Double Anchor; Alaska State Mines Extension Prospect, Hyder Mining District, Prince of Wales-Hyder Census Area, Alaska, USAi
Regional Level Types | |
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Double Anchor; Alaska State Mines Extension Prospect | Prospect |
Hyder Mining District | Mining District |
Prince of Wales-Hyder Census Area | Census Area |
Alaska | State |
USA | Country |
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Latitude & Longitude (WGS84):
56° 3' 50'' North , 130° 15' 28'' West
Latitude & Longitude (decimal):
Type:
KΓΆppen climate type:
Nearest Settlements:
Place | Population | Distance |
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Stewart | 496 (2013) | 22.0km |
Mindat Locality ID:
197259
Long-form identifier:
mindat:1:2:197259:0
GUID (UUID V4):
b0e67688-764e-44ee-80e6-e2d6e7d458e0
Four claims were recorded in 1923; property was restaked in 1958 as part of the Alaska State Mines Extension claim group of 19 lode and 2 placer claims. The claims were inactive in 1973 (Berg and others, 1977, p. 76).
Location: The Double Anchor prospect is in Section 16 at an elevation of about 4100 feet near the top of a south-facing mountainside overlooking Texas Lake, about 0.7 mile south of the lake (Berg and others, 1977, p. 79; Elliott and Koch, 1981, p. 11, loc. 30).
Geology: The country rocks in the area near the Double Anchor prospect are pelitic metasedimentary and minor andesitic metavolcanic strata of the Jurassic or older Mesozoic Hazelton Group; the Triassic Texas Creek Granodiorite, which underlies and locally intrudes the Hazelton; and the Eocene Hyder Quartz Monzonite, which cuts both the Hazelton and Texas Creek rocks (Smith, 1977; Koch, 1996). Buddington (1929, p. p. 98-99) describes the deposit as a subhorizontal shear zone in argillite and graywacke that contains seams and stringers of quartz and sulfides, including sphalerite, galena, pyrite, chalcopyrite, and sparse pyrrhotite. The largest orebody is about 2.5 feet thick and 30 feet long; most individual veins are less than an inch thick. Thick quartz veins nearby are only sparsely mineralized. Berg and others (1977, p. 38-39) describe two quartz breccia zones. One is subhorizontal, up to about a foot thick, and exposed for about 700 feet along strike; the other dips steeply and is exposed for about 160 feet along strike. Both zones contain pyrite, galena, sphalerite, and chalcopyrite. The weighted average of analyses of samples collected by the U.S. Bureau of Mines in 1972 (Berg and others, 1977, p. 79-84) across about a two-foot-width of the main (subhorizontal) orebody is 4.3% Pb, 1.0% Zn, and 3.5 oz Ag and 0.022 oz Au per ton. Lead-isotope studies of galena from the Double Anchor prospect have yielded Jurassic and Eocene ages (Maas and others, 1995, p. 235, 244). The deposit is interpreted to be polygenetic, originating during Jurassic Hazelton island-arc volcanism (Alldrick, 1993), and then partly remobilized or reconstituted as fissure veins during Eocene emplacement of the Hyder Quartz Monzonite.
Workings: Prospect was explored, probably in the 1920's, by pits and short adits. The weighted average of analyses of samples collected by the U.S. Bureau of Mines in 1972 (Berg and others, 1977, p. 79-84) across about a two-foot-width of the main (subhorizontal) orebody is 4.3% Pb, 1.0% Zn, and 3.5 oz Ag and 0.022 oz AU per ton.
Age: Lead-isotope studies of galena from the Double Anchor prospect have yielded Jurassic and Eocene ages (Maas and others, 1995, p. 235, 244). The deposit is interpreted to be polygenetic, originating during Jurassic Hazelton island-arc volcanism (Alldrick, 1993), and then partly remobilized or reconstituted during Eocene emplacement of the Hyder Quartz Monzonite.
Alteration: Local intense iron staining. The subhorizontal quartz breccia zone is oxidized.
Commodities (Major) - Ag, Au, Cu, Pb, Zn; (Minor) - Cu
Development Status: None
Deposit Model: Polymetallic veins
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
5 valid minerals.
Detailed Mineral List:
β Chalcopyrite Formula: CuFeS2 |
β Galena Formula: PbS |
β Pyrite Formula: FeS2 |
β Quartz Formula: SiO2 |
β Sphalerite Formula: ZnS |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
Group 2 - Sulphides and Sulfosalts | |||
---|---|---|---|
β | Sphalerite | 2.CB.05a | ZnS |
β | Chalcopyrite | 2.CB.10a | CuFeS2 |
β | Galena | 2.CD.10 | PbS |
β | Pyrite | 2.EB.05a | FeS2 |
Group 4 - Oxides and Hydroxides | |||
β | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
O | Oxygen | |
---|---|---|
O | β Quartz | SiO2 |
Si | Silicon | |
Si | β Quartz | SiO2 |
S | Sulfur | |
S | β Chalcopyrite | CuFeS2 |
S | β Galena | PbS |
S | β Pyrite | FeS2 |
S | β Sphalerite | ZnS |
Fe | Iron | |
Fe | β Chalcopyrite | CuFeS2 |
Fe | β Pyrite | FeS2 |
Cu | Copper | |
Cu | β Chalcopyrite | CuFeS2 |
Zn | Zinc | |
Zn | β Sphalerite | ZnS |
Pb | Lead | |
Pb | β Galena | PbS |
Other Databases
Link to USGS - Alaska: | BC030 |
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