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Sischu Mountain

Prospect in Alaska, United States with commodities Tin, Arsenic, Gold, Bismuth, Copper, Manganese, Molybdenum, Nickel, Antimony, Zinc, Zirconium
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Nearby scientific data
  9. Economic information about the deposit and operations
  10. Mining district
  11. Links to other databases
  12. Bibliographic references
  13. General comments
  14. Reporter information

Geologic information

Identification information

Deposit ID 10307708
Record type Site
Current site name Sischu Mountain

Geographic coordinates

Geographic coordinates: -152.926, 64.10354 (WGS84)
Relative position The Sischu Mountain prospects cover about 20 square miles, including Sischu Mountain and several surrounding peaks. The approximate center of the prospect area is in NE1/4SW1/4 section 30, T. 9 S., R. 27 W., of the Fairbanks Meridian. There is an airstrip at Lake Minchumina approximately 30 miles southeast of the prospects. The Sischu Mountain prospects are located on land selected by or conveyed to Doyon, Limited.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Kantishna River A-6(quadrangle 1:63,360 scale)

Kantishna River SW(quadrangle 1:100,000 scale)

Kantishna River(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Federal lands

BLM(Federal land areas administered by BLM)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Tin Critical Primary
Arsenic Critical Secondary
Gold Secondary
Bismuth Critical Secondary
Copper Secondary
Manganese Critical Secondary
Molybdenum Secondary
Nickel Critical Secondary
Antimony Critical Secondary
Zinc Critical Secondary
Zirconium Critical Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Magnetite Ore
Pyrite Ore
Chlorite Gangue
Goethite Gangue
Kaolinite Gangue
Quartz Gangue
Tourmaline Gangue

Alteration

  • (Local) On Sischu Mountain, float samples exhibit silicification and chlorite-kaolinite alteration and vein brecciation with tourmaline. An area identified by a color anomaly consists of hydrothermally brecciated sandstone fragments in a goethite matrix.

Nearby scientific data

(1) -152.926, 64.10354
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Sischu Mountain is composed of multiple igneous phases intruding phyllite, limestone, and siltstone to the north and various volcanic rocks, including rhyolite, dacite, andesite, and basalt, to the south and east (Chapman and Yeend, 1981). The phyllite, limestone, and siltstone are of Devonian age, and the intrusive rocks are Cretaceous to Tertiary (Chapman and Yeend, 1981). Float mapping has found aplite, coarse biotite granite, porphyry granite, hornblende-biotite monzodiorite, and porphyry dikes (Bond, 1985). Regionally, the area contains a system of northeast-trending strike-slip and related conjugate faults associated with Cretaceous to Tertiary plutonic rocks and coeval or younger volcanic rocks (Clautice and others, 1993). On Sischu Mountain, float samples exhibit silicification and chlorite-kaolinite alteration and vein brecciation with tourmaline. Disseminated pyrite and chalcopyrite occur in altered intrusive rock. Some aplite dikes contain as much as 1 percent magnetite. An area identified by a color anomaly consists of hydrothermally brecciated sandstone fragments in a goethite matrix. A rock chip of altered granite contained as much as 1,450 ppm As, 25 ppm Bi, 100 ppm Sn, and 15 ppm Mo (Bond, 1985). Clautice and others (1993) reported analyses of several samples: (1) a rhyolite dike cutting limestone contained as much as 1,200 ppm Zr, 86 ppm Cu, 542 ppm Zn, 265 ppm Ni, 136 ppm As, 35 ppm Sb, 799 ppm Mn, and 10 ppm Sn; (2) limestone near a granitic contact contained as much as 114 ppm As; (3) equigranular, biotite monzonite contained 767 ppm Zn, 47 ppm As, 23 ppm Pb, and 6 ppm Sn; (4) a rhyolite dike in limestone contained 132 ppm As, 590 ppm Mn, and 38 ppm Pb; and (5) limonitic rhyolite contained 105 ppm As and 463 ppm Mn. A regional stream sediment sampling, airborne radiometrics, and mapping program in 1975-76 and 1980 identified several anomalies. In 1984, one sample was collected. In 1985, exploration efforts consisted of mapping and collecting 12 rock chip, 7 stream sediments, and 8 pan concentrate samples (Bond, 1985). There are no indications of production.
  • Age = Probably related to Cretaceous to Tertiary plutonism.

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name Ruby

Comments on the production information

  • Production Notes = There are no indications of production.

Comments on the workings information

  • Workings / Exploration = A regional stream sediment sampling, airborne radiometrics, and mapping program in 1975-76 and 1980 identified several anomalies. In 1984, one sample was collected. In 1985, exploration efforts consisted of mapping and collecting 12 rock chip, 7 stream sediments, and 8 pan concentrate samples (Bond, 1985). There are no indications of production.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Bond, 1985

General comments

Subject category Comment text
Deposit Model Name = Plutonic-related mesothermal veining.
Deposit Other Comments = the Sischu Mountain prospects are located on land selected by or conveyed to Doyon, Limited. For more information, contact Doyon, Limited.

Reporter information

Type Date Name Affiliation Comment
Reporter 08-NOV-99 Cameron S. Rombach Alaska Division of Geological and Geophysical Surveys

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.