USGS Professional Paper 1697 - Alaska Resources Library

More documents

Recommendations

Info

124 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera Metallogenic Belts Formed in Late Mesozoic Koyukuk and Togiak Island Arc Systems in Western and Southwestern Alaska Eastern Seward Peninsula and Marshall Metallogenic Belt of Podiform Cr Deposits (Belt ESM), Northwestern Alaska The Eastern Seward Peninsula and Marshall metallogenic belt of podiform Cr deposits occurs in the eastern Seward Peninsula and in the Marshall (Andreatsky River) area to the south in northwestern Alaska (fig. 49; tables 3, 4) (Nokleberg and others, 1997b, 1998). No significant lode deposits are known from the belt, but small, isolated occurrences of nickel sulfide minerals are found in ultramafic rocks in the region. These occurrences are interpreted as the sources of PGE minerals that have been recovered in placer mines in Sheep Creek and Dime Creek, and in the Ungalik River in the Koyuk district. The metallogenic belt is hosted in a complexly deformed, fault-bounded unit of ophiolite and related rocks that occur discontinuously in five small areas (Foley and others, 1982). In the eastern Seward Peninsula area, the units consists of fault-bounded slivers of ultramafic rocks and serpentinite that occur along the tectonic boundary between the Koyukuk island-arc terrane to the east and the Seward metamorphosed continental-margin terrane to the west (Nokleberg and others, 1997b, 1998). In the Marshall (Andreatsky River) area, the unit consists of pillow basalt, chert, diorite, gabbro, serpentinite, and harzburgite. In both areas, the ophiolite and related rocks are interpreted as small, isolated klippen or faulted slivers of the upper part of the Angayucham oceanic and subduction-zone terrane. The thrust slices of ultramafic rocks in the highest structural level of the Angayucham terrane are interpeted to be the lower part of an ophiolite that consitutes the base of the Koyukuk island arc (Loney and Himmelberg, 1989, Patton and Box, 1989). This interpretation suggests that the Eastern Seward Peninsula and Marshall metallogenic belt of podiform Cr deposits formed during subduction-related intrusion of mafic-ultramafic plutons into the basal part of the Late Jurassic Koyukuk island arc (Nokleberg and others, 1993; Goldfarb, 1997; Nokleberg and others, 2000). Kobuk Metallogenic Belt of Podiform Cr Deposits (Belt KB), Northern Alaska The Kobuk metallogenic belt of podiform Cr and associated PGE deposits, and one serpentine-hosted asbestos deposit (fig. 49; tables 3, 4), occurs for several hundred kilometers along the southern flank of the Brooks Range in northern Alaska. The metallogenic belt is hosted in the upper structural of the Angayucham oceanic and subduction-zone terrane (Jones and others, 1987; Nokleberg and others, 1994c, 1997c), which is interpreted as the basal part of the Koyukuk island arc (Patton and others, 1994). The major podiform Cr deposits are at Iyik- rok Mountain, Avan, Misheguk Mountain, and Siniktanneyak Mountain (table 4) (Nokleberg and others 1997a,b, 1998). The serpentine-hosted asbestos deposit is at Asbestos Mountain. Misheguk Mountain Podiform Cr Deposit The Misheguk Mountain Podiform Cr deposit (Roeder and Mull, 1978; Degenhart and others, 1978; Zimmerman and Soustek, 1979; Foley and others, 1984, 1982, 1997) consists of disseminated fine- to medium-grained chromite in Jurassic or older locally serpentinized dunite and peridotite tectonite. The dunite and harzburgite layers are intensely deformed into minor folds. Grab samples contain as much as 27.5 percent Cr and 0.31 g/t PGE, and the deposit contains an estimated 110,000 to 320,000 tonnes chromite. Chromite-bearing zones have surface dimensions of 31 by 107 m. The deposit is interpreted as part of a dismembered ophiolite. Avan Podiform Cr Deposit The Avan podiform Cr deposit (Roeder and Mull, 1978; Degenhart and others, 1978; Zimmerman and Soustek, 1979; Mayfield and others, 1983; Foley and others, 1985, 1982) consists of disseminated fine- to medium-grained chromite in Jurassic or older dunite and harzburgite tectonite that is locally altered to serpentinite. Zones of chromite in dunite are as much as a few meters wide and a few hundred meters long; the host dunite and harzburgite layers exhibit intense minor folds. Grab samples contain as much as 43 percent Cr and 0.48 g/t PGE. The deposit contains an estimated 290,000 to 600,000 tonnes chromite. The dunite and harzburgite tectonite host rocks at Avan and elsewhere occur as fault-bounded slabs in the Misheguk igneous sequence that also contains pillow basalt, gabbro, chert, and minor limestone (Roeder and Mull, 1978; Zimmerman and Soustek, 1979; Nelson and Nelson, 1982; Foley and others, 1982). The age of the ultramafic rocks hosting the podiform Cr deposits is probably Jurassic (Patton and others, 1994). This sequence is part of the Angayucham subductionzone terrane (Patton and others, 1994). The ultramafic rocks hosting the Asbestos Mountain deposit also occur as faultbounded slabs in the upper part of the Angayucham terrane. Origin of and Tectonic Controls for Kobuk Metallogenic Belt The Kobuk metallogenic belt occurs in highly deformed mafic and ultramafic rock that forms the upper structural level of the Angayucham subduction-zone terrane along the southern margin of the Brooks Range (fig. 49; tables 3, 4). The belt occurs mainly in a major east-west-striking, southdipping thrust sheet, which extends for several hundred km, and in sparse isolated klippen. These Angayucham terrane occurs along south-dipping faults over the highly deformed metamorphosed, middle Paleozoic and older metasedimentary, metavolcanic, and lesser metagranitoid rocks of the Coldfoot metamorphosed continental-margin terrane to the north and in turn are overthrust by the mainly island-arc, Late Jurassic
and Early Cretaceous Koyukuk island-arc terrane to the south (Moore and others, 1992; Patton and others, 1994). The thrust slices of ultramafic rocks in the highest structural level of the Angayucham terrane are interpeted lower part of an ophiolite that consitutes the base of the Koyukuk island arc (Loney and Himmelberg, 1989, Patton and Box, 1989; Patton and others, 1994). This interpretation suggests that the Kobuk metallogenic belt of podiform Cr and related deposits formed during subduction-related intrusion of mafic-ultramafic plutons into the basal part of the Late Jurassic Koyukuk island arc (Nokleberg and others, 1993; Goldfarb, 1997; Nokleberg and others, 2000). Southwestern Alaska Metallogenic Belt of Zoned Mafic-Ultramafic PGE Deposits (Belt SWA), Southwestern Alaska The southwestern Alaska metallogenic belt of zoned mafic-ultramafic PGE deposits (fig. 49; tables 3, 4) are hosted in the Goodnews subduction-zone and Togiak island-arc terranes (Nokleberg and others, 1994c, 1997c). The significant deposits in the belt are (1) a concealed Fe-Ti (PGE) deposit at Kemuk, and (2) a zoned mafic-ultramafic PGE occurrence at Red Mountain (fig. 55) in ultramafic rocks at Goodnews Bay, which is interpreted as the source of the extensive placer PGE deposits in the region (table 4) (Southworth and Foley, 1986; Foley and others, 1997; Nokleberg and others 1997a,b, 1998). The ultramafic plutons that host the deposits in both areas are a part of a belt of similar zoned mafic to ultramafic Bering Sea Smalls River Red Mountain Salmon River Late Jurassic Metallogenic Belts (163 to 144 Ma; figs. 48, 49) 125 plutons that intrude both the Goodnews oceanic terrane and the adjacent Togiak island-arc terrane (Nokleberg and others, 1994c, 1997c). Kemuk Mountain Fe-Ti (PGE) Deposit The Kemuk Mountain Fe-Ti (PGE) deposit (Humble Oil and Refining Company, written commun., 1958; Eberlein and others, 1977; C.C. Hawley, written commun., 1980; Foley and others, 1997) consists of a buried titaniferous magnetite deposit in crudely zoned pyroxenite that is interpreted as part of a zoned Alaskan-type ultramafic pluton. A steeply dipping , high-temperature, contact metamorphic zone occurs in adjacent Permian quartzite and limestone. An aeromagnetic survey indicates the concealed pluton is about 1,500 m thick, and underlies about 6 km2 area. Based on Humble Oil and Refining Company drill data (written commun., 1988; Bundtzen and others, 1994), the deposit is estimated to contain 2,200 million tonnes grading 15 to 17 percent Fe, and 2 to 3 percent TiO2. Origin of and Tectonic Controls for Southwestern Alaska Metallogenic Belt The ultramafic plutons that host the Kemuk Mountain and Red Mountain deposits are a part of a belt of similar zoned mafic to ultramafic plutons that intrude both the Goodnews oceanic terrane and the adjacent Togiak island-arc terrane. These plutonic rocks are interpreted as the oldest known remnants of the Togiak island arc that consists chiefly of two major sequences (Box, Susie Mountain Alluvium and colluvium (Quaternary) Hornblende gabbro and hornblendite Clinopyroxenite Hornblende clinopyroxenite Dunite Wehrlite Sedimentary rock (Paleozoic and Mesozoic) Contact 0 2 km Figure 55. Red Mountain mafic-ultramafic PGE occurrence, southwestern Alaska metallogenic belt, southwestern Alaska. Occurrence is hosted in Goodnews Bay mafic-ultramafic complex. Schematic geologic map. Adapted from Southworth (1986) and Foley and others (1997). See figure 49 and table 4 for location. Jurassic
Page 1 and 2:
USGS Prepared in collaboration with
Page 3 and 4:
U.S. Department of the Interior Gal
Page 5 and 6:
iv Hart River SEDEX Zn-Cu-Ag Deposi
Page 7 and 8:
vi Specific Events for Middle Throu
Page 9 and 10:
viii Metallogenic Belts Formed Duri
Page 11 and 12:
x Origin of and Tectonic Controls f
Page 13 and 14:
xii Toodoggone Metallogenic Belt of
Page 15 and 16:
xiv Slate Creek Serpentinite-Hosted
Page 17 and 18:
xvi Left Omolon Belt of Porphyry Mo
Page 19 and 20:
xviii Origin of and Tectonic Contro
Page 21 and 22:
xx Chukotka Metallogenic Belt of Au
Page 23 and 24:
xxii Plutonic Rocks Hosting East-Ce
Page 25 and 26:
xxiv Skeena Metallogenic Belt of Po
Page 27 and 28:
xxvi Bee Creek Porphyry Cu Deposit
Page 29 and 30:
xxviii 36. Wellgreen gabbroic Ni-Cu
Page 31 and 32:
xxx 87. Partizanskoe Pb-Zn skarn de
Page 33 and 34:
Metallogenesis and Tectonics of the
Page 35 and 36:
format (Nokleberg and others, 1996)
Page 37 and 38:
logenesis of the region (1) subduct
Page 39 and 40:
Subterrane—A fault-bounded unit w
Page 41 and 42:
dilemma consists of two conflicting
Page 43 and 44:
2 to 20 m thick. A related dolomite
Page 45 and 46:
Lantarsky-Dzhugdzhur Metallogenic B
Page 47 and 48:
Origin of and Tectonic Controls for
Page 49 and 50:
Metallogenic Belts Formed During Pr
Page 51 and 52:
as at Oz, Monster, and Tart, may al
Page 53 and 54:
Monashee Metallogenic Belt of Sedim
Page 55 and 56:
Clark Range Metallogenic Belt of Se
Page 57 and 58:
in addition to the Fe deposits. Min
Page 59 and 60:
study) consists of lenses, from 100
Page 61 and 62:
Omulev Austrian Alps W Deposit The
Page 63 and 64:
ock, including coarse clastic rock,
Page 65 and 66:
lative metalliferous brines in a re
Page 67 and 68:
Prince of Wales Island Metallogenic
Page 69 and 70:
suite of deposits and host rocks ar
Page 71 and 72:
margin of the North American Craton
Page 73 and 74:
newly created terranes migrated int
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:
Page 85 and 86:
mentary rocks of the Cambrian to De
Page 87 and 88:
(Preto and Schiarizza, 1985; Schiar
Page 89 and 90:
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 97 and 98:
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 and 124: mental volcanic rocks of intermedia
Page 125 and 126: a resource of 34.3 million tonnes o
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
Page 145 and 146: to form along the leading edge of t
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: in a island arc that was tectonical
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 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
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:
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
Page 251 and 252:
(6) In the Paleocene (about 56 to 6
Page 253 and 254:
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
Page 267 and 268:
wim Group and altered mafic dikes.
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 and 306:
plates that exhibit magnetic anomal
Page 307 and 308:
stages (Petrenko, 1999): (1) In the
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
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
Page 373 and 374:
Table 2 Summary of correlations and
Page 375 and 376:
Table 2—Continued Unit(s) and Cor
Page 377 and 378:
Table 2—Continued Unit(s) and Cor
Page 379 and 380:
Table 3—Continued Metallogenic Be
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391 and 392:
Page 393 and 394:
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
Table 4. Significant lode deposits,
Page 401 and 402:
Table 4—Continued Appendix 369 De
Page 403 and 404:
Table 4—Continued Tracy Metalloge
Page 405 and 406:
Table 4—Continued Appendix 373 In
Page 407 and 408:
Table 4—Continued Deposit Name Mi
Page 409 and 410:
Table 4—Continued Mainits Metallo
Page 411 and 412:
Page 413 and 414:
Page 415 and 416:
Table 4—Continued Whitehorse Meta
Page 417 and 418:
Page 419 and 420:
Page 421 and 422:
Table 4—Continued Appendix 389 LA
Page 423 and 424:
Page 425 and 426:
Table 4—Continued Surprise Lake M
Page 427 and 428:
Table 4—Continued Sredinny Metall
Page 429:
show all

USGS Professional Paper 1697 - Alaska Resources Library

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?