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High Horse

Prospect in Alaska, United States with commodities Gold, Zinc
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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 10001593
MRDS ID A012351
Record type Site
Current site name High Horse
Alternate or previous names Monster

Geographic coordinates

Geographic coordinates: -131.18287, 55.36669 (WGS84)
Relative position The High Horse claim is in section 18, T. 75 S., R. 94 E., of the Copper River Meridian. It straddles Gokachin and Sea Level creeks, just upstream from their confluence. The map site represents the approximate center of the claim as shown in Wright and Wright (1908, fig. 12). The site corresponds to loc. 98 in Elliott and others (1978). The location is accurate within about 0.25 mile. ? 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 B-4(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
Gold Primary
Zinc Critical Secondary

Materials information

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

Alteration

  • (Local) Most of the principal veins in the Sea Level mine area are bordered by a hydrothermally altered zone up to three feet thick, characterized by generally fine-grain, light-gray to bluish-gray, massive, carbonate- and sericite-bearing rock that commonly contains cubic pyrite crystals up to an inch across (Maas and others, 1995, p. 215). Maas and others (1995) interpret this zone as hydrothermally altered mafic metavolcanic rock. Early miners called this altered rock 'blue porphyry,' which they interpreted as crosscutting altered dikes that predate the quartz veins, but are closely associated with some of the orebodies (Brooks, 1902, p. 65; Wright and Wright, 1908, p. 143). Gold content of these pyritic altered zones is high adjacent to the quartz veins and diminishes away from them. Weathered altered rocks have a reddish-brown, oxidized rind up to three inches thick.

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 > Schist

Nearby scientific data

(1) -131.18287, 55.36669
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The country rocks in this part of Revillagigedo Island are marine, interbedded, andesitic and basaltic metavolcanic rocks and subordinate pelitic metasedimentary rocks that are intruded by stocks, sills, and dikes of Cretaceous feldspar-porphyritic granodiorite (Berg and others, 1988). The strata and some of the granodiorite were regionally metamorphosed to greenschist grade in Late Cretaceous time. These regionally metamorphosed rocks subsequently were locally remetamorphosed to hornblende hornfels near the contacts of Cretaceous granodiorite plutons that were emplaced after the regional metamorphism. The premetamorphic age of the strata is uncertain. Berg and others (1988) assign them a Mesozoic or (late) Paleozoic age. Berg (1982) and Crawford and others (in press) assign them to the Gravina belt, of Late Jurassic or Cretaceous age, or to the Taku terrane, of late Paleozoic to Late Triassic age. The metamorphic and intrusive rocks locally are overlain by basalt and andesite lava flows of Quaternary or Tertiary age.? Brooks (1902, p. 68) describes the Monster (subsequently relocated as High Horse) deposit as a 12- to 20-foot-wide pegmatite dike that contains abundantly disseminated pyrite, but very low gold values. The dike cuts diabase schist, which also carries considerable pyrite near its contact with the pegmatite.? According to Wright and Wright (1908, p. 147-148), the High Horse prospect is an [auriferous] quartz fissure vein 6 inches to 3 feet thick that strikes N55E and dips 75SE. The vein is hosted by schists that strike N50W and dip 80NE. The ore consists chiefly of pyrite and sphalerite, and, reportedly, carries low values in gold. ? the foregoing descriptions, although scanty, suggest that the High Horse vein is similar in character and geologic setting to other auriferous quartz fissure veins in the Sea Level mine area (see KC095-098).? Maas and others (1995, p. 215) note that the quartz in the veins in the Sea Level mine area is not recrystallized; the veins thus are probably younger than most or all of the Late Cretaceous regional metamorphism.
  • Age = Maas and others (1995, p. 215) note that the quartz in the veins in the Sea Level mine area is not recrystallized; the veins thus are probably younger than most or all of the Late Cretaceous regional metamorphism.

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 = The deposit was explored in the early 1900s by opencuts and a short prospect tunnel.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Brooks, 1902; Wright and Wright, 1908;

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Deposit Other Comments = the High Horse claim is a relocation of the original Monster claim (Wright and Wright, 1908, p. 147).

Reporter information

Type Date Name Affiliation Comment
Reporter 04-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.