Little Maumee

Prospect in Alaska, United States with commodities Gold, Copper

Geologic information

Identification information

Deposit ID 10001565
MRDS ID A012313
Record type Site
Current site name Little Maumee
Related records 10234063

Geographic coordinates

Geographic coordinates: -131.95373, 55.59863 (WGS84)
Relative position The approximate location of the Little Maumee prospect is at about 100 feet elevation, 0.1 mile inland from the southwest shore of Helm Bay, and 1.0 mile east -northeast of the head of the falls at the mouth of Falls Creek. The site is in section 29, T. 72 S., R. 88 E., of the Copper River Meridian. It corresponds to loc. 38 in Elliott and others (1978). The location is accurate within about 0.2 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Copper Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Gold Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Local pyritization of wallrock adjacent to principal vein.

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 Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite

Nearby scientific data

(1) -131.95373, 55.59863

Comments on the geologic information

  • Geologic Description = The country rocks near this site include gray and green phyllite and semischist derived from intertonguing flysch and andesitic and basaltic volcanic rocks (Berg and others, 1988, p. 17-20); and gray felsic schist possibly derived from silicic tuff (Maas and others, 1995, p. 183 and fig. 46). Near Smugglers Cove, the bedded rocks are intruded by diorite that may be transitional to the andesitic and basaltic volcanic rocks. The bedded and intrusive rocks were regionally metamorphosed to greenschist grade in Late Cretaceous time (Brew, 1996, p. 27). Their premetamorphic age is uncertain. Berg and others (1988, p. 17) note that the intertonguing flysch and volcanic rocks closely resemble Upper Jurassic to mid-Cretaceous marine strata nearby on Gravina Island.? the deposit consists of quartz fissure veins up to about 12 inches thick in porphyritic diorite (Brooks, 1902, p. 58). The principal vein strikes E-W and contains pyrite, chalcopyrite, and, reportedly, small amounts of gold. Small amounts of auriferous pyrite also are disseminated in the diorite adjacent to the vein. Fluid inclusion studies of quartz vein material from several of the Helm Bay lodes suggest that the veins formed at temperatures and pressures consistent with conditions during the Late Cretaceous greenschist-grade regional metamorphism (Maas and others, 1995, p. 184).
  • Age = Late Cretaceous.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = Workings in the early 1900s probably consisted of small pits and trenches.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012313
USGS Alaska Resource Data File ARDF KC038

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

    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.

  • Deposit

    Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.

  • Deposit

    Brew, D.A., 1996, Geologic map of the Craig, Dixon Entrance, and parts of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2319, 53 p., 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Brooks, 1902

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide gold-quartz veins (Cox and Singer, 1986; model 36a)

Reporter information

Type Date Name Affiliation Comment
Reporter 30-JUN-1999 H.C. Berg U.S. Geological Survey