USGS Professional Paper 1697 - Alaska Resources Library

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92 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera Origin of and Tectonic Controls for Copper Mountain (North) Metallogenic Belt The Copper Mountain (North) metallogenic belt is hosted mainly in intermediate-composition granitoid plutons in the Copper Mountain suite, which are part of the subductionrelated Quesnellia island arc (Nokleberg and others, 1994a,b; Monger and Nokleberg, 1996; Nokleberg and others, 2000). Emplacement of plutons was apparently along faults and intersections of faults. In both the Copper Mountain (North) and Copper Mountain (South) metallogenic belts, many of the porphyry Cu-Au deposits occur in alkaline plutons. Isotopic ages indicate intrusion of host granitoid plutons and formation of associated mineral deposits from about 175 to 185 Ma in the Middle Jurassic in the Copper Mountain (North) metallogenic belt. This age represents the end of subduction-related igneous building of Quesnellia island arc, just before accretion of the Quesnellia terrane, along the with tectonically related Stikinia island arc and Cache Creek subduction-zone terranes, onto the North American Craton Margin (Monger and Nokleberg, 1996; Nokleberg and others, 2000). Copper Mountain (South) Metallogenic Belt of Porphyry Cu-Au Deposits (Belt CMS), Southern British Columbia The Copper Mountain (South) metallogenic belt of porphyry Cu-Au deposits (fig. 32; tables 3, 4) occurs in southern British Columbia and is hosted in the Copper Mountain alkalic plutonic suite in the Quesnellia island-arc terrane. The significant deposits are the Copper Mountain, Iron Mask area (Afton, Ajax), and Mt. Polley (Cariboo-Bell) porphyry Cu-Au deposits and the Lodestone Mountain zoned mafic-ultramafic Fe-V deposits (table 4) (Nokleberg and others 1997a,b, 1998). Copper Mountain (Ingerbelle) Porphyry Cu-Au Deposit The Copper Mountain (Ingerbelle) alkalic porphyry Cu-Au deposit (fig. 39) consists of mainly of chalcopyrite and bornite that occur as disseminations and in stockworks in Early Jurassic alkaline intrusive rocks of the Copper Mountain Suite and similar age volcanic and volcaniclastic rocks of the Nicola Assemblage (Preto, 1972; McMillan, 1991; P. Holbeck, Cordilleran Roundup, written commun., 1995; MINFILE, 2002). This and similar deposits in the Copper Mountain area occur along a northwest trend for over 4 km. The main ore bodies are the Copper Mountain Pits 1 to 3, Ingerbelle East, Ingerbelle, Virginia, and Alabama. Production up to 1994 was 108 million tonnes containing 770,000 tonnes Cu and 21.8 tonnes Au. Estimated reserves are 127 million tonnes grading 0.38 percent Cu, 0.16 g/t Au, and 0.63 g/t Ag (MINFILE, 2002). Estimated resources are 200 million tonnes grading 0.4 percent Cu equivalent. Significant values in Pt and Pd were reported from assays of chalcopyrite- and bornite-rich concentrates. The Copper Mountain (Ingerbelle) deposit consists of a silica-deficient, chalcopyrite-pyrite-bornite stockwork hosted almost entirely by fragmental andesitic volcanic rocks, calcareous volcaniclastic rocks and minor carbonate strata (Fahrni and others, 1976). Intrusive rocks are equigranular diorite stocks and more siliceous dikes, sills, and irregular plugs of the Lost Horse Intrusive Complex, a porphyritic unit that is often closely associated with bornite-chalcopyritepyrite-magnetite mineral deposits and occurrences. A K-Ar biotite isotopic age of 197 to 200 Ma is interpreted as an Early Jurassic age for the deposit. Alteration mineral assemblages at the Copper Mountain Pits 1 to 3 and the Alabama and Virginia ore bodies are early albite-diopside-epidote-calcite, potassium feldspar-biotite-epidote-magnetite, and a later propylitic assemblage of chlorite-pyrite-epidote-scapolite-calcite (Preto, 1972; Stanley and others, 1995). At the Ingerbelle deposit, skarn-like ore and gangue mineral zonation occurs along the contact of the Lost Horse stock where it intrudes agglomerate, tuff, tuff-breccia, and sedimentary rocks of the Nicola Assemblage (Sutherland Brown and others, 1971; Preto, 1972; Macauley, 1973; Fahrni and others, 1976; and Dawson and Kirkham, 1996). In these areas, early biotite hornfels was overprinted by prograde albite-epidote, chlorite, andradite, diopside, and sphene; both the stock and prograde skarn were then extensively replaced by retrograde albite, potassium feldspar, scapolite, calcite and hematite. Chalcopyrite-bornite ore, about 90 percent of which occurs in andesitic volcanic rocks, occurs along contacts, apophyses, and dikes of the Lost Horse stock. Iron Mask (Afton, Ajax) Porphyry Cu-Au Deposit The Iron Mask (Afton, Ajax) porphyry Cu-Au and other deposits in the Iron Mask district are hosted in the Iron Mask Batholith that consists of an Early Jurassic composite alkaline intrusion emplaced into the Nicola Group. The Ajax deposit occurs at the contact between two diorite phases of the Iron Mask pluton, a hybrid diorite and the younger Sugarloaf diorite (Ross and others, 1992, 1993; Ross and others, 1995). Pyrite, chalcopyrite, minor bornite, and molybdenite are accompanied by main-stage albite and peripheral propylitic alteration. Potassic and scapolitic alteration crosscuts albite and propylitic alteration (Ross and others, 1992, 1993, 1995). The Afton deposit consists of a tabular-shaped body of chalcopyrite and bornite that is hosted in fractured diorite of the Cherry Creek pluton. A deeply penetrating supergene zone contains native copper and lesser chalcocite. Aggregate preproduction reserves and production for the Ajax East and West deposits and for the Afton deposit are 66 million tonnes grading 0.77 percent Cu and 0.56 g/t Au. The common occurrence of picrite intrusions along faults that cut the Nicola Group and their association with the porphyry deposits in the Iron Mask pluton indicate that regional, steeply dipping faults controlled emplacement of the plutons in the batholith and also served as conduits for mineralizing fluids. An U-Pb zircon isotopic age of 207 Ma (Late Triassic) for the Cherry Creek pluton. Deep drilling in 2001-2002 southwest of and below the Afton orebody by DRC Resources Corporation has proven
a resource of 34.3 million tonnes of 1.55 percent Cu, 1.14 g/t Au, 3.42 g/t Ag and 0.125 g/t Pd in the Main Zone, and an additional 1.1 million tonnes of similar material in the Northeast Zone. The roughly tabular body is 850 m long, 750 m deep, and 70 m wide, and is open to length and depth. The deposit exhibitsboth hydrothermal and magmatic characteristics (DRC Resources Corp, news release April 2003). Smelter Lake Stock Lost Horse Intrusive Complex Ingerbelle Pit 4 4 1 2 3 5 Copper Mountain Stock Middle Eocene Princeton Group Andesitic volcanic rock Lower Cretaceous Verde Creek quartz monzonite Upper Triassic Copper Mountain Intrusions Lost Horse Complex Porphyritic microdiorite to microsyenite and breccia Contact Fault River Similkamen Pit 1 8 9 Virginia Pit Voigt Stock 10 11 Pit 2 Pit 3 6 120°30'N 7 13 14 12 Prospects & deposits 1 Duke of York 2 Oronoco 3 Honeysuckle 4 Ingerbelle East 5 Pit No. 2 West 6 Pit No. 2 East 7 Mill Zone 8 Alabama 9 June Bug 10 Connector 11 Voigt 12 P4 Zone 13 Oriole Pits 14 Oriole Copper Mountain, Voigt and Smelter Lake Stocks Syenite Monzonite Diorite Gabbro or pyroxenite 49°20'N 0 1 km Nicola Group Sedimentary and volcanic rock Figure 39. Copper Mountain (Ingerbelle) porphyry Cu-Au deposit, Copper Mountain South metallogenic belt, Canadian Cordillera. Schematic map view. Adapted from Preto and others (1972) and Stanley and others (1995). See figure 32 and table 4 for location. Late Triassic Metallogenic Belts (230 to 208 Ma; fig. 32) 93 Mt. Polley (Cariboo-Bell) Porphyry Cu-Au Deposit The Mt. Polley (Cariboo-Bell) Porphyry Cu-Au deposit consists of magnetite, chalcopyrite and minor pyrite that occur in several intrusive phases and three distinct breccias in an Early Jurassic pseudoleucite-bearing alkaline complex that intrudes Upper Triassic Nicola alkaline volcanic and volcaniclastic rocks of the Quesnel trough (EMR Canada, 1989; McMillan, 1991; Mining Review, 1991; Gosh, 1992; Fraser and others, 1993; MINFILE, 2002). Some skarn and vein occurs in tuff and flows of the Nicola Assemblage. Supergene mineralization includes malachite, native copper, cuprite, chalcocite and covellite. The deposit contains proven reserves of 76.5 million tonnes grading 0.30 percent Cu, 0.47 g/t Au. Production through 1999 was 15.26 million tonnes with 341,000 g Ag, 6,858,448 g Au, and 31, 637,173 kg Cu (MINFILE, 2002). A U-Pb zircon isotopic age of 200 ± 1.5 Ma for diorite and a monzonite porphyry indicates an Early Jurassic age for intrusion of the host granitoid rocks. Lodestone Mountain Zoned Mafic-Ultramafic Fe-Ti Deposit The Lodestone Mountain zoned mafic-ultramafic Fe-Ti deposit consists of titaniferous magnetite and ilmenite that occur in pods and lenses and as disseminated grains in pyroxenite of the Tulameen zoned mafic-ultramafic (Alaskan type) complex (St. Louis and others, 1986; Nixon and others, 1997). The deposit contains estimated reserves of 81.65 million tonnes grading 17.56 percent Fe (EMR Canada, 1989). Minor Pt and Pd are reported. Reported Ti content of magnetite is 1 percent. An additional 249 million tons of possible and inferred ore is estimated. The deposit is interpreted as forming primarily by magmatic differentiation. The Late Triassic Tulameen layered mafic-ultramafic (Alaskan-type) complex is coeval and in part cogenetic with adjacent gabbro plutons of the Lost Horse intrusive complex (Findlay, 1969). The complex intrudes basaltic andesite of the Nicola Group. Several lode and placer Pt-Pd deposits occur at Grasshopper Mountain in the Tulameen Complex (Findlay, 1969). Origin of and Tectonic Controls for Copper Mountain (South) Metallogenic Belt The Copper Mountain (South) metallogenic belt is hosted in the Copper Mountain plutonic suite. Syenite, monzonite, and monzodiorite are most common, but diorite, monzogranite, clinopyroxenite occur locally. The porphyry Cu-Au deposits are hosted in the felsic plutons, whereas the major Fe-Ti deposit at Lodestone Mountain is hosted in zoned mafic-ultramafic rocks. Many felsic plutons are lithologically and texturally complex, with multiple phases of intrusion and potassic metasomatism, characterized by abundant apatite and magnetite. Some plutons are nepheline and leucite normative; others are both quartz saturated and quartz undersaturated (Woodsworth and others, 1991). The deposits in the Copper Mountain (South) and (North) metallogenic belts are part of the subduction related Quesnellia island arc (Monger and Nokleberg, 1996; Nokleberg and others, 2000). In both the Copper Mountain (North) and Copper Mountain (South) metallogenic
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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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Page 75 and 76: (Ryazantzeva and Shurko, 1992). The
Page 77 and 78: tonnes Au and an average grade of a
Page 79 and 80: mafic and felsic metavolcanic rocks
Page 81 and 82: intrusion from about 402 to 366 Ma
Page 83 and 84: Origin of and Tectonic Controls for
Page 85 and 86: mentary rocks of the Cambrian to De
Page 87 and 88: (Preto and Schiarizza, 1985; Schiar
Page 91 and 92: ate and clastic rocks and volcanicl
Page 93 and 94: (Nokleberg and others, 1994c, 1997c
Page 95 and 96: Berezovka River Metallogenic Belt o
Page 99 and 100: Finlayson Lake Metallogenic Belt of
Page 101 and 102: and barite in siliceous black turbi
Page 103 and 104: Windermere Creek (Western Gypsum) C
Page 105 and 106: (NX, DL, MY), Viliga (VL), and Zolo
Page 107 and 108: South of the main east-west-trendin
Page 109 and 110: ated subduction zone in the Wrangel
Page 111 and 112: icite-biotite-quartz bodies in frac
Page 113 and 114: Canada Cordillera. The granitoid ro
Page 115 and 116: Viliga (VL) passive continental-mar
Page 117 and 118: 32; tables 3, 4) occurs along the n
Page 119 and 120: superterrane, consists mainly of ma
Page 121 and 122: ers, 1994c, 1997c). In southern Bri
Page 123: mental volcanic rocks of intermedia
Page 127 and 128: potassic zone. Combined estimated p
Page 129 and 130: and quartz monzodiorite stock and s
Page 131 and 132: and Omolon (OM) cratonal terranes,
Page 133 and 134: in volcanic and volcaniclastic rock
Page 135 and 136: minor calcite, and sporadic pyrite
Page 137 and 138: supergene blanket are interpreted a
Page 139 and 140: deposits and occurrences consist of
Page 141 and 142: onto the Omulevka terrane to form t
Page 143 and 144: superterrane. This belt is interpre
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Page 147 and 148: quartz, and is virtually not associ
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
Page 155 and 156: in a island arc that was tectonical
Page 157 and 158: and Early Cretaceous Koyukuk island
Page 159 and 160: The deposit consists of disseminate
Page 161 and 162: The Orange Hill deposit contains an
Page 163 and 164: 49; tables 3, 4) (Foley and others,
Page 165 and 166: locally Late Triassic marine volcan
Page 167 and 168: gold in a gangue of quartz, calcite
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
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during hypogene and supergene alter
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collision and regional thrusting, t
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Yur Au Quartz Vein Deposit The smal
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phase has a Rb-Sr isotopic age of 1
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sian Northeast. The belt is hosted
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Host Granitoid Rocks and Associated
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that are up to 600-1,500 m long, av
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Metallogenic Belts Formed During La
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y partly coeval plutons that range
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tion is interpreted as occuring by
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the Badzhal-Ezop and Khingan parts
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and comagmatic with volcanic rocks;
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as interpreted for the Rock Creek d
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source (Yeo, 1992). The Blow River
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2000). The spatial location of the
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to the east in the central Yukon Te
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occur in a 30-km-long belt along ir
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The Emerald deposit has produced ap
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Metallogenic-Tectonic Model for Ear
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cham oceans were closed, and the Ch
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greisenized Mesozoic granite that i
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composition magmatic bodies (with a
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Origin of and Tectonic Controls for
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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
Page 331 and 332:
Cordilleran Orogen in Canada: Geolo
Page 333 and 334:
Goldfarb, R., Hart, C., Miller, M.,
Page 335 and 336:
Grove, E.W., 1986, Geology and mine
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Høy, T., 1982a, Stratigraphic and
Page 339 and 340:
Jones, D.L., Silberling, N.J., Cone
Page 341 and 342:
Kutyev, F. Sh., Baikov, A.I., Sidor
Page 343 and 344:
Shield—Ultramafic magma and its m
Page 345 and 346:
Manns, F.T., 1981, Stratigraphic as
Page 347 and 348:
Miller, M.L., and Bundtzen, T.K., 1
Page 349 and 350:
Mortimer, N., 1987, The Nicola Grou
Page 351 and 352:
Noble, S.R., Spooner, E.T.C., and H
Page 353 and 354:
Canada Annual Meeting, Saskatoon, S
Page 355 and 356:
Perello, J.A., Fleming, J.A., O’K
Page 357 and 358:
Far East—Mineralogical criteria f
Page 359 and 360:
Roeske, S.M., Mattinson, J.M., and
Page 361 and 362:
Schmidt, J.M., and Zierenberg, R.A.
Page 363 and 364:
formation occurrences: Materialy po
Page 365 and 366:
Struik, L.C., 1986, Imbricated terr
Page 367 and 368:
Valuy, G., and Rostovsky, F., 1988,
Page 369 and 370:
Wolfe, W.J., 1995, Exploration and
Page 371 and 372:
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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