Goo Goo Extension

Site Name

Primary: Goo Goo Extension
Secondary: Majestic
Secondary: Mother Lode

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Commodity

Primary: Gold
Secondary: Zinc
Secondary: Lead

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Location

State: Alaska
District: Ketchikan

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Land Status

Not available

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Holdings

Not available

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Workings

Not available

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Ownership

Not available

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:

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Physiography

Not available

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Mineral Deposit Model

Model Name: Low-sulfide Au-quartz vein

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Orebody

Not available

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Structure

Not available

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Alterations

Alteration Type: L
Alteration Text: The Goo Goo Extension vein, like most of the other principal veins in the Sea Level mine area, is 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.

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Rocks

Not available

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Analytical Data

Not available

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Materials

Ore: Galena
Ore: Gold
Ore: Pyrite
Ore: Sphalerite
Gangue: Quartz

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Comments

Comment (Deposit): Other Comments = Early reports refer to this property as the Majestic or Mother Lode claim.

Comment (Deposit): Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Comment (Production): Production Notes = Combined recorded production from the Goo Goo Extension and Goo Goo (KC096) claims, probably all in the early 1900s, was 1.4 kg of gold (Maas and others, 1995, p. 218).

Comment (Reference): Primary Reference = Wright and Wright, 1908; Maas and others, 1995

Comment (Workings): Workings / Exploration = Workings in the early 1900s consisted of an open pit 10 feet deep, and a tunnel 10 feet long. At that time, a picked sample assayed $30 Au/ton (Au at $20.67/ounce) (Brooks, 1902, p. 67). Maas and others (1995, p. 217) report a mean value of 959 ppb Au in 24 samples of the Goo Goo Extension vein. Private examination in the early-mid-1980s of an 1837-foot adit on the Goo Goo Extension claim outlined five zones of elevated gold values, mainly along the margins of the vein(s) (Maas and others, 1995, p. 215).

Comment (Geology): 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.? Wright and Wright (1908, p. 147) describe this deposit as a 20-foot-thick quartz fissure vein in altered schists. The vein, which they suggest is a continuation of the Goo Goo vein (KC096), strikes N63E, and contains pyrite, sphalerite, and galena. Workings in the early 1900s consisted of an open pit 10 feet deep, and a tunnel 10 feet long. At that time, a picked sample assayed $30 Au/ton (Au at $20.67/ounce) (Brooks, 1902, p. 67). Maas and others (1995, p. 217) report a mean value of 959 ppb Au in 24 samples of the Goo Goo Extension vein. Private examination in the early-mid-1980s of an 1837-foot adit on the Goo Goo Extension claim outlined five zones of elevated gold values, mainly along the margins of the vein(s) (Maas and others, 1995, p. 215).? Maas and others (1995, p. 216) provide the following combined description of an auriferous quartz fissure vein more than 4900 feet long on the Goo Goo Extension claim and its continuation northeastward onto the adjoining Goo Goo claim (KC096). The vein, which strikes NE and dips steeply SE, is in mafic metavolcanic rocks and, in addition to free gold, contains pyrite, sphalerite, and galena. Hydrothermally altered metavolcanic rock adjacent to the vein contains disseminated pyrite and accompanying gold values (see Alteration). The best results of sampling in 1946 included: 5.8 ppm Au in a section of vein 7.5 feet thick and 79 feet long; and 7.1 ppm Ag in a section of vein 4.6 feet thick and 25 feet long. Thirty-one samples of the vein collected by Maas and others (1995) contained an average of 1.1 ppm Au. The workings, which date from the early 1900s, include 2 adits, one 1800 feet long and one caved; one flooded shaft; and several surface trenches and pits. Combined recorded production from the claims, probably all in the early 1900s, was 1.4 kg of gold. Maas and others' description of the Goo Goo and Goo Goo Extension vein indicates that its character and setting are virtually identical to the main vein on the Sea Level claim (KC095).

Comment (Geology): 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.

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References

Reference (Deposit): Crawford, M.L., Crawford, W.A., and Gehrels, G.E., 2000, Terrane assembly and structural relationships in the eastern Prince Rupert quadrangle, British Columbia, in H.H. Stowell and W.C.McClelland, eds., Tectonics of the Coast Mountains, southeastern Alaska and British Columbia: Boulder, Colorado, Geological Society of America Special Paper 343, p. 1-21.?

Reference (Deposit): Wright, F.E., and Wright, C.W., 1908, The Ketchikan and Wrangell mining districts, Alaska: U.S. Geological Survey Bulletin 347, 210 p.

Reference (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.

Reference (Deposit): Berg, H.C., 1982, The Alaska Mineral Resource Assessment Program; guide to information about the geology and mineral resources of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Circular 855, 24 p.

Reference (Deposit): Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

Reference (Deposit): Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.

Reference (Deposit): Brooks, A.H., 1902, Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska: U.S. Geological Survey Professional Paper 1, 120 p.

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