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Crash

Prospect in Alaska, United States with commodities Silver, Copper, Zinc, Gold, Lead
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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. Mineral occurrence model information
  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 10307858
Record type Site
Current site name Crash
Alternate or previous names Sheep Creek 2

Geographic coordinates

Geographic coordinates: -153.80184, 62.35248 (WGS84)
Relative position The Crash prospect is located in an unnamed east-flowing tributary of Sheep Creek, 4.0 kilometers northwest of Smith Lake; it is at an elevation of 2,800 feet (853 m) in the SW1/4 sec. 7, T. 26 N., R. 24 W., of the Seward Meridian. The Crash occurrence is 3.0 kilometers north of the Dahl Prospect (MG053). The reporter visited the site in 1981.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

McGrath B-2(quadrangle 1:63,360 scale)

McGrath SE(quadrangle 1:100,000 scale)

McGrath(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Cook Inlet Region, Incorporated(ANCSA Region)

ANCSA Region NTVPIC(Type of land area)

NTVPIC(Federal land areas administered by NTVPIC)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Copper Primary
Zinc Critical Primary
Gold Secondary
Lead Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Malachite Ore
Quartz Gangue

Mineral occurrence model information

Model code 208
USGS model code 31a
Deposit model name Sedimentary exhalative Zn-Pb
Mark3 model number 13
Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Nearby scientific data

(1) DSbr
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Crash prospect consists of two siliceous cataclastic breccias similar to those that host mineralization at the Dahl prospect (MG053). Exposed mineralization in one shale hosted breccia zone contains massive chalcopyrite, sphalerite, and traces of galena near the contact between the Lower Ordovician to Lower Silurian, Post River Formation and the mid- to Upper Silurian Terra Cotta Mountains Sandstone; both are units of the Dillinger subterrane (Bundtzen, Harris, and Gilbert, 1997). Another siliceous cataclastic breccia contains abundant arsenopyrite. Both sulfide bearing zones range from 3 to 30 centimeters thick, appear stratiform or parallel to sedimentary bedding, and are isoclinally folded, which suggests sulfides were formed prior to Lower Cretaceous compressive deformation (Bundtzen, Harris, and Gilbert, 1997). The mineralization at the Crash prospect might also be related to younger plutons. The larger massive sulfide-bearing breccia contained up to 16.5 percent copper and 926.8 grams/tonne silver (Brewer and others, 1992). The second cataclastic zone contains a 0.2 to 2.0 meter pod of massive arsenopyrite that contains 6.8 grams/tonne gold. Three samples collected by Smith and Albanese (1985) contain up to 316 ppm copper, 86 ppm lead, 940 ppm zinc, and 10.5 grams/tonne silver.
  • Age = Undated; inferred to be Lower Ordovician to Lower Silurian, based on graptolites found in mineralized area (Bundtzen, Harris, and Gilbert, 1997).

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name McGrath

Comments on the workings information

  • Workings / Exploration = Tom Smith and Mary Albanese first sampled the Sheep Creek-2 occurrence in 1982 during mineral investigations by the Alaska Division of Geological and Geophysical Surveys in the area (Smith and Albanese, 1985). One breccia zone with massive sulfide mineralization contained up to 16.5 percent copper and 926.8 grams/tonne silver. Another smaller siliceous breccia zone with massive arsenopyrite contained 6.5 grams/tonne gold (Brewer and others, 1992). Three random grab samples contained up to 316 ppm copper, 86 ppm lead, 940 ppm zinc, and 10.5 grams/tonne silver.

Reference information

Comments on the references

  • Primary Reference = This description

General comments

Subject category Comment text
Deposit Model Name = Uncertain; either sedimentary exhalitive lead-zinc (?) or polymetallic vein (Cox and Singer, 1986; model 31a or 22c).
Deposit Other Comments = the Crash prospect contains anomalous gold, which is atypical of most sulfide occurrences and prospects in the Farewell Mineral Belt. The Crash zone is in a splay structure associated with a regional fault that hosts the Dahl prospect (MG053).

Reporter information

Type Date Name Affiliation Comment
Reporter 07-DEC-98 T.K. Bundtzen Pacific Rim Geological Consulting

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.