CANADIAN AND WORLD MINERAL DEPOSIT DATABASES
Geological Survey of Canada


Deposit number Country Location Names Commodities
798 Canada (British Columbia) 49.03.00 N -- 125.26.00 W Brynnor Fe
 
Database name: World Fe-oxide+/-Cu-Au-U (IOCG) deposits
Compilers: Sunil S. Gandhi
Release date: 2015-03-04
   
Deposit name(s): Brynnor
Political location(s): Canada; Province or state: British Columbia; Nearest community: Ucluelet, Vancouver Island (14.5 km NE)
NTS map data: 092F03 (Effingham River)
Deposit clan (type): Iron Skarn-type
Deposit (sub) types: massive lensoid magnetite body 500 m long; strike NNE; plunge to south; sharp boundaries with host limestone; some veins and disseminations near ore body; serpentine along post-ore faults and shears; 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.
host strata were folded prior to mineralization into two synclines separated by an anticline, and the ore body is affected by later folding, faulting and shearing, marked by serpentine-lined fractures; 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: 4.5 Mt
Geologic province: Cordilleran Orogen
Geologic subprovince: Insular Belt
Geologic district: Wrangell Terrane
Deposit object located: open pit
Commodities: Fe
Mineralization styles: massive; veins; disseminations around massive bodies
Geological ages: Late Triassic - Early Jurassic (host rocks)
Early Jurassic (mineralization)
Tectonic setting: continental marginal arc-fold belt; transpressive; Formal name: Bonanza Magmatic Arc (host rocks)
Coincident features: limestone-andesite contact (north pod near surface has replaced limestone; it plunges southwest and meets ); Coincident feature name: Quatsino Formation
folding (ore apparently localized in axial zone of a syncline); Coincident feature name: Kennedy Lake sequence
Regional tectonic structure: folded host strata trending northeast (pre-ore folds, truncated by granodiritic stock, and post-ore deformation) Tectonic structure name: Quatsino Formation
Host rocks: (1) sedimentary; carbonate (Late Triassic bedded limestone); Depositional setting: arc-back arc basin; Metamorphic grade: lower amphibolite
External host rock forms:well bedded
massive
Host rock protoliths:carbonate (bedded and massive separated by calcareous tuff member)
Internal host rock structures:fine grained
Individual lithologies:limestone and tuffaceous sediments (three members: lower bedded limestone, middle calcareous tuff 250 m thick and upper massive limestone 100 m thick)
Host rock stratigraphy:Quatsino Formation of Vancouver Group

(2) volcanic; intermediate-felsic volcanic rocks (andesite intruive into limestone); Magma series/sedimentary package/metamorphic group: calc-alkaline; Depositional setting: arc-back arc basin; Metamorphic grade: lower amphibolite
External host rock forms:flows, tuffs and agglomerate
Host rock protoliths:andesite (the andesite occurs between Quatsino limestone and Bonanza tuffs, and is likely related to the latter); Host rock protolith name: Kennedy Lake sequence
Internal host rock structures:massive to porphyritic
Individual lithologies:andesite (the volcanics of lower part of Kennedy Lake sequence is comparable with those of Karmutsen Formation)
Host rock stratigraphy:Kennedy Lake sequence of Vancouver Group

(3) volcanic; intermediate volcanic rocks (Lower Jurassic andesitic tuffs and flows ); Depositional setting: arc-back arc basin; Metamorphic grade: lower amphibolite
External host rock forms:flows, tuffs and agglomerate
Host rock protoliths:andesites (in fault contact with the Quatsino Formation; the upper member of the formation may be Lower Juarrsic in age); Host rock protolith name: Bonanza Group volcanics
Internal host rock structures:massive to porphyritic
Individual lithologies:andesite (andesitic dykes and sills and an apparently intrusive body in the Quatsino Formation are pre-ore)
Host rock stratigraphy:Bonanza Group

(4) intrusive; granodiorite-tonalite-diorite suite (Early to Middle Jurassic pluton); Magma series/sedimentary package/metamorphic group: calc-alkaline; Depositional setting: arc-back arc basin; Metamorphic grade: none
External host rock forms:massive, porphyritic to equigranular
Host rock protoliths:granodiorite-diorite (the pluton truncates the host sequence south of the deposit, and also occurs to the west and north); Host rock protolith name: Island Plutonic suite
Internal host rock structures:medium grained, equigranular
Individual lithologies:granodiorite-diorite (a marginal phase near the deposit is petrographically and chemically quartz monzonite)
Host rock stratigraphy:Island Plutonic suite
Related igneous rocks: (1) intrusive; quartz monzonite-monzogabbro suite (early Jurassic; likely source of mineralization); Initials: Island Plutonic suite; Magma series: calc-alkaline; Depositional setting: hypabyssal
Individual lithologies:granodiorite-quartz monzonite (a granodioite-quartz diorite stock with marginal phase of quartz monzonite observed near the deposit)

(2) intrusive; gabbro suite (small pre-ore dykes, serpentinized); Initials: Pre-ore dykes; Magma series: calc-alkaline; Depositional setting: hypabyssal
Individual lithologies:gabbroic (altered to serpentine-rich assemblage)

(3) intrusive; gabbro suite (small basic dykes, slightly serpentinized); Initials: Pre-ore mafic dykes; Magma series: calc-alkaline; Depositional setting: hypabyssal
Individual lithologies:diabase (a few of the dykes are rimmed with skarn zone where they cut limestone)

(4) intrusive; gabbro-diorite suite (youngest dyke in the deposit area); Initials: Diabase dyke; Magma series: calc-alkaline
Individual lithologies:diabase (only one dyke of unaltered diabase is known near the deposit)

(5) intrusive; gabbro-diorite suite (post-ore dykes, up to 10 m wide); Initials: Leucodiorite dykes; Magma series: calc-alkaline; Depositional setting: hypabyssal
Individual lithologies:leucodiorite (Tertiary syenite porphyry to dioritic dykes; variable proportion of feldspar and pyroxene; either mineral may occur as scattered phenocrysts)
Metallogenic signatures: Fe
Alteration signatures: skarn: garnet and diopside; What was altered: limestone and andesitic host rocks
serpentinization: serpentine; What was altered: iron ore and andesitic intrusives
epidotization: epidote; What was altered: mafic silicates
chloritization: chlorite; What was altered: mafic silicates
sericitization: sericite; What was altered: fledspar in andesitic rocks
carbonatization: calcite, recrystallized; What was altered: limestone
Mineralogy: (alteration): garnet, serpentine, epidote, chlorite, sericite
(gangue): calcite
(mineralization): magnetite, pyrite, pyrrhotite
Radiometric ages: Object dated: Related igneous rocks(1); Age - Ma: 167; +10; -10; Dating method: K-Ar; Concentrate: biotite; Source rock: granodiorite; Formal name: Island Intrusion; Event dated: intrusive event; Interpretive comment: the radiometric age is consistent with the middle Jurassic age deduced from the geological relations; 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: elongate plunging lens
Deposit dimensions:strike length: 500 metres
width: 20 metres
depth: 125 metres
Qualified comments: (Applies to: discovery and development) A strong magnetic anomaly reported in 1902; explored in 1960; open pit production during 1962- 1968 totalled 4,480,940 tonnes of ore from which 3,011,306 tonnes of Fe recovered; traces of Fe sulphides. 250 000 tonnes of limestone were gathered from the dumps and shipped in 1998.
Links to other databases: BC MINFILE; Key value: 092F 001
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.

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

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.


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