Derwent

Occurrence in Alaska, United States with commodities Zinc, Silver, Molybdenum, Uranium, Vanadium

Geologic information

Identification information

Deposit ID 10307399
Record type Site
Current site name Derwent

Geographic coordinates

Geographic coordinates: -142.30279, 65.04977 (WGS84)
Relative position The Derwent zone covers a large area along an east-northeast trend from section 11 in the northeast corner of T. 2 N., R. 26 E., of the Fairbanks Meridian to section 22, just southeast of the center of T. 3 N., R. 27 E., of the Fairbanks Meridian. The coordinates are for the approximate center of the zone, in section 32, T. 3 N., R. 27 N., of the Fairbanks Meridian. This prospect is located on Doyon, Limited selected or conveyed land. The location is accurate to within 1 or 2 miles.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Zinc Primary
Silver Secondary
Molybdenum Secondary
Uranium Secondary
Vanadium Secondary

Materials information

Materials Type of material
Azurite Ore
Chalcopyrite Ore
Malachite Ore
Sphalerite Ore

Mineral occurrence model information

Model code 208
USGS model code 31a
BC deposit profile E14
Deposit model name Sedimentary exhalative Zn-Pb
Mark3 model number 13

Nearby scientific data

(1) -142.30279, 65.04977

Comments on the geologic information

  • Geologic Description = The Derwent zone of zinc geochemical anomalies is hosted by a northwest-trending belt of metasedimentary and possibly metavolcanic rocks. This belt lies between a granitic batholith and the Tintina fault (Doyon, Limited, 1998). The zone extends for 24 miles between the Seventymile and Charley Rivers. It is mostly underlain by Paleozoic phyllite, graphitic schist, chert, phyllite, and marble (Doyon, Limited, 1998). . The zone has been defined by soil samples containing zinc values greater than 5,200 ppm zinc. Some samples, especially ones from a color anomaly, are also weakly anomalous in copper, silver, molybdenum, vanadium, tungsten, and uranium. Soils contain greater than 5,200 parts per million Zn, 3.4 parts per million Ag, 3,000 parts per million V, 18 parts per million U, and 285 parts per million Mo. All of the soil anomalies are probably due to elevated background concentrations in the metasedimentary rocks. Locally, the zone contains quartz veins and segregations that carry visible copper sulfides and oxides. Also, samples of graphitic schist breccia contain 920 parts per million Zn, 900 parts per million V, 85 parts per million Mo, 7 parts per million U, and 1.2 parts per million Ag (Doyon, Limited, 1986). The Derwent zone may be a fault-offset block from near the Anvil district that has been displaced 300 miles by the Tintina fault (Doyon, Limited, 1998). This area has been examined by stream silt samples, panned concentrates, soil and rock sampling of the color anomalies, and regional reconnaissance since the mid-1970s (Doyon, Limited, 1998).
  • Age = Paleozoic

Economic information

Economic information about the deposit and operations

Development status Occurrence

Comments on exploration

  • Status = Active

Mining district

District name Eagle

Comments on the workings information

  • Workings / Exploration = Since the mid-1970s, this area has been examined by stream silt samples, panned concentrates, soil and rock sampling of the color anomalies, and regional geologic reconnaissance (Doyon, Limited, 1998).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF CY008

Bibliographic references

  • Deposit

    Doyon, Limited, 1986, Mines, prospects, and geochemical anomalies on Doyon, Limited, regional overselection lands, Alaska: Fairbanks, Alaska, Doyon, Limited, Report 86-01A, v. 1, 150 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

  • Deposit

    Schmidt, J.M., 1997, Shale-hosted Zn-Pb-Ag and barite deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska, 1997: Economic Geology Monograph 9, p. 35-65.

  • Deposit

    Doyon, Limited, 1998, Veta Prospects 1997 Volume 1: Fairbanks, Alaska, Doyon, Limited., unpublished report 98-10, 256 p. (Report held by Doyon, Limited, Fairbanks, Alaska.)

Comments on the references

  • Primary Reference = Doyon, Limited, 1998

General comments

Subject category Comment text
Deposit Model Name = Shale-hosted Zn-Pb (Schmidt, 1997; Cox and Singer, 1986; model 31a).
Deposit Other Comments = These prospects are located on Doyon, Limited selected or conveyed land. For more information, contact Doyon, Limited.

Reporter information

Type Date Name Affiliation Comment
Reporter 07-APR-00 Cameron, C.E. Alaska Division of Geological and Geophysical Surveys