USGS Professional Paper 1697 - Alaska Resources Library

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168 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera terrane (Arctic Alaska superterrane) and the Coldfoot terrane to the south (Nokleberg and others, 1994c, 1997c). The significant deposits are at Little Squaw and Mikado in the Chandalar district (table 4) (Nokleberg and others 1997a,b, 1998). Recent work on Au-bearing quartz vein deposits in the Wiseman area is summarized by Eden (2000). Mikado Au Quartz Vein Deposit The Mikado Au quartz vein deposit (Chipp, 1970; DeYoung, 1978; Dillon, 1982; Ashworth, 1983; J.T. Dillon, oral commun., 1986; Rose and others, 1988) consists of several quartz veins as much as 3 m thick in a zone about 4.0 km long and 1.6 km wide. The veins contain scattered minor arsenopyrite, galena, sphalerite, stibnite, and pyrite and sparse gold. The veins occur along steeply dipping normal faults in Devonian or older quartzmuscovite schist, phyllite, and quartzite. The Little Squaw Mining Company drove more than 1,000 m of underground workings from 1980 to 1983. Minor production and several episodes of exploration activity have occurred, notably during the 1920’s and 1960’s. The Mikado deposit contained an estimated 12,000 tonnes averaging 75 g/t Au and produced about 542 kg Au from ore averaging about 30 g/t Au (Bundtzen and others, 1994). The Mikado deposit and surrounding district contains an estimated remaining 45,000 tonnes grading 30 g/t Au. Origin of and Tectonic Controls for Southern Brooks Range Metallogenic Belt The Au quartz vein deposits occur along steeply dipping normal faults in greenschist facies metasedimentary rocks that are part of a structurally complex, polymetamorphosed, and polydeformed assemblage of Devonian or older carbonate rocks, including the Skajit Limestone, calc-schist, quartz-mica schist, and quartzite, which are intruded by Proterozoic and Late Devonian gneissic granitoid rocks. These early Paleozoic metasedimentary rocks and Devonian metagranitoid rocks form a major part of the Hammond passive continental-margin terrane of the Arctic Alaska superterrane (Jones and others, 1987; Moore and others, 1992). Field relations indicate the deposits, which were deposited from hydrothermal fluids, were deposited during normal faulting. The normal faulting may be associated with a period of regional extension that was associated with the waning stages of greenschist facies regional metamorphism and companion penetrative deformation in the Early to mid-Cretaceous (Moore and others, 1992; Nokleberg and others, 1994c, 1997c). This period of regional metamorphism is interpreted as the last major metamorphic event in the Hammond and Coldfoot terranes. In a few areas, the Coldfoot and Hammond terranes exhibit relict blueschist facies minerals that are interpreted as forming in a Jurassic or older period of convergent deformation and metamorphism (Moore and others, 1994). The convergent deformation and blueschist facies metamorphism probably occurred during Late Jurassic and Early Cretaceous subduction of the Coldfoot and Hammond terranes under the Angayucham subduction-zone terrane, and Koyukuk island-arc terrane to the south (Moore and others, 1994; Patton and others, 1994; Plafker and Berg, 1994; Nokleberg and others, 2000). As in the Nome region, the regional blueschist facies metamorphism was followed by (1) thrusting on oceanic units of the Angayucham terrane onto the Coldfoot and Hammond terranes and other parts of the passive continental-margin arctic Alaska superterrane, and (2) extensional, Early to mid-Cretaceous retrograde greenschist metamorphism and formation of Au quartz vein deposits (Armstong and others, 1986; Moore and others, 1994; Till and Dumoulin, 1994). The Au quartz vein deposits of the Southern Brooks Range metallogenic belt only occur in a small portion of the greenschist facies metasedimentary rocks of the southern Brooks Range. However, the more extensive placer Au deposits along the Brooks Range may be derived from undiscovered or now totally eroded Au quartz vein deposits. The Au quartz vein deposits in the Southern Brooks Range metallogenic belt are interpreted as coeval with the Nome metallogenic belt to the southwest. Fish River Metallogenic Belt of Sedimentary P and Fe Deposits (Belt FR), Northern Yukon Territory The Fish River metallogenic belt of sedimentary P and Fe deposits occurs in the northern Yukon Territory (fig. 62; tables 3, 4) (Nokleberg and others, 1997b, 1998)and is hosted in the Early Cretaceous Blow River Formation. The significant deposits are at Big Fish River and Alto. The Fish River metallogenic belt is herein tentatively interpreted as forming during Late Mesozoic dextral movement along the Kaltag-Porcupine fault system. The Fish River (Big Fish, Boundary, Rapid) stratabound Fe-P deposit consists of siderite and phosphatic ironstone that occur in shale in an Early Cretaceous (Albian) clastic wedge (Yukon Minfile, 1988; Butrenchuk, 1996). The ironstone consists of phosphate-siderite pellets and granules in a matrix of detrital quartz and mudstone. Rare phosphate minerals occur in epigenetic fracture veins and to a lesser degree in vugs, bedding plane partings, and fault breccia. The deposit is the well-known type locality of lazulite, the official Yukon gemstone. Estimated resources are more than 1 billion tonnes grading 40 percent Fe. The Alto oolitic magnetite iron formation is hosted in black shale of the Jurassic and Cretaceous Kingak Formation (Norris, 1976; Yukon Minfile, 1987). The deposit consists of olitic magnetite that occurs in a 45-m-thick bed, which occurs for a strike length of 350 m, and is part of a recessive-weathering black shale that is about 50 m above the base of the Kingak Formation. Estimated resources are 50 million tonnes grading 55 percent Fe (Norris, 1976). The Early Cretaceous Blow River Formation is part of a thick clastic wedge deposited in the Blow Trough, which is interpreted as forming during late Mesozoic, dextral movement along the Kaltag-Porcupine Fault system (Norris and Yorath, 1981). The sideritic ironstone and phosphorites are interpreted to be distal, reworked deep water pellet packstone deposits within a thick silt and conglomerate unit with a westerly clastic
source (Yeo, 1992). The Blow River Formation contains an estimated P 2O 5 resource of approximately 7 billion tonnes, in addition to a larger resource of low-grade iron ore Young (1977a,b). Metallogenic Belts Formed in Late Mesozoic Collision and Accretion of Wrangellia Superterrane, and Generation of Omineca-Selwyn Plutonic Belt, Canadian Cordillera Selwyn Metallogenic Belt of W-Cu Skarn, Zn-Pb- Ag Skarn, and Zn-Pb-Ag Manto Deposits, Eastern and Northeastern Yukon Territory (Belt SW) The Selwyn metallogenic belt W-Cu skarn, Zn-Pb-Ag skarn, and Zn-Pb-Ag manto deposits (fig. 62; tables 3, 4) occurs in the eastern and northeastern Yukon Territory and consists primarily of an arcuate belt of W-Cu (Zn-Mo) skarns and Zn- Pb-Ag (Cu-W) skarns and manto deposits, which are hosted in or near the related granitoid stocks of the mid-Cretaceous Selwyn Plutonic Suite (Anderson, 1983b). This suite is part of the Omineca-Selwyn plutonic belt, which extends from Open Pit Orebody Lower Cambrian Dolomite Argillite Quartzite Upper Argillite Ore Limestone Swiss Cheese Limestone Upper Proterozoic - Lower Cambrian Lower Argillite Mine Stock Sekwi Formation Vampire Formation Late Early Cretaceous Metallogenic Belts (120 to 100 Ma; figs. 61, 62) 169 southeastern Yukon Territory and southwestern Northwest Territories northwestward into the Mayo district. The major W skarn deposits are at Bailey (Pat), Canada Tungsten (Cantung), Lened (Rudi, Godfrey), MacTung (MacMillan Tungsten), and the major Pb-Zn skarn and manto deposits are at Sa Dena Hes (Mt. Hundere), McMillan (Quartz Lake), and Prairie Creek (Cadillac; table 4) (Nokleberg and others 1997a,b, 1998). Other potentially economic skarn tungsten deposits in the belt include, from southeast to northwest, Bailey with an estimated resource of 405,454 tonnes grading 1.0 percent WO 3, Baker- Lened with an estimated resource of 750,000 tonnes grading 1.2 percent WO 3, and Clea (Dawson, 1996c). Canada Tungsten (Cantung) W Skarn Deposit The Canada Tungsten (Cantung) W skarn deposit (fig. 76) consists of pyrrhotite, scheelite and chalcopyrite with minor sphalerite in diopside skarn bodies that replace two members of Early Cambrian limestone (Sinclair, 1986; EMR Canada, 1989; Yukon Minfile, 1990; Dawson and others, 1991). The host rocks are the Cambrian to Devonian part of the North American Continental Margin. The skarns are related to intrusion of a Late Cretaceous quartz monzonite S N E-Zone Orebody Fault Contact 0 100 m Figure 76. Canada Tungsten W skarn deposit, Selwyn metallogenic belt, Canadian Cordillera. Schematic cross section. Adapted from Gordey and Anderson (1993). See figure 62 and table 4 for location.
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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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Canada Cordillera. The granitoid ro
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Viliga (VL) passive continental-mar
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32; tables 3, 4) occurs along the n
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superterrane, consists mainly of ma
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ers, 1994c, 1997c). In southern Bri
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mental volcanic rocks of intermedia
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a resource of 34.3 million tonnes o
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potassic zone. Combined estimated p
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and quartz monzodiorite stock and s
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and Omolon (OM) cratonal terranes,
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in volcanic and volcaniclastic rock
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minor calcite, and sporadic pyrite
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supergene blanket are interpreted a
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deposits and occurrences consist of
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onto the Omulevka terrane to form t
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superterrane. This belt is interpre
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to form along the leading edge of t
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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
Page 175 and 176: during hypogene and supergene alter
Page 177 and 178: collision and regional thrusting, t
Page 179 and 180: Yur Au Quartz Vein Deposit The smal
Page 181 and 182: phase has a Rb-Sr isotopic age of 1
Page 183 and 184: sian Northeast. The belt is hosted
Page 185 and 186: Host Granitoid Rocks and Associated
Page 187 and 188: that are up to 600-1,500 m long, av
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
Page 197 and 198: and comagmatic with volcanic rocks;
Page 199: as interpreted for the Rock Creek d
Page 203 and 204: 2000). The spatial location of the
Page 205 and 206: to the east in the central Yukon Te
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
Page 213 and 214: cham oceans were closed, and the Ch
Page 215 and 216: greisenized Mesozoic granite that i
Page 217 and 218: composition magmatic bodies (with a
Page 219 and 220: Origin of and Tectonic Controls for
Page 221 and 222: to Albian pelecypods (Nokleberg and
Page 223 and 224: quartz-arsenopyrite-pyrrhotite, pol
Page 225 and 226: thermally altered to siliceous and
Page 227 and 228: These ore bodies are as much as 1 m
Page 229 and 230: Eastern Asia-Arctic Metallogenic Be
Page 231 and 232: Demin, and Krasilnikov, 1974; Nekra
Page 233 and 234: 10 percent Cu, as much as 0.92 perc
Page 235 and 236: pyrite, pyrite, galena, sphalerite,
Page 237 and 238: content decreases with depth, as do
Page 239 and 240: azdelnoye, (2) porphyry Sn deposits
Page 241 and 242: Karalveem Au Quartz Vein Deposit Th
Page 243 and 244: Democrat (Mitchell Lode) Granitoid-
Page 245 and 246: with high-temperature and high-pres
Page 247 and 248: chalcocite and covellite and also h
Page 249 and 250: 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
Page 339 and 340:
Jones, D.L., Silberling, N.J., Cone
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Kutyev, F. Sh., Baikov, A.I., Sidor
Page 343 and 344:
Shield—Ultramafic magma and its m
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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
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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
Page 357 and 358:
Far East—Mineralogical criteria f
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Roeske, S.M., Mattinson, J.M., and
Page 361 and 362:
Schmidt, J.M., and Zierenberg, R.A.
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formation occurrences: Materialy po
Page 365 and 366:
Struik, L.C., 1986, Imbricated terr
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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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