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Bear Mountain occurrence, Sheenjek Mining District, Yukon-Koyukuk Census Area, Alaska, USAi
Regional Level Types
Bear Mountain occurrenceOccurrence
Sheenjek Mining DistrictMining District
Yukon-Koyukuk Census AreaCensus Area
AlaskaState
USACountry

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Latitude & Longitude (WGS84):
68° 22' 12'' North , 142° 9' 0'' West
Latitude & Longitude (decimal):
68.37000,-142.15000
GeoHash:
G#: bu4uvq3s0
GRN:
N46W41
Type:
Occurrence
Köppen climate type:
ET : Tundra
Mindat Locality ID:
196416
Long-form identifier:
mindat:1:2:196416:8
GUID (UUID V4):
0


Part of regional E-W trend of small domes, intrusions and doubly-plunging anticlines.

Location: Location is approximate center of area 1.25 mi (2 km) (east-west) by 0.35 mi (0.55 km )(north-south) of anomalous samples 517-521 and 608-13 of Barker (1981, pl. A-3); about 4 mi (6.4 km) southwest of Bear Mountain summit; known to within 2000 ft (610 m).

Geology: Tungsten-rich porphyry molybdenum occurrence. Area of about 1 sq km underlain by altered complex of rhyolite porphyry, quartz porphyry, and a pipe-shaped core of intrusive breccia about 300 m in diameter; complex is cut by dikes of rhyolite porphyry and aplite. Mineralized area defined by Mo-rich gossan zone trending NW for 1.5 km over 40 ha area characterized by soil samples containing 600 ppm Mo or greater; nearly coincident with 30 ha area of soil samples containing 500 ppm W or greater. Total area of Mo + W mineralization about 50 ha; vertical and horizontal zonation evident. Central Mo-rich gossan zone, outer zone of wolframite-topaz mineralization in a Fe-enriched upper-level phase of the complex below a silicified cap, and peripheral zone of Pb-enrichment. Sulfides have largely been oxidized to limonite, hematite, goethite, jarosite, and secondary ferromolybdates; wolframite occurs as disseminated grains in porphyritic rock, quartz veins, and silicified gossan. Molybdenite and galena have each been noted in only one locality. Tertiary rhyolite porphyry stock intrudes Mississippian and older metasedimentary rocks (Barker, 1981, p. 33-40, 106-137).

Workings: Rock samples taken in 1983 contain 0.1-0.8% M, 0.06-0.6% W, 2.2% F, 60-120 PPM Nb as reported in Barker and Swainbank (1985); soil sample 2521 on p. 141 of Barker (1981) from area of intrusive breccia contains 4900 ppm Mo, 860 ppm W, 400 ppm Pb and 9.7 ppm U (Barker, 1981, p. 140-150).

Alteration: Core of sericitic and argillic alteration with outer zone of silicification; local peripheral areas of pyritic and propylitic alteration.

Commodities (Major) - Mo, W, Pb

Development Status: No

Deposit Model: Lode; Mo-W porphyry breccia

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.


Mineral List


14 valid minerals.

Detailed Mineral List:

ⓘ 'Biotite'
Formula: K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
ⓘ Ferberite
Formula: FeWO4
ⓘ Galena
Formula: PbS
ⓘ 'Garnet Group'
Formula: X3Z2(SiO4)3
ⓘ Goethite
Formula: Fe3+O(OH)
ⓘ Hematite
Formula: Fe2O3
ⓘ Hübnerite
Formula: MnWO4
ⓘ Jarosite
Formula: KFe3+3(SO4)2(OH)6
ⓘ Kaolinite
Formula: Al2(Si2O5)(OH)4
ⓘ 'K Feldspar'
ⓘ 'Limonite'
ⓘ Magnetite
Formula: Fe2+Fe3+2O4
ⓘ Molybdenite
Formula: MoS2
ⓘ Muscovite
Formula: KAl2(AlSi3O10)(OH)2
ⓘ Muscovite var. Sericite
Formula: KAl2(AlSi3O10)(OH)2
ⓘ Pyrite
Formula: FeS2
ⓘ Quartz
Formula: SiO2
ⓘ Quartz var. Smoky Quartz
Formula: SiO2
ⓘ Rutile
Formula: TiO2
ⓘ Topaz
Formula: Al2(SiO4)(F,OH)2
ⓘ 'Wolframite Group'

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
ⓘGalena2.CD.10PbS
ⓘMolybdenite2.EA.30MoS2
ⓘPyrite2.EB.05aFeS2
Group 4 - Oxides and Hydroxides
ⓘGoethite4.00.Fe3+O(OH)
ⓘMagnetite4.BB.05Fe2+Fe3+2O4
ⓘHematite4.CB.05Fe2O3
ⓘQuartz4.DA.05SiO2
ⓘvar. Smoky Quartz4.DA.05SiO2
ⓘRutile4.DB.05TiO2
ⓘFerberite4.DB.30FeWO4
ⓘHübnerite4.DB.30MnWO4
ⓘ'Wolframite Group'4.DB.30 va
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
ⓘJarosite7.BC.10KFe3+3(SO4)2(OH)6
Group 9 - Silicates
ⓘTopaz9.AF.35Al2(SiO4)(F,OH)2
ⓘMuscovite9.EC.15KAl2(AlSi3O10)(OH)2
ⓘvar. Sericite9.EC.15KAl2(AlSi3O10)(OH)2
ⓘKaolinite9.ED.05Al2(Si2O5)(OH)4
Unclassified
ⓘ'Biotite'-K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
ⓘ'Limonite'-
ⓘ'K Feldspar'-
ⓘ'Garnet Group'-X3Z2(SiO4)3

List of minerals for each chemical element

HHydrogen
Hⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Hⓘ GoethiteFe3+O(OH)
Hⓘ JarositeKFe33+(SO4)2(OH)6
Hⓘ KaoliniteAl2(Si2O5)(OH)4
Hⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Hⓘ TopazAl2(SiO4)(F,OH)2
Hⓘ Muscovite var. SericiteKAl2(AlSi3O10)(OH)2
OOxygen
Oⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Oⓘ FerberiteFeWO4
Oⓘ GoethiteFe3+O(OH)
Oⓘ HematiteFe2O3
Oⓘ HübneriteMnWO4
Oⓘ JarositeKFe33+(SO4)2(OH)6
Oⓘ KaoliniteAl2(Si2O5)(OH)4
Oⓘ MagnetiteFe2+Fe23+O4
Oⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Oⓘ QuartzSiO2
Oⓘ RutileTiO2
Oⓘ Quartz var. Smoky QuartzSiO2
Oⓘ TopazAl2(SiO4)(F,OH)2
Oⓘ Muscovite var. SericiteKAl2(AlSi3O10)(OH)2
Oⓘ Garnet GroupX3Z2(SiO4)3
FFluorine
Fⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Fⓘ TopazAl2(SiO4)(F,OH)2
MgMagnesium
Mgⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
AlAluminium
Alⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Alⓘ KaoliniteAl2(Si2O5)(OH)4
Alⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Alⓘ TopazAl2(SiO4)(F,OH)2
Alⓘ Muscovite var. SericiteKAl2(AlSi3O10)(OH)2
SiSilicon
Siⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Siⓘ KaoliniteAl2(Si2O5)(OH)4
Siⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Siⓘ QuartzSiO2
Siⓘ Quartz var. Smoky QuartzSiO2
Siⓘ TopazAl2(SiO4)(F,OH)2
Siⓘ Muscovite var. SericiteKAl2(AlSi3O10)(OH)2
Siⓘ Garnet GroupX3Z2(SiO4)3
SSulfur
Sⓘ GalenaPbS
Sⓘ JarositeKFe33+(SO4)2(OH)6
Sⓘ MolybdeniteMoS2
Sⓘ PyriteFeS2
KPotassium
Kⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Kⓘ JarositeKFe33+(SO4)2(OH)6
Kⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Kⓘ Muscovite var. SericiteKAl2(AlSi3O10)(OH)2
TiTitanium
Tiⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Tiⓘ RutileTiO2
MnManganese
Mnⓘ HübneriteMnWO4
FeIron
Feⓘ BiotiteK(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Feⓘ FerberiteFeWO4
Feⓘ GoethiteFe3+O(OH)
Feⓘ HematiteFe2O3
Feⓘ JarositeKFe33+(SO4)2(OH)6
Feⓘ MagnetiteFe2+Fe23+O4
Feⓘ PyriteFeS2
MoMolybdenum
Moⓘ MolybdeniteMoS2
WTungsten
Wⓘ FerberiteFeWO4
Wⓘ HübneriteMnWO4
PbLead
Pbⓘ GalenaPbS

Other Databases

Link to USGS - Alaska:TB004
Link to USGS MRDS:10001758
Link to USGS MRDS:10257765

Other Regions, Features and Areas containing this locality

North AmericaContinent
North America PlateTectonic Plate

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

USGS MRDS ID #A012545.
Brosge, W.P., and Reiser, H.N. (1968), Geochemical maps of granitic rocks, Coleen and Table Mountain quadrangles, Alaska: USGS Open-File Report 323, scale 1:250,000.
Cobb, E.H. (1973), Placer deposits of Alaska: USGS Bulletin 1374, 213 pages.
Brosge, W.P., Reiser, H.N. (1976), Preliminary geologic and mineral resource maps (excluding petroleum), Arctic National Wildlife Range, Alaska: USGS Open-File Report 76-539, 4 sheets, scale 1:500,000.
Grybeck, D.J. (1977), Known mineral deposits of the Brooks Range, Alaska: USGS Open-File Report 77-166C, 41 pages, 1 sheet, scale 1:1,000,000.
Barker, J.C. (1978), Mineral Investigations of certain lands in the eastern Brooks Range: a summary report: U.S. Bureau of Mines Open-File No. 63-78, 25 pages, 5 sheets.
Barker, J.C. (1981), Mineral investigations of certain lands in the eastern Brooks Range, 1978: U.S. Bureau of Mines Open-File 37-81, 288 pages, 8 sheets.
Cobb, E.H., Mayfield, C.F., and Brosge, W.P. (1981), Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in eleven quadrangles in northern Alaska (Arctic, Baird Mountains, Chandler Lake, DeLong Mountains, Demarcation Point, Howard Pass, Misheguk Mountain, Mount Michelson, Noatak, Point Lay, and Table Mountain); Supplement to Open-File Report 75-628; Part A, Summaries of data to January 1, 1981: USGS Open-File Report 81-767-A, 25 pages.
Barker, J.C., and Swainbank, R.C. (1985), A tungsten-rich porphyry molybdenum occurrence at Bear Mountain, northeast Alaska: U.S. Bureau of Mines Open-File Report 8-85, 64 pages.
Barker, J.C., and Swainbank, R.C. (1986), A tungsten-rich porphyry molybdenum occurrence at Bear Mountain, northeast Alaska: Economic Geology: 81: 1753-1759.
U.S. Bureau of Mines (1995), Minerals Availability System/Mineral Industry Location System (MAS/MILS), U.S. Bureau of Mines, file ID #0020250002.
(2005) Mineral Resources Data System (MRDS), US Geological Survey.
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