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

Grenadier

Prospect in Alaska, United States with commodity Copper
Map
XML
JSON
KML
C
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. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10307666
Record type Site
Current site name Grenadier

Geographic coordinates

Geographic coordinates: -131.75077, 55.17274 (WGS84)
Relative position The approximate location of the Grenadier prospect is at an elevation of about 200 feet at the south foot of Punch Hill. The prospect is in section 19, T. 77 S., R. 91 E., of the Copper River Meridian. It is about 0.7 mile from Dall Bay, and is in, or adjacent to, the valley of an unnamed, southeast-flowing creek that reaches Dall Bay at its north entrance. The site corresponds to loc. 121 in Elliott and others (1978). The location probably is accurate within about 0.2 mile.

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

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) 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

Nearby scientific data

(1) CPxwg
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). The rocks are complexly folded and are cut by high-angle faults and by low-angle thrust faults. 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). Brooks (1902, p. 73) describes the Grenadier prospect as a mineralized shear or breccia zone at the contact of pegmatite with schist and greenstone. . Maas and others' (1995, p. 227) description of the mineral deposits in the area north of Dall Bay probably applies in general to the Grenadier deposit. They report that chalcopyrite is associated with sheared, silicified zones, chiefly in trondhjemite. Small barite veins are also found in the area. About 0.6 mile north of Dall Bay, chalcopyrite occurs as clasts or pods in a siderite-hematite matrix in altered trondhjemite. The Grenadier prospect is near the intersection of high-angle, NE- and NW-striking faults that juxtapose trondhjemite and metavolcanic rocks (Maas and others, 1995, fig. 58). The characteristics and setting of the deposits suggest that they mainly are polymetallic veins of Late Triassic or younger age.
  • Age = Late Triassic or younger.

Economic information about the deposit and operations

Development status Prospect

Mining district

District name Ketchikan

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)

Reporter information

Type Date Name Affiliation Comment
Reporter 05-JUL-99 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.