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  3. Mineral Resource Data System (MRDS)

Bob

Occurrence in Alaska, United States with commodities Silver, Lead, Zinc
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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. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Economic information about the deposit and operations
  12. Mining district
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10001392
MRDS ID A012134
Record type Site
Current site name Bob

Geographic coordinates

Geographic coordinates: -148.68335, 67.87974 (WGS84)
Relative position This occurrence is at an elevation of about 4,500 feet on a ridge approximately 1 1/2 miles southwest of the headwater lake on Thru Creek (NE1/4 sec. 9, T. 35 N., R. 5 W., of the Fairbanks Meridian). The location is accurate within a 1/2-mile radius.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Chandalar D-4(quadrangle 1:63,360 scale)

Chandalar N(quadrangle 1:100,000 scale)

Chandalar C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Lead Primary
Zinc Critical Primary

Materials information

Materials Type of material
Galena Ore
Sphalerite Ore

Alteration

  • (Local) Calc-silicate.

Mineral occurrence model information

Model code 60
USGS model code 18c
Deposit model name Skarn Zn-Pb
Mark3 model number 22

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone

Nearby scientific data

(1) -148.68335, 67.87974
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Bob prospect is one of several Pb-Zn-Ag plus or minus Cu prospects near this site (DeYoung, 1978). Information specific to the property is sparse and only describes the prospect as galena and sphalerite with silver values in skarn associated with limestone (Grybeck, 1977). Newberry and others (1997) include the Bob prospect in a group of calcic Zn-Pb skarns and replacement bodies. These Zn-Pb skarns are described by Newberry and others (1986) as distal to Devonian(?) porphyry Cu-Mo systems associated with the Horace Mountain plutons in the Chandalar copper belt. The bedrock near of the prospect is mapped as Devonian Hunt Fork Shale near its contact with Skajit Limestone (Brosgi and Reiser, 1964). Intercalated diorite sills and andesitic flows(?) are also present in the section.
  • Age = Devonian based on reported Early Devonian Pb/Pb zircon ages from the associated Baby Creek batholith and Horace Mountain plutons (Dillon and others, 1996).

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Chandalar

Comments on the workings information

  • Workings / Exploration = Claims were located in 1972 and 1976 by Placid Oil. No other information is available.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Grybeck, 1977

General comments

Subject category Comment text
Deposit Model Name = Zn-Pb skarn deposits(?) (Cox and Singer, 1986; model 18c)
Deposit Other Comments = See also: Bibban prospect (CH090). Alaska Kardex No. 031-61A (Kardex is a card file mining claim information system located at the State of Alaska DNR Public Information Center in Fairbanks).

Reporter information

Type Date Name Affiliation Comment
Reporter 17-NOV-1999 J.M. Britton 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.