Sea Breeze

The Sea Breeze is a gold mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Sea Breeze

Commodity

Primary: Gold
Secondary: Zinc
Secondary: Lead

Location

State: Alaska
District: Ketchikan

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Low-sulfide Au-quartz vein

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: The walls of some of the veins are bluish-gray, hydrothermally altered rock that was interpreted by the early miners as a dike, or dikes, of intrusive porphyry ('blue porphyry' of Brooks, 1902, p. 65-67; and Wright and Wright, 1908, p. 144-146). Maas and others (1995, p. 215), however, interpret it as a zone of hydrothermally altered mafic metavolcanic rock.

Rocks

Not available

Analytical Data

Not available

Materials

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

Comments

Comment (Reference): Primary Reference = Brooks, 1902; Maas and others, 1995

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.? the Sea Breeze claim adjoins the Sea Level claim (KC095) on the northeast, and is located on the extension of its mineralized belt (Brooks, 1902, p. 67; Wright and Wright, 1908, p. 146; Maas and others, 1995, fig. 55). The deposit consists of quartz fissure veins 1-8 feet thick in mafic metavolcanic (greenstone) country rock. The veins strike NE and dip steeply SE, and are sharply discordant to the NW foliation of the metavolcanic country rocks. The veins are characterized by intense fracturing, brecciation, and abrupt variations in mineralization. The ore minerals include [auriferous] pyrite, galena, sphalerite, and an occasional speck of native gold. Auriferous pyrite also is sparsely disseminated in the wallrocks adjacent to the veins (Maas and others, 1995, p. 215). The walls of some of the veins are bluish-gray, hydrothermally altered rock that was interpreted by the early miners as a dike, or dikes, of intrusive porphyry ('blue porphyry' of Brooks, 1902, p. 65-67; and Wright and Wright, 1908, p. 144-146). Maas and others (1995, p. 215), however, interpret it as a zone of hydrothermally altered mafic metavolcanic rock.? Maas and others (1995) also report that the quartz in the veins is not recrystallized. The veins thus probably are younger than most or all of the Late Cretaceous regional metamorphism, but are older than a period of intense local faulting and brecciation.? the prospect was explored in the early 1900s by two short tunnels, and by numerous opencuts that exposed the veins for several hundred feet along strike. Maas and others (1995, p. 218) report two adits, one 69 feet long, and one caved. Maas and others (1995, p. 217-218) report a mean value of 661 ppb Au in 12 samples of the Sea Breeze vein. Their best assay showed 2.0 ppm Au in an 8.5-foot sample across the vein.

Comment (Workings): Workings / Exploration = The prospect was explored in the early 1900s by two short tunnels, and by numerous opencuts that exposed the veins for several hundred feet along strike. Maas and others (1995, p. 218) report two adits, one 69 feet long, and one caved. Maas and others (1995, p. 217-218) report a mean value of 661 ppb Au in 12 samples of the Sea Breeze vein. Their best assay showed 2.0 ppm Au in an 8.5-foot sample across the vein.

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

Comment (Geology): Age = Maas and others (1995) report that the quartz in the veins is not recrystallized. The veins thus probably are younger than most or all of the Late Cretaceous regional metamorphism, but are older than a period of intense local faulting and brecciation.

References

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): 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): 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.

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.

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