1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Unnamed (ridge NE of Round Mountain)

Occurrence in Alaska, United States with commodity Copper
Map
XML
JSON
KML
C

Geologic information

Identification information

Deposit ID 10001610
MRDS ID A012374
Record type Site
Current site name Unnamed (ridge NE of Round Mountain)

Geographic coordinates

Geographic coordinates: -131.54482, 55.21168 (WGS84)
Relative position This site includes 4 occurrences in about a half-mile-square area northeast of Round Mountain. The occurrences are in sections 3, 9, and 10, T. 77 S., R. 92 E., of the Copper River Meridian, and are at elevations of 1200-1500 feet on and near the northeast spur of Round Mountain, and about a mile northeast of the top of the mountain. The map site is at the approximate center of the area of occurrences. The site corresponds to loc. 21 in Berg (1972 [I 684]), loc. 132 in Elliott and others (1978), and loc. 11a-d in Karl (1992). The location is accurate within about 0.1 mile.
(click for info)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary

Materials information

Materials Type of material
Malachite Ore
Pyrite Ore
Calcite Gangue
Quartz Gangue

Alteration

  • (Local) Local bleaching and iron and copper staining.

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Conglomerate
    Stratigraphic age (youngest) Late Permian

Nearby scientific data

(1) -131.54482, 55.21168
ListMap

Comments on the geologic information

  • Geologic Description = The hostrocks of these occurrences are bounded by faults, and consist of recrystallized, Upper Triassic sedimentary and volcanic rocks that unconformably overlie a sequence of undivided, metamorphosed Silurian and Ordovician volcanic, sedimentary, and intrusive rocks (Berg, 1972). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. ? the occurrences are in bleached, Upper Triassic, rhyolite tuff-breccia, black shale and limestone, and conglomerate. They consist of quartz-calcite-pyrite fissure veins in shear zones; of minute cubes of pyrite disseminated in the country rocks; and of local copper-staining (malachite) (Berg, 1972; Karl, 1992). A sample of felsic tuff-breccia contained 150 ppm Pb; a sample of a quartz-calcite-pyrite fissure vein contained 300 ppm Cu; and a sample of sheared rhyolite breccia contained 700 ppm Pb (Karl, 1992, loc. 11a-d).
  • Age = The fissure veins probably are Late Cretaceous or younger in age.

Economic information

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Mining district

District name Ketchikan

Comments on the workings information

  • Workings / Exploration = A sample of felsic tuff-breccia contained 150 ppm Pb; a sample of a quartz-calcite-pyrite fissure vein contained 300 ppm Cu; and a sample of sheared rhyolite breccia contained 700 ppm Pb (Karl, 1992, loc. 11a-d).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012374
USGS Alaska Resource Data File ARDF KC135

Bibliographic references

  • Deposit

    Berg, H.C., 1972, Geologic map of Annette Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-684, 8 p., 1 sheet, scale 1:63,360,

  • 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

    Karl, S.M., 1992, Map and table of mineral deposits on Annette Island, Alaska: U.S. Geological Survey Open-File Report 92-690, 57 p., 1 map, scale 1:63,360.

Comments on the references

  • Primary Reference = Karl, 1992

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins? (Cox and Singer, 1986; model 22c)

Reporter information

Type Date Name Affiliation Comment
Reporter 06-JUL-1999 H.C. Berg U.S. Geological Survey