Typhoon

Prospect in Alaska, United States with commodity Gold

Geologic information

Identification information

Deposit ID 10001573
MRDS ID A012324
Record type Site
Current site name Typhoon
Related records 10258060

Geographic coordinates

Geographic coordinates: -131.80872, 55.41168 (WGS84)
Relative position The Typhoon prospect is at tidewater on the west side of the north end of Tongass Narrows, about 0.1 mile southwest of Rock Point. The site is in section 36, T. 74 S., R. 89 E., of the Copper River Meridian. It corresponds to loc. 55 in Elliott and others (1978) and to loc. 266 in Maas and others (1995). The location is accurate within 0.1 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary

Materials information

Materials Type of material
Gold Ore
Pyrite Ore
Quartz Gangue

Mineral occurrence model information

Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Slate

Nearby scientific data

(1) -131.80872, 55.41168

Comments on the geologic information

  • Geologic Description = The country rocks on northern Gravina Island are chiefly Upper Jurassic to mid-Cretaceous andesitic and basaltic volcanic rocks that gradationally intertongue with flyschlike sedimentary rocks. The rocks are intruded by at least one pluglike body of Tertiary gabbro (Berg, 1973; Berg and others, 1988). The bedded rocks were regionally metamorphosed to low-greenschist grade in Late Cretaceous time, and subsequently contact metamorphosed to hornblende hornfels near the contact of the Tertiary gabbro. The country rocks are cut by a high-angle fault along Tongass Narrows that displays about 4 miles of right-lateral offset.? the deposit is in Jurassic or Cretaceous slate and phyllite and consists of a reportedly auriferous, pyrite-bearing quartz fissure vein up to 8 inches thick (Brooks, 1902, p. 61). The vein strikes NE and dips steeply SE, at an angle to the N60W, 60NE foliation of the slate and phyllite.
  • Age = Late Cretaceous or younger.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Ketchikan

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012324
USGS Alaska Resource Data File ARDF KC058

Bibliographic references

  • Deposit

    Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.

  • Deposit

    Berg, H.C., 1973, Geology of Gravina Island Alaska: U.S. Geological Survey Bulletin 1373, 41 p.

  • Deposit

    Elliott, R.L., Berg, H.C., and Karl, Susan, 1978, map and table describing metalliferous and selected nonmetalliferous mineral deposits, Ketchikan and Prince Rupert quadrangles, Alaska: U.S. Geological Survey Open-file Report, 78-73-B,17 p., scale 1:250,000.

  • Deposit

    Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

Comments on the references

  • Primary Reference = Brooks, 1902; Berg, 1973

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1989; model 36a)

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUL-1999 H.C. Berg U.S. Geological Survey