USGS Professional Paper 1697 - Alaska Resources Library

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274 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera Peninsula and Aleutian Islands (AP) metallogenic belt, which contains granitic-magmatism-related deposits and is hosted in the Aleutian volcanic belt. (11) Offshore of the southern Canadian Cordillera, seafloor spreading continued along the Juan de Fuca Oceanic ridge (JFF). Northward movement of the Pacific oceanic plate (PAC) and associated transform displacement on the Queen Charlotte transform fault (QC) resulted in continued northward migration and subduction of the Yakutat terrane (YA) beneath the continental margin of southern Alaska. (12) To the south, the Cascade continental-margin arc continued activity. Associated with this arc was continued subduction of part of the Juan de Fuca Plate (JF) along the ancestor of the modern Cascadia megathrust (CC). Regional extension, associated with back-arc spreading the behind Cascade arc (ca ), resulting in continental eruption of the Columbia River basalt (cr; Wells and Heller, 1988; England and Wells, 1991). Continuing on from the early Tertiary in the Cascade arc was the was the Owl Creek (OC) metallogenic belt, which contains granitic-magmatism-related deposits, and is interpreted during subduction-related granitic plutonism. 60 o NSC NSV KK MY GK ? eb Metallogenic Belts Formed in Tertiary Continental-Margin Arcs, Kamchatka Peninsula, Southern Alaska, and Southern Canadian Cordillera East Kamchatka Metallogenic Belt of Au-Ag Epithermal Deposits (Belt EK), Eastern and Southern Kamchatka Peninsula The East Kamchatka metallogenic belt of Au-Ag epithermal deposits (fig. 125; tables 3, 4) occurs in the eastern and southern parts of the Kamchatka Peninsula. The deposits are hosted in the East-Kamchatka volcanic belt that overlies late Mesozoic and Cenozoic island-arc and terranes of accretionarywedge terranes (Pozdeev, 1990). The Au-Ag epithermal deposits, most of that are economic or are potentially economic, are associated mainly with Miocene volcanoes, hypabyssal bodies, and small intrusions. The significant deposits in the belt are at Asachinskoe, Kitkhoi, Kumroch, Mutnovskoe, and Rodnikovoe (table 4) (Nokleberg and others 1997a,b, 1998). The Au-Ag epithermal vein deposits in the East Kamchatka metallogenic belt are interpreted as forming in two LO (am) ab 180 o ?? ? ab NF ? KA 80 o cb AL DE NAC COLLAGE OF RIFTED TERRANES COLL COLL SEA OF JAPAN RIFT sp COLL OT COLL NAM OKHOTSK SEA RIFT wr COLL cr sj ej KUK kr ku kk kc, ek, ck, wk EK, CK KM atb AP COLL al YAK ca EX JF OC cr 0 800 km NORTHEAST ASIA ARC PAC al PW ALEUTIAN- WRANGELL ARC PAC JFR ? ca 0 800 mi 20 to 10 Ma CASCADE ARC TI METALLOGENIC BELTS AP - Alaska Peninsula and Aleutian Islands CK - Central Kamchatka EK - East Kamchatka OC - Owl Creek OT - Olyutor Figure 127. Middle Tertiary (Miocene—20 to 10 Ma) stage of metallogenic-tectonic model for the Russian Far East, Alaska, and the Canadian Cordillera and adjacent offshore areas. Refer to text for explanation of metallogenic-tectonic events, to tables 3 and 4 for descriptions metallogenic belts and significant deposits, and to figure 18 for explanation of abbreviations, symbols, and patterns. Adapted from Nokleberg and others (1997b, 1998, 2000). QC ? NAC CC
stages (Petrenko, 1999): (1) In the early Miocene, Au-Ag (± Zn, Pb) epithermal vein and stockwork deposits, as at Mutnovskoe, Kumroch, and Kitkhoi, formed during eruptions of intermediate and felsic volcanic rocks and during formation of small diorite-granodiorite intrusions (Lattanzi and others, 1995). The major metals are Au, Pb, and Zn, along with Ag and sulfosalts. (2) In the late Miocene, Au quartz-adularia epithermal vein deposits, as at Rodnikovoe and Asacha deposits, formed in andesite-basaltic piles associated with hypabyssal bodies, and in mafic, intermediate, and felsic dikes. The deposits are sulfide poor and are associated with propyllitic alteration. Some of the deposits may be Pliocene; however, K- Ar isotopic studies of stockworks, dikes, and adularia-quartz veins yield ages of 12 to 5 Ma, indicating a Miocene age. The association of sulfide-rich and sulfide-poor epithermal deposits in the East Kamchatka metallogenic belt suggests diverse volcanic processes (Pozdeev, 1990; Lattanzi and others, 1995). A recent study by Takahashi and others (2002) presents a 4-fold classification of epithermal Au-Ag mineralization in Kamchatka—(1) Late Cretaceous Okhotsk-Chukotka Belt (Sergeevka deposit), (2) the middle Tertiary Koryak-Western Kamchatka Belt (including the Ametistovoe deposit with a K-Ar isotopic age of 41.4 Ma), (3) the late Tertiary Central Kamchatka belt (including the Zolotoy deposit with a K-Ar isotopic age of 17.1 Ma, and the Aginskaya deposit with a K-Ar isotopic age of 6.9 Ma), and (4) the Eastern Kamchatka belt (including the Asachinskoye, Mutnovskoe, Rodnikovoe, and Porozhistovoe deposits with K-Ar isotopic ages 7.4 to 0.9 Ma). An overview of the major Au-Ag epithermal vein deposits of the Kamchatka was published by Petrenko (1999). AsachinskoeAu-Ag Epithermal Vein Deposit The AsachinskoeAu Au-Ag epithermal vein deposit (Shchepot’ev, 1989; I.D. Petrenko, written commun., 1991; A.I. Pozdeev, written commun., 1991; Petrenko, 1999;Okrugin and others, 2002) consists of a zone of quartz-adularia veins that occur along a north-south trending, strike-slip fault. Veins split and pinch out in tuff and andesitic lava. Ore body is a nearly flat-lying band, gently dipping to the south, and conformable to the hypabyssal host rocks. Ore exhibits colloformbanded structure. Ore minerals are less than 1 percent of the veins. Ore mineral assemblages are: gold-hydromica, goldnaumanite-polybasite, and gold-adularia-quartz. Major ore minerals are pyrite, gold, selenium polybasite, and naumanite. Deposit occurs in center of a hypabyssal dacite dome at the intersection of three large linear faults. Deposit associated with hypabyssal volcanic rocks that are inferred in cross-section. A K-Ar isotopic age for the deposit is 4 Ma (Takahashi and others, 2001). The deposit is medium size with as much as 20 g/t Au and 40 to 50 g/t Ag. Estimated reserve are 1.56 million tonnes averaging 35 g/t Au and 62 g/t Ag. Mutnovskoe Au-Ag Epithermal Vein Deposit The Mutnovskoe Au-Ag epithermal vein deposit (Shchepot’ev, 1989; I.D. Petrenko, written commun., 1991; Middle Tertiary Metallogenic Belts (20 to 10 Ma) (figs. 125, 126) 275 Lattanzi and others, 1995; Petrenko, 1999;Okrugin and others, 2002) occurs in the central part of a paleovolcano composed of Oligocene-Miocene mafic- and intermediate-composition volcanic rocks. Plutonic rocks consist of Miocene diorite intrusions and numerous dikes of varied composition. Major ore zone consists of a thick vein and some apophyses with zones of quartz veinlets between them. Drilling indicates that ore extends to a depth of 500 m below the surface. In heavily weathered zones, generally at the southern flank of the deposit, quartz veins contain from 10 to 18 percent sulfides. On the less weathered northern flank, the deposit is sulfide-poor and contains 0.2 to 2 percent base metals. The major ore assemblages are gold- tennantite-tetrahedrite, gold-argentite-pearsite, and chlorite-galenasphalerite. Canfieldite, as well as the telluride minerals, hessite and altaite, also occur. The deposit is vertically zoned, with gold, tennantite, and tetrahedrite occurring in the upper part of the veins and chalcopyrite, galena, and sphalerite occurring in the lower part of the veins. The K-Ar age of mineralization for the north flank of the Mutnovskoe deposit is 3.3 Ma and 1.1 Ma for the south flank of the deposit (Takahashi and others, 2001). The deposit is of medium size. Average grades are as much as 3 g/t Au and 10 g/t Ag. Proven reserves are to the north are 1.8 million tonnes of ore averaging 16 g/t Au and 315 g/t Ag, and to the south are 5.2 million tonnes of ore averaging 12.4 g/t Au, 1,300 g/t Ag, and 69,000 tonnes combined Pb and Zn. The deposit contains an estimated resource of about 20 tonnes Au. Rodnikovoe Au Quartz-Adularia Epithermal Vein Deposit The Rodnikovoe Au quartz-adularia epithermal vein deposit (I.D. Shchepot’ev, 1989; D. Petrenko, written commun., 1991; Petrenko, 1999) consists of a major vein and related quartz and quartz-carbonate veins and veinlets that cut the apical part of a gabbro-diorite intrusion. In addition to gold, the veins and veinlets contain goldfieldite, silver sulfosalts, and argentite. Gold fineness is 400 to 600. Alteration includes propylitic (chlorite-carbonate and epidote-chlorite facies), kaolinitic, quartz-hydromica alteration with montmorillonite, and silicic with quartz and pyrite. The altered rocks are laterally zoned. The ore occurs in a complex vein system with several funnel-shaped ore shoots that narrow with depth. The shoots dip 30 to 50° south. The vertical extent of mineralization is less than 150 m. High Au concentrations (25-30 g/t Au) occur in upper levels of ore bodies. The quartz-adularia veins are Late Miocene with K-Ar ages of approximately 0.9 to 1.1 Ma (Takahashi and others, 2001). The deposit is of medium size. Average grades are as much as 11.3 g/t Au and 40 to 50 g/t Ag. The estimated reserves are 40 tonnes gold and 356 tonnes silver with an average grade of 11.0 g/t Au and 98.0 g/t Ag. Origin of and Tectonic Controls for East Kamchatka Metallogenic Belt The Central Kamchatka volcanic belt that hosts the East Kamchatka metallogenic belt consists chiefly of Eocene to Quaternary thick, gently dipping andesite, dacite, and rhyolite strata, which are interlayered with sandstone, siltstone, and
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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
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deposits are at Terrassnoe and Kuna
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Peschanka Porphyry Cu-Mo Deposit Th
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The belt is hosted in the Late Jura
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in a island arc that was tectonical
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and Early Cretaceous Koyukuk island
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The deposit consists of disseminate
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The Orange Hill deposit contains an
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49; tables 3, 4) (Foley and others,
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locally Late Triassic marine volcan
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gold in a gangue of quartz, calcite
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Verkhoyansk granite belt, which int
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metallogenic belts are interpreted
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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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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
Page 255 and 256: Eastern Asia-Arctic Metallogenic Be
Page 257 and 258: groups of deposits are interpreted
Page 259 and 260: Indian Mountain and Purcell Mountai
Page 261 and 262: and southeastern Alaska (Moll and P
Page 263 and 264: Nokleberg and others, 1995a; Bundtz
Page 265 and 266: g/t Au or 368.2 Au gold. The deposi
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Page 269 and 270: Mount Nansen porphyry Cu-Mo deposit
Page 271 and 272: A Map 450 500 550 Cross section Dik
Page 273 and 274: Cretaceous and early Tertiary conti
Page 275 and 276: deposits, at Chichagoff and Hirst-C
Page 277 and 278: others, 1994c, 1997c). The signific
Page 279 and 280: tonnes grading 0.53 percent Ni, 0.3
Page 281 and 282: with a 0.25 percent cut-off. The de
Page 283 and 284: Bulkley Metallogenic Belt of Porphy
Page 285 and 286: Red Rose W-Au-Cu-Ag Polymetallic Ve
Page 287 and 288: ish Columbia and consists of severa
Page 289 and 290: during back-arc extension or transt
Page 291 and 292: stocks and dikes, is associated wit
Page 293 and 294: etrograde minnesotaite (Fe talc), F
Page 295 and 296: Specific Events for Early to Middle
Page 297 and 298: of fractured and faulted Permian-Tr
Page 299 and 300: sists of a mineralized fracture zon
Page 301 and 302: dolomite. Wall rock alteration incl
Page 303 and 304: elt of late Tertiary plutons that a
Page 305: plates that exhibit magnetic anomal
Page 309 and 310: mon. The deposit is of medium size
Page 311 and 312: Metallogenic-Tectonic Model for Lat
Page 313 and 314: The origin of the Hg deposits of th
Page 315 and 316: margin or island-arc tectonic envir
Page 317 and 318: Columbia: Implicatons for the Middl
Page 319 and 320: Bazard, D.R., Butler, R.F., Gehrels
Page 321 and 322: Bradley, D.C., Haeussler, P.J., and
Page 323 and 324: Bundtzen, T.K., Laird, G.M., Caluti
Page 325 and 326: Cecile, M.P., 1982, The lower Paleo
Page 327 and 328: Debari, S.M., and Coleman, R.G., 19
Page 329 and 330: 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
Page 337 and 338: 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
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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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