Chemistry, Age and Emplacement |
Paper, Geological Survey of Canada, Geological Survey of Canada, Department of Energy, Mines and Resources, Ottawa, Canada, Publication code 72-44, 70 p. |
Eastwood, G. E. P., 1965 |
Replacement Magnetite on Vancouver Island, British Columbia |
Economic Geology, Volume 60, p. 124 - 148 |
Ettlinger, A. D.; Ray, G. E., 1990 |
Precious Metal Enriched Skarns in British Columbia: An Overview and Geological Study |
Paper, Geological Survey Branch, Mineral Resources Division, British Columbia Ministry of Energy, Mines and Petroleum Resources, Province of British Columbia, Canada, Publication code 1989-3, 128 p., 1 maps. |
Gross, G. A., 1996 |
Skarn Iron |
20. Skarn Deposits, Section 20.4 Skarn Iron, in Geology of Canadian Mineral Deposit Types, Edited by Eckstrand, O. R.; Sinclair, W. D.; Thorpe, R. I., Geology of Canada, Decade of North American Geology (DNAG), Geological Survey of Canada, Geological Society of America, Volume 8, 640 p, p. 489 - 495 |
Hudson, R., 1997 |
A Field Guide to Gold, Gemstones and Mineral Sites of British Columbia, Volume I, Vancouver Island |
Orca Book Publishers, PO Box 5626, Station B, Victoria, British Columbia, Canada, 214 p. |
Meinert, L. D., 1984 |
Mineralogy and Petrology of Iron Skarns in Western British Columbia, Canada |
Economic Geology, Volume 79, p. 869 - 882 |
Meinert, L. D., 1992 |
Skarns and Skarn Deposits |
Geoscience Canada, Volume 19, p. 145 - 162 |
Muller, J. E., 1977 |
Geology of Vancouver Island |
Open File Report, Geological Survey of Canada, Geological Survey of Canada, Publication code 463, 1 maps. |
Sangster, D. F., 1969 |
The Contact Metasomatic Magnetite deposits of Southwestern British Columbia |
Bulletin, Geological Survey of Canada, Geological Survey of Canada, Department of Energy, Mines and Resources, Ottawa, Canada, Publication code 172, 85 p., 9 maps. |
Southerland-Brown, A., 1966 |
Tectonic History of the Insular Belt of British Columbia |
in A Symposium on the Tectonic History and Mineral Deposits of the Western Cordillera in British Columbia and Neighbouring Parts of the United States, Edited by Anonymous, Special Volume, Geological Society, Canadian Institute of Mining and Metallurgy, Canadian Institute of Mining and Metallurgy, 8, 353 p, p. 83 - 100 |
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