Little Rocky Creek Ni-Cu

Occurrence in Stillwater county in Montana, United States with commodities Nickel, Copper, Cobalt, PGE, Silver, Gold
Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Land status
  18. Ownership information
  19. Workings at the site
  20. Links to other databases
  21. Bibliographic references
  22. Reporter information

Geologic information

Identification information

Deposit ID 10042344
MRDS ID M060097
Record type Site
Current site name Little Rocky Creek Ni-Cu
Alternate or previous names Benbow, Rocky Group, Chrome Lake

Geographic coordinates

Geographic coordinates: -109.80551, 45.35714 (WGS84)
Elevation 2576
Location accuracy 100(meters)
Relative position ABOUT 0.5 MI NORTHWEST OF CHROME LAKE, Acc Generalized Location Of Adit Near Little Rocks Creek

Site location context

Political divisions (FIPS codes)

Stillwater(county)

Montana(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Mount Wood(quadrangle 1:24,000 scale)

Red Lodge(quadrangle 1:100,000 scale)

Billings(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Stillwater(hydrologic unit)

Upper Yellowstone(hydrologic accounting unit)

Upper Yellowstone(hydrologic subregion)

Missouri(hydrologic region)

Federal lands

Custer Gallatin National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Montana Stillwater

Public Land Survey System information

Meridian Township Range Section Fraction State
Montana Principal 005S 016E 31 Montana

Comments on the location information

  • UNSURVEYED. IN CUSTER NATIONAL FOREST

Commodities

Commodity Importance
Nickel Critical Primary
Copper Primary
Cobalt Critical Secondary
PGE Critical Tertiary
Silver Tertiary
Gold Tertiary

Comments on the commodity information

  • SEE PAGE (1979) FOR GENERAL DESCRIPTION OF BASAL SERIES MINERALIZATION.

Materials information

Materials Type of material
Chalcopyrite Ore
Pentlandite Ore
Pyrrhotite Ore
Magnetite Gangue
Plagioclase Gangue

Alteration

  • (Local) None Related To Ore-Forming Process

Analytical data

Result AVERAGE OF ANALYSES OF SURFACE SAMPLES: 32.8 PPB PT, 9.1 PPB PD (MAX. 190 PPB PT, 18 PPB PD)

Mineral occurrence model information

Model code 1
USGS model code 1
Deposit model name Stillwater Ni-Cu

Host and associated rocks

  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
    Stratigraphic age (youngest) Early Cretaceous
    Stratigraphic age (youngest) Neoarchean
  • Host or associated Host
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Peridotite
  • Host or associated Host
    Rock type Metamorphic Rock > Hornfels

Nearby scientific data

(1) -109.80551, 45.35714

Economic information

Geologic structures

Type of structure Regional
Structure description The Stillwater Complex Is Exposed Along The Northern Margin Of The Beartooth Uplift, One Of Several Laramide Basement-Cored Ranges That Make Up The Rocky Mountain Foreland Of South-Central Montana (Foose And Others, 1961: Kulik And Schmidt, 1988)
Type of structure Local
Structure description Local Faults Of Small Displacement

Ore body information

  • General form MASSIVE AND DISSEMINATED
    Depth to top 0M

Controls for ore emplacement

  • Immiscible Sulfide Liquid Enriched In Ni And Cu Exsolved From Mafic Silicate Magma And Accumulated Near Lower Contact Of The Stillwater Complex. Assimilation Of Sulfur From Rocks Adjacent To The Stillwater Complex May Have Led To The Exsolution Of The Sulfide Liquid (Zientek And Ripley, 1990)

Comments on the geologic information

  • AGE OF STILLWATER COMPLEX IS 2,705 +/- 4 MA BASED ON U-PB SYSTEMATICS ON ZIRCON-BADDELEYITE (PREMO AND OTHERS, 1990)

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1883
Discoverer Jack Nye, Jimmy And Jonas Hedges

Mining district

District name In Stillwater Complex

Land status

Ownership category National Forest

Ownership information

  • Type Operator
    Owner Amoco Minerals Co. (Operated Rocky Group)
    First year 1985

Workings at the site

  • Type of workings Underground
    Length 91.44M

Comments on the workings information

  • 4 ADITS, INACCESSIBLE; 9 DIAMOND DRILL HOLES TOTALING 5,564 FT DRILLED IN 1967-1970; 14 DRILLHOLES IN 1983 TOTALLING 20,073 FT

Reference information

Bibliographic references

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JAN-73 Dohrenwend, John C. U.S. Geological Survey
Updater 01-AUG-91 Peterson, Jocelyn A. U.S. Geological Survey

Beyond USGS

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