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

Carita

Prospect in Alaska, United States with commodities Copper, Barium-Barite
Map
XML
JSON
KML
B
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 10001605
MRDS ID A012368
Record type Site
Current site name Carita
Alternate or previous names Erhart, Starlight
Related records 10282971

Geographic coordinates

Geographic coordinates: -131.78288, 55.16668 (WGS84)
Relative position The Carita group of prospects is in section 25, T. 77 S., R. 90 E., of the Copper River Meridian, at or near the east corner of Nehenta Bay. The prospects are in an estimated half-mile-square area that trends roughly eastward from the shoreline of the bay to an elevation of about 200 feet. The map site is at the approximate center of the group of prospects and is accurate within a few hundred feet. The site corresponds to loc. 124 in Elliott and others (1978), and to loc. 316 (1-5) in Maas and others (1995).? Also see Additional comments.

Site location context

Political divisions (FIPS codes)

Ketchikan Gateway(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ketchikan A-6(quadrangle 1:63,360 scale)

Ketchikan SW(quadrangle 1:100,000 scale)

Ketchikan(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Ketchikan(hydrologic unit)

Southern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Tongass National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Barium-Barite Critical Secondary

Materials information

Materials Type of material
Barite Ore
Chalcopyrite Ore
Galena Ore
Pyrite Ore
Sphalerite Ore
Quartz Gangue
Siderite Gangue

Alteration

  • (Local) Locally conspicuous iron staining. Probably local silicification, carbonatization, pyritization, and introduction of hydrothermal hematite.

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

Nearby scientific data

(1) -131.78288, 55.16668
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Southern Gravina Island is underlain by an assemblage of undivided Silurian or Ordovician metamorphosed bedded and intrusive rocks; a stock and associated dikes of Silurian trondhjemite that cuts the metamorphic assemblage; and a sequence of Upper Triassic carbonate, clastic, rhyolitic, and basaltic strata that unconformably overlies the older rocks (Berg, 1973, 1982; Berg and others, 1988). In many places, the Triassic rhyolite and the rocks beneath it are permeated by microscopic particles of hydrothermal hematite, giving them a pink, purple, or red hue (Berg, 1973, p. 14). The country rocks in the area of the Carita prospects are cut by a complex system of high-angle faults that strike NE and NW, and by at least one thrust fault that dips gently northward (Berg, 1973, pl. 1).? Brooks (1902, p. 73) described the Erhart and Starlight claims. The Erhart prospect is a mineralized shear zone in porphyritic rock. The mineralization, chiefly chalcopyrite, extends over a width of 4-5 feet, but the richer parts are less than 2 feet thick. On the Starlight claim, the deposit is a quartz-chalcopyrite-pyrite breccia zone about 3 feet thick, apparently hosted by the same country rocks as the deposit at the Erhart prospect.?Wright and Wright (1908, p. 140) describe the Carita deposit only as a chalcopyrite-bearing quartz vein in calcic conglomerate.? Maas and others (1995, p. 227) report that exploration of the Carita group by private interests in 1973-74 identified a zone of mineralized, siliceous breccia hosted by limestone, metavolcanic rocks (greenschist), and altered trondhjemite. The breccia includes quartz, barite, siderite, pyrite, galena, sphalerite, and chalcopyrite. The zone was defined by geochemical anomalies in soil samples, and by an induced polarization survey. Four holes, totalling about 200 feet, drilled to test the anomaly, indicated only minor copper mineralization. The richest 10-foot section assayed 0.28% Cu. Maas and others (1995, p. 229) were able to locate a 50-foot adit and a few small pits and trenches, but not the other adit and shafts reported in the area.? the characteristics and setting of the Carita deposits indicate that they are polymetallic veins of Late Triassic or younger age.
  • Age = Late Triassic or younger.

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 = Development work in the early 1900s included an opencut and a 50-foot tunnel (Brooks, 1902, p. 73). Maas and others (1995, p. 227) report that exploration of the Carita group by private interests in 1973-74 identified a zone of mineralized, siliceous breccia hosted by limestone, metavolcanic rocks (greenschist), and altered trondhjemite. The breccia includes quartz, barite, siderite, pyrite, galena, sphalerite, and chalcopyrite. The zone was defined by geochemical anomalies in soil samples, and by an induced polarization survey. Four holes, totalling about 200 feet, drilled to test the anomaly, indicated only minor copper mineralization. The richest 10-foot section assayed 0.28% Cu. Maas and others (1995, p. 229) were able to locate a 50-foot adit and a few small pits and trenches, but not the other adit and shafts reported in the area.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Brooks, 1902; Maas and others, 1995

General comments

Subject category Comment text
Deposit Model Name = Polymetallic veins (Cox and Singer, 1986; model 22c)
Deposit Other Comments = Early descriptions of the Carita group of prospects also refer to the Erhart and Starlight claims (Cobb and Elliott, 1980, p. 24).

Reporter information

Type Date Name Affiliation Comment
Reporter 05-JUL-1999 H.C. Berg 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.