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Bernard Mountain Prospect

Prospect in Alaska, United States with commodities Chromium, Nickel, Platinum
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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. Host and associated rocks
  9. Nearby scientific data
  10. Geologic structures
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Links to other databases
  16. Bibliographic references
  17. General comments
  18. Reporter information

Geologic information

Identification information

Deposit ID 10000839
MRDS ID A011492
Record type Site
Current site name Bernard Mountain Prospect
Alternate or previous names Red Mountain
Related records 10258792

Geographic coordinates

Geographic coordinates: -145.14423, 61.57796 (WGS84)
Location accuracy 2000(meters)
Relative position N SLOPE OF BERNARD MOUNTAIN

Site location context

Political divisions (FIPS codes)

Valdez-Cordova(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Valdez C-4(quadrangle 1:63,360 scale)

Valdez NE(quadrangle 1:100,000 scale)

Valdez C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Middle Copper River(hydrologic unit)

Copper River(hydrologic accounting unit)

South Central Alaska(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Comments on the location information

  • LOCATION APPROXIMATED FROM USGS OFR 80-892B, LOC. 42

Commodities

Commodity Importance
Chromium Critical Primary
Nickel Critical Tertiary
Platinum Critical Tertiary

Comments on the commodity information

  • ANOMALOUS IN PLATINUM GROUP ELEMENTS, NI AND CU

Materials information

Materials Type of material
Chromite Ore

Alteration

  • (Local) Serpentinization Widespread In Ultramafices

Analytical data

Result RANGE: 1500 PPM TO MORE THAN 5000 PPM CR, 1500 PPM TO 5000 PPM NI, MEAN: 5000 PPM CR, 2000 PPM NI, MAXIMUM PT CONCENTRATION .200 PPM, AVERAGE PT CONCENTRATION .023 PPM, HOFFMANN, BARRY, 1974, UNIV. OF ALASKA M. S. THESIS, P. 46, 50
Result TABLE CONCENTRATES FROM COMPOSITE OF CUT SAMPLES CONTAINED 48% CHROMITE WITH CR: FE RATIO OF 2.7, USBM IC 8626, P. 18

Host and associated rocks

  • Host or associated Associated
    Rock type Metamorphic Rock > Gneiss
    Rock unit name Streina Formation;Streina Formation;Streina Formation;Streina Formation;Streina Formation;Streina Formation;;;
    Rock description Streina Formation;Streina Formation;Streina Formation;Streina Formation;Streina Formation;Streina Formation;;;
  • Host or associated Host
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Hornblendite
    Rock unit name Bernard Mountain Ultramafic Body;Bernard Mountain Ultramafic Body;Bernard Mountain Ultramafic Body;Bernard Mountain Ultramafic Body
    Rock description Bernard Mountain Ultramafic Body;Bernard Mountain Ultramafic Body;Bernard Mountain Ultramafic Body;Bernard Mountain Ultramafic Body

Nearby scientific data

(1) -145.14423, 61.57796
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Area Cut By Three Major Faults; Bernard Mt. Fault, Kimball Pass Fault And One Cross Fault

Ore body information

  • General form LENSE
    Thickness 0.15M

Controls for ore emplacement

  • Mineralization Restricted To Ultramafics; Lithologic Control

Comments on the geologic information

  • BERNARD MT. IS PART OF A SERPENTINIZED DUNITE SILL THAT EXTENDS DISCONTINUOUSLY OVER 12 MI BY 1.5 MI AREA THAT ROUGHLY PARALLES THE TRACE OF THE BERNARD MT. FAULT; DUNITE AND ASSOCIATED ULTRAMAFICS IN BERNARD MT. AREA ARE INTRUDED INTO ROCKS CORRELATIVE WITH STRELNA FORMATION; N OF BERNARD MT. ULTRAMAFIC BODY STRELNA FORMATION ROCKS ARE INTRUDED BY TWO SMALL BODIES OF AMPHIBOLITE AND GRANULITE GNEISS CUT BY APLITE DIKES; ROCKS OF STRELNA ARE METAMORPHOSED TO LOW GREENSCHIST FACIES. STREINA FM (MISS-PERM) IS SLATE AND PHYLLITE WITH MINOR GRAYWACKE, GREENSTONE, ARKOSIC SANDSTONE, MARBLE.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic
Deposit size Small
Significant No

Mining district

District name Tonsina

Comments on development

  • USGS BEGAN INVESTIGATING AREA IN EARLY 1930'S; MOST OF BERNARD MT.AREA STAKED FOR CHROMITE BY EARLY 1960'S; GEOLOGICAL, GEOCHEMICAL AND GEOPHYSICAL EXPLORATION MOSTLY AFTER 1960; ALSO SOME TRENCHING, STRIPPING AND SYSTEMATIC SAMPLING; CLAIMS RESTAKED IN 1966; 81 UNPATENTED CLAIMS HELD IN EARLY 70'S

Reference information

Bibliographic references

  • Deposit

    USGS BULL 1246, P. 49, 52

  • Deposit

    ADGGS GC 15, P. 2, 4

  • Deposit

    USBM IC 8626, P. 18

  • Deposit

    HOFFMANN, BARRY, 1974, GEOLOGY OF THE BERNARD MOUNTAIN AREA, TONSINA, ALASKA: COLLEGE, ALASKA, UNIVERSITY OF ALASKA M. S. THESIS, 68 P.

  • Deposit

    USGS OFR 78-1-E, P. 19

  • Deposit

    USGS MF-438, LOC. 51

  • Deposit

    USGS OFR 80-892B, LOC. 42

  • Other Database

    BAG-OFR-80-892B-42

General comments

Subject category Comment text
Deposit LAYERS, LENSES AND DISSEMINATIONS OF CHROMITE IN DUNITE AND ASSOCIATED ULTRAMAFICS; CHROMITE OCCURS AS DISSEMINATED GRAINS THAT FORM 0.5 TO 1% OF DUNITE, OR AS CONCENTRATIONS OF FROM 2 TO 40% CHROMITE IN TRAINS SEVERAL GRAINS WIDE, MASSIVE LENSES, OR LAYERS UP TO 6 IN THICK
Deposit DESPITE PROXIMITY TO RICHARDSON HIGHWAY, SUFFICIENT QUANTITIES OF ORE GRADE CHROMITE HAVE NOT BEEN PROVEN AND AREA REMAINS UNECONOMIC; MIGHT BE MINED UNDER VERY UNUSUAL ECONOMIC CONDITIONS; SEE ALSO: DUST MOUNTAIN, SHEEP MOUNTAIN ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUL-1985 Leonard, Kenneth R. (Elliott, R. L.) U.S. Geological Survey PARSED DATA INTO WORKINGS AND ORE BODY MULTIVALUED FIELDS
Editor 14-APR-1994 Mosier, Dan U.S. Geological Survey
Editor 30-MAY-1995 Waller, Nichelle (Mosier, Dan) U.S. Geological Survey

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.