USGS Professional Paper 1697 - Alaska Resources Library

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132 Metallogenesis and Tectonics of the Russian Far East, <strong>Alaska</strong>, and the Canadian Cordillera Slide Mountain terranes. The metamorphism and alteration are herein interpreted as occurring during either Jurassic thrusting of these terranes onto the North American Craton Margin, or more likely, during younger hydrothermal activity associated with extensive Late Cretaceous granitic magmatism. Cassiar Metallogenic Belt of Serpentinite-Hosted Asbestos Deposits, Northern British Columbia (Belt CS) The Cassiar metallogenic belt of serpentinite-hosted asbestos (and local jade) deposits occurs in northern British Columbia in the east-central part of the Canadian Cordillera (fig. 49; tables 2, 3) (Nokleberg and others, 1997b, 1998). The metallogenic belt is hosted in the altered ultramafic rocks of the Slide Mountain subduction-zone terrane. The two significant deposits are at Cassiar and adjacent McDame. Cassiar (McDame) Serpentine-Hosted Asbestos Deposit The Cassiar (McDame) serpentine-hosted asbestos deposit (fig. 59) (Burgoyne, 1986; Leaming, 1978; Northern Miner, December 12, 1987) consists of a chrysotile asbestos stockwork hosted in serpentinized alpine ultramafic intrusive rocks that occur along the fault contact of the Slide Mountain terrane and structurally underlying shelf sedimentary rocks of the passive-continental-margin Cassiar terrane (Nokleberg and 2,000 m 1,750 1,500 Footwall Thrust Sheet Sylvester Basal Thrust Fault 0 200 m South Peak McDame Asbestos Deposit others, 1997b, 1998). The deposit consists of two-fibre vein type chrysotile with magnetite that occurs in vein partings and in wall rocks, accompanied by some pyrite and jade. About 2.05 million tonnes of fibre were produced between 1953 and 1984 from 23.3 million tonnes of ore mined between 1953 to 1984. The deposit age is uncertain, but probably Cretaceous. The deposit is large and contains preproduction reserves of 55 million tonnes with high quality chrysotile. Origin of and Tectonic Controls for Cassiar Metallogenic Belt The chrysotile asbestos deposits of the Cassiar metallogenic belt occur in sheared and altered serpentine lenses and bodies that occur along the contacts between alpine ultramafic intrusions of the Slide Mountain terrane and the structurally underlying sedimentary rocks of the Cassiar passive continentalmargin terrane (Nokleberg and others, 1997b, 1998). Chrysotile veinlets, along with lizardite, antigorite, magnetite, pyrite and nephrite, formed as infiltrational replacements of serpentinite in and along shear zones (O’Hanley and Wicks, 1995). An incremental 40Ar-39Ar isotopic age of 94 Ma on phlogopite in the orebody footwall (Nelson and Bradford, 1993) is interpreted as a minimum age of serpentinization. Phlogopite formation apparently postdates metamorphism related to emplacement of the Sylvester allochthon of the Slide Mountain terrane in the Middle to Late Jurassic (Harms, 1986; Monger and others, 1991). The Slide Mountain terrane consists mainly of a faultbounded oceanic assemblage of Devonian to Permian and Limestone Thrust Sheet McDame Serpentinite Thrust Sheet Cliffs Thrust Sheet Slide Mountain Terrane Sylvester Group Serpentinite Limestone Argillite, chert, greywacke Diorite, gabbro Volcanic (greenstone) Graphitic argillite North American Continental Margin Sandpile Group Dolomite, limestone Kechika Group Argillite Fault Contact Figure 59. Cassiar (McDame) serpentine-hosted asbestos deposit, Cassiar metallogenic belt, northern British Columbia. Schematic cross section. Line of section from left to right towards 090°. Adapted from Burgoyne (1986). See figure 49 and table 4 for location.
locally Late Triassic marine volcanic and sedimentary rocks, and local mafic and ultramafic plutonic rocks (Nokleberg and others, 1994c). The terrane occurs for about 2,000 km along the length of the Canadian Cordillera (Nokleberg and others, 1997b, 1998). The Slide Mountain terrane is interpreted as a sequence of oceanic crustal rocks that formed adjacent to and were subducted under a late Paleozoic and early Mesozoic island arc now preserved as two fragments in the Quesnellia and Stikinia terranes (Nokleberg and others, 1994c; Monger and Nokleberg, 1996; Nokleberg and others, 2000). The Slide Mountain terrane occurs in large blocks to small, discontinuous remnants that are thrust over and (or) tectonically imbricated onto the Yukon- Tanana, Kootenay, and Cassiar continental-margin terranes and onto the North American Craton Margin (Nokleberg and others, 1997b, 1998). The Slide Mountain terrane is interpreted as being emplaced onto the North American Craton and Craton Margin, along with the Stikinia, Quesnellia, and Cache Creek terranes during a major period of Jurassic accretion (Monger and Nokleberg, 1996). The serpentinite-hosted asbestos deposits in the Cassiar metallogenic belt are the products of low-grade metamorphism and alteration of ultramafic rock in the Slide Mountain terranes. The metamorphism and alteration are herein interpreted as occurring during either Jurassic thrusting of these terranes onto the North American Craton Margin, or more likely, during younger hydrothermal activity associated with extensive Late Cretaceous granitic magmatism. Francois Lake Metallogenic Belt of Porphyry Mo Deposits (Belt FL), Central British Columbia The Francois Lake metallogenic belt (fig. 49; tables 3, 4) (Nokleberg and others, 1997b, 1998) is defined by the distribution of porphyry Mo deposits in felsic plutons of the Francois Lake Suite (Carter, 1982) that intrude the Stikinia, Quesnellia, and Cache Creek terranes along the eastern part of the Skeena Arch in central British Columbia. The Middle and Late Jurassic plutons of the Stag Lake (171-163 Ma) and Francois Lake (157-145 Ma) Suites (White and others, 1970; Whalen and others, 1998), with no identified coeval volcanic rocks, may correlate with the Nelson Plutonic Suite (170-155 Ma) in the southeastern part of the Canadian Cordillera. Both suites of intrusive rocks are herein interpreted as emplaced during major accretion and collision of the Stikinia-Quesnellia island arc and associated subduction-zone complexes to the west with the North American Craton Margin. Endako Porphyry Mo Deposit The Endako quartz monzonite pluton of the Francois Lake Suite hosts the Endako porphyry Mo deposit, the largest Mo deposit in Canada with initial reserves of 280 million tonnes grading 0.08 percent Mo. The deposit is essentially a stockwork of quartz-molybdenite, pyrite, and magnetite veins about 350 m wide, which extends for about 3.3 km along a west-northwesterly axis. The Endako pluton is flanked to the north and south by the younger Casey Alaskite and Francois Granite plutons, respectively. Potassic and phyllic assemblages envelope quartz- Late Jurassic Metallogenic Belts (163 to 144 Ma; figs. 48, 49) 133 molybdenite and other vein assemblages, and the host rocks are pervasively kaolinized (Dawson and Kimura, 1972; Dawson and others, 1991; Bysouth and Wong, 1995). Similar, but smaller, Mo deposits occur at Nithi Mountain, Owl Lake and to the north and northwest of Endako deposit (Dawson, 1972). Cariboo Metallogenic Belt of Au Quartz Vein Deposits (Belt CB), Southern British Columbia The Cariboo metallogenic belt of Au quartz vein deposits (fig. 49; tables 3, 4) occurs in eastern-central British Columbia and is hosted by the Early Cambrian Downey Creek Formation of the Barkerville subterrane of Kootenay terrane. The belt consists of metamorphism-related, Au-quartz-sulfide lenses that are emplaced concordantly with limestone of the Baker Member of the Downey Creek Formation and cut by discordant quartzsulfide-gold veins that occur mainly in the Rainbow Member of the Downey Creek Formation (Robert and Taylor, 1989). The significant deposits in the belt are in the Cariboo-Barkerville district and at Frasergold (table 4) (Nokleberg and others 1997a,b, 1998). The Cariboo-Barkerville district also contains major placer gold deposits (Nokleberg and others, 1997a). Cariboo-Barkerville District (Cariboo Gold Quartz, Mosquito Creek, Island Mountain) of Au Quartz Vein Deposits The Cariboo-Barkerville district contains three principal mines (Cariboo Gold Quartz, Mosquito Creek, and Island Mountain Mines) that consists of quartz-sulfide veins and pyritic replacement lenses (Robert and Taylor, 1989; Schroeter and Lane, 1991; MINFILE, 2002). The quartz-sulfide veins occur in phyllite and quartzite of the Rainbow Member, usually within 100 m of the contact with mafic volcanic rocks and limestone of the Baker Member of the Downey Creek Formation. Pyrite-gold lenses, which occur discontinuously in marble bands within the Baker Member, pre-date brittle deformation, are cut by quartz-sulfide-Au veins, and are interpreted as synmetamorphic (Robert and Taylor, 1989; Dawson and others, 1991). From 1933 to 1987, the three principal mines produced 38 tonnes of Au from 2.7 million tonnes of ore grading 13.94 g/t Au and 1.87 g/t Ag. Recent exploration of the Mountain and Bonanza Ledge deposits indicates a probable reserve of 3,109,800 tonnes grading 2.95 g/t Au (International Wayside Gold Mines 2003 Annual Report). The associated Wells-Barkerville placer Au district also produced 64.8 tonnes of Au between 1850 and 1990. The deposit age is interpreted as Middle Jurassic through Early Cretaceous. Frasergold Au-Quartz Vein Deposit The Frasergold Au quartz vein deposit consists of pyrrhotite, pyrite and coarse-grained gold and minor galena, sphalerite, and chalcopyrite that occur in deformed quartz-carbonate veins and stockwork stratabound in at least three stratigraphic horizons in porphyroblastic phyllite (Eureka <strong>Resources</strong> Inc.,
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USGS Prepared in collaboration with
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U.S. Department of the Interior Gal
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iv Hart River SEDEX Zn-Cu-Ag Deposi
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vi Specific Events for Middle Throu
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viii Metallogenic Belts Formed Duri
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x Origin of and Tectonic Controls f
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xii Toodoggone Metallogenic Belt of
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xiv Slate Creek Serpentinite-Hosted
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xvi Left Omolon Belt of Porphyry Mo
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xviii Origin of and Tectonic Contro
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xx Chukotka Metallogenic Belt of Au
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xxii Plutonic Rocks Hosting East-Ce
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xxiv Skeena Metallogenic Belt of Po
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xxvi Bee Creek Porphyry Cu Deposit
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xxviii 36. Wellgreen gabbroic Ni-Cu
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xxx 87. Partizanskoe Pb-Zn skarn de
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Metallogenesis and Tectonics of the
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format (Nokleberg and others, 1996)
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logenesis of the region (1) subduct
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Subterrane—A fault-bounded unit w
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dilemma consists of two conflicting
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2 to 20 m thick. A related dolomite
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Lantarsky-Dzhugdzhur Metallogenic B
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Origin of and Tectonic Controls for
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Metallogenic Belts Formed During Pr
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as at Oz, Monster, and Tart, may al
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Monashee Metallogenic Belt of Sedim
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Clark Range Metallogenic Belt of Se
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in addition to the Fe deposits. Min
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study) consists of lenses, from 100
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Omulev Austrian Alps W Deposit The
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ock, including coarse clastic rock,
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lative metalliferous brines in a re
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Prince of Wales Island Metallogenic
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suite of deposits and host rocks ar
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margin of the North American Craton
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newly created terranes migrated int
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(Ryazantzeva and Shurko, 1992). The
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tonnes Au and an average grade of a
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mafic and felsic metavolcanic rocks
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intrusion from about 402 to 366 Ma
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mentary rocks of the Cambrian to De
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(Preto and Schiarizza, 1985; Schiar
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ate and clastic rocks and volcanicl
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(Nokleberg and others, 1994c, 1997c
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Berezovka River Metallogenic Belt o
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Finlayson Lake Metallogenic Belt of
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and barite in siliceous black turbi
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Windermere Creek (Western Gypsum) C
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(NX, DL, MY), Viliga (VL), and Zolo
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South of the main east-west-trendin
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ated subduction zone in the Wrangel
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icite-biotite-quartz bodies in frac
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Page 115 and 116: Viliga (VL) passive continental-mar
Page 117 and 118: 32; tables 3, 4) occurs along the n
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Page 125 and 126: a resource of 34.3 million tonnes o
Page 127 and 128: potassic zone. Combined estimated p
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Page 131 and 132: and Omolon (OM) cratonal terranes,
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Page 139 and 140: deposits and occurrences consist of
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Page 143 and 144: superterrane. This belt is interpre
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Page 149 and 150: deposits are at Terrassnoe and Kuna
Page 151 and 152: Peschanka Porphyry Cu-Mo Deposit Th
Page 153 and 154: The belt is hosted in the Late Jura
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Page 159 and 160: The deposit consists of disseminate
Page 161 and 162: The Orange Hill deposit contains an
Page 163: 49; tables 3, 4) (Foley and others,
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Page 169 and 170: Verkhoyansk granite belt, which int
Page 171 and 172: metallogenic belts are interpreted
Page 173 and 174: assemblages, which may have been mo
Page 175 and 176: during hypogene and supergene alter
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Page 179 and 180: Yur Au Quartz Vein Deposit The smal
Page 181 and 182: phase has a Rb-Sr isotopic age of 1
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Page 185 and 186: Host Granitoid Rocks and Associated
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Page 189 and 190: Metallogenic Belts Formed During La
Page 191 and 192: y partly coeval plutons that range
Page 193 and 194: tion is interpreted as occuring by
Page 195 and 196: the Badzhal-Ezop and Khingan parts
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Page 199 and 200: as interpreted for the Rock Creek d
Page 201 and 202: source (Yeo, 1992). The Blow River
Page 203 and 204: 2000). The spatial location of the
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Page 207 and 208: occur in a 30-km-long belt along ir
Page 209 and 210: The Emerald deposit has produced ap
Page 211 and 212: Metallogenic-Tectonic Model for Ear
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greisenized Mesozoic granite that i
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composition magmatic bodies (with a
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to Albian pelecypods (Nokleberg and
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quartz-arsenopyrite-pyrrhotite, pol
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thermally altered to siliceous and
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These ore bodies are as much as 1 m
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Eastern Asia-Arctic Metallogenic Be
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Demin, and Krasilnikov, 1974; Nekra
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10 percent Cu, as much as 0.92 perc
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pyrite, pyrite, galena, sphalerite,
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content decreases with depth, as do
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azdelnoye, (2) porphyry Sn deposits
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Karalveem Au Quartz Vein Deposit Th
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Democrat (Mitchell Lode) Granitoid-
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with high-temperature and high-pres
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chalcocite and covellite and also h
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cum-North Pacific, (2) completion o
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(6) In the Paleocene (about 56 to 6
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sists of cinnabar and metacinnabari
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Eastern Asia-Arctic Metallogenic Be
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groups of deposits are interpreted
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Indian Mountain and Purcell Mountai
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and southeastern Alaska (Moll and P
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Nokleberg and others, 1995a; Bundtz
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g/t Au or 368.2 Au gold. The deposi
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wim Group and altered mafic dikes.
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Mount Nansen porphyry Cu-Mo deposit
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A Map 450 500 550 Cross section Dik
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Cretaceous and early Tertiary conti
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deposits, at Chichagoff and Hirst-C
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others, 1994c, 1997c). The signific
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tonnes grading 0.53 percent Ni, 0.3
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with a 0.25 percent cut-off. The de
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Bulkley Metallogenic Belt of Porphy
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Red Rose W-Au-Cu-Ag Polymetallic Ve
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ish Columbia and consists of severa
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during back-arc extension or transt
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stocks and dikes, is associated wit
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etrograde minnesotaite (Fe talc), F
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Specific Events for Early to Middle
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of fractured and faulted Permian-Tr
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sists of a mineralized fracture zon
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dolomite. Wall rock alteration incl
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elt of late Tertiary plutons that a
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plates that exhibit magnetic anomal
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stages (Petrenko, 1999): (1) In the
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mon. The deposit is of medium size
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Metallogenic-Tectonic Model for Lat
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The origin of the Hg deposits of th
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margin or island-arc tectonic envir
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Columbia: Implicatons for the Middl
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Bazard, D.R., Butler, R.F., Gehrels
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Bradley, D.C., Haeussler, P.J., and
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Bundtzen, T.K., Laird, G.M., Caluti
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Cecile, M.P., 1982, The lower Paleo
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Debari, S.M., and Coleman, R.G., 19
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U.S. Bureau of Land Management Open
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Cordilleran Orogen in Canada: Geolo
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Goldfarb, R., Hart, C., Miller, M.,
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Grove, E.W., 1986, Geology and mine
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Høy, T., 1982a, Stratigraphic and
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Jones, D.L., Silberling, N.J., Cone
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Kutyev, F. Sh., Baikov, A.I., Sidor
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Shield—Ultramafic magma and its m
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Manns, F.T., 1981, Stratigraphic as
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Miller, M.L., and Bundtzen, T.K., 1
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Mortimer, N., 1987, The Nicola Grou
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Noble, S.R., Spooner, E.T.C., and H
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Canada Annual Meeting, Saskatoon, S
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Perello, J.A., Fleming, J.A., O’K
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Far East—Mineralogical criteria f
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Roeske, S.M., Mattinson, J.M., and
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Schmidt, J.M., and Zierenberg, R.A.
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formation occurrences: Materialy po
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Struik, L.C., 1986, Imbricated terr
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Valuy, G., and Rostovsky, F., 1988,
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Wolfe, W.J., 1995, Exploration and
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Appendix Table 1. Mineral deposit m
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Table 2 Summary of correlations and
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Table 2—Continued Unit(s) and Cor
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Table 2—Continued Unit(s) and Cor
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Table 3—Continued Metallogenic Be
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Table 4. Significant lode deposits,
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Table 4—Continued Appendix 369 De
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Table 4—Continued Tracy Metalloge
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Table 4—Continued Appendix 373 In
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Table 4—Continued Deposit Name Mi
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Table 4—Continued Mainits Metallo
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Table 4—Continued Whitehorse Meta
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Table 4—Continued Appendix 389 LA
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Table 4—Continued Surprise Lake M
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Table 4—Continued Sredinny Metall
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