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RW Zone

Prospect in Alaska, United States with commodities Silver, Copper, Zinc, Gold
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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. 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 10308256
Record type Site
Current site name RW Zone

Geographic coordinates

Geographic coordinates: -136.40214, 59.39974 (WGS84)
Relative position The prospect is approximately 3.0 miles, N58E from the summit of Mt. Henry Clay in the SE1/4, section 33, T. 2 S., R. 53 E. of the Copper River Meridian. Its location is taken from 1999 press releases of Rubicon Minerals (http://www.rubiconminerals.com) where the RW Zone is described as being located 1,600 feet from the Main Zone (SK066) between the Little Jarvis and Main Zone (SK066) showings. Still and others (1991) use the name 'Little Jarvis' for mineral showings on both the east and west sides of the Little Jarvis Glacier and this can be confusing. From Rubicon's press releases, it appears that the 'Little Jarvis' of Still and others (1991) on the east side of the Little Jarvis Glacier is only about 600 feet from Rubicon's RW Zone. Due to their apparent proximity, they are considered here as a single prospect.

Site location context

Political divisions (FIPS codes)

Haines(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Skagway B-4(quadrangle 1:63,360 scale)

Skagway SE(quadrangle 1:100,000 scale)

Skagway C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Chilkat-Skagway Rivers(hydrologic unit)

Northern Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

BLM(Federal land areas administered by BLM)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Copper Primary
Zinc Critical Primary
Gold Secondary

Materials information

Materials Type of material
Barite Ore
Chalcopyrite Ore
Pyrite Ore
Sphalerite Ore
Chlorite Gangue
Quartz Gangue
Sericite Gangue

Alteration

  • (Local) Sericitic, chloritic. The stringer zone below the massive sulfide horizon is chloritically altered.

Mineral occurrence model information

Model code 184
USGS model code 28a
Deposit model name Massive sulfide, kuroko
Mark3 model number 93
Model code 91
USGS model code 24b
Deposit model name Massive sulfide, Besshi (Japanese deposits)
Mark3 model number 30

Nearby scientific data

(1) -136.40214, 59.39974
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = Exploration by Rubicon Minerals in 1998 and drilling in 1999 discovered massive sulfide mineralization at the RW Zone. The RW Zone prospect is near the center of a 5-mile-long northwester trend that extends from the unnamed occurrences (SK070) at the northwest end through this prospect (SK067) and the Main Zone/Palmer prospect (SK066) to the Red Creek prospect (SK063) at the southeast end. Rubicon interprets the trend to represent the apex of a shallowly plunging, northwest-trending antiform. Mineralization intercepted in drill holes occurs both as: 1) chalcopyrite-sphalerite massive-sulfide mineralization, and 2) chalcopyrite-bearing, stringer-zone mineralization within a zone of strong chloritic alteration. The massive-sulfide, drill-intercept thicknesses range from 7.2 feet to 15 feet and contain up to 13.48% zinc, 1.89% copper, 2.98 ounces of silver per ton, and 0.02 ounces of gold per ton. Massive-sulfide drill intercepts extend over a dip length of 420 feet. The stringer-zone mineralization is beneath the massive sulfide horizon. One drill hole intercepted 156 feet of stringer-zone mineralization that included a 67.8-foot-thick interval with an average grade of 0.62% copper. Within the 67.8-foot-thick interval, there was a 16.2-foot interval that contained 1.50% copper. Surface samples from the nearby Little Jarvis prospect contain up to 13% zinc, 7% copper, and 7.0 ounces of silver per ton over a width of 15 feet. Rhyolites have been reported from the drill core. (Information summarized from Rubicon Minerals, 1998 and 1999). If the RW Zone and other similar prospects in the Mt. Henry Clay area are correlative with the Windy Craggy deposit in Canada and the Greens Creek deposit on Admiralty Island, then they are Late Triassic (Still, 1984 [OF 118-84]; Newberry and others, 1997).
  • Age = the RW Zone and other similar prospects in the Mt. Henry Clay area are probably correlative with the Windy Craggy deposit in Canada and the Greens Creek deposit on Admiralty Island and are therefore Late Triassic (Still , 1984 (OFR 118-84); Newberry and others, 1997).

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Active

Mining district

District name Juneau (Skagway subdistrict)

Comments on the workings information

  • Workings / Exploration = At least 6 holes were drilled on the prospect in 1999 by Rubicon Minerals. This was the first drilling in the Porcupine Creek - Mount Henry Clay area to intersect ore-grade thicknesses of massive-sulfide mineralization (Rubicon Minerals, 1999).

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Rubicon Minerals, 1999

General comments

Subject category Comment text
Deposit Model Name = Kuroko- or Besshi-type volcanogenic massive-sulfide deposit (Cox and Singer, 1986; models 28a or 24b).

Reporter information

Type Date Name Affiliation Comment
Reporter 04-FEB-01 T.C. Crafford T. Crafford & Associates

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

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