Hecla Prospect, Prince William Sound Mining District, Valdez-Cordova Census Area, Alaska, USAi
Regional Level Types | |
---|---|
Hecla Prospect | Prospect |
Prince William Sound Mining District | Mining District |
Valdez-Cordova Census Area | Census Area |
Alaska | State |
USA | Country |
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Latitude & Longitude (WGS84):
61° 8' 2'' North , 146° 39' 54'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
Place | Population | Distance |
---|---|---|
Valdez | 3,870 (2017) | 17.0km |
Mindat Locality ID:
197935
Long-form identifier:
mindat:1:2:197935:3
GUID (UUID V4):
137d79f8-7c33-49eb-9da7-950d6d5a9ee0
Location: This prospect is on the ridge crest at the head of McAllister Creek; it is at an elevation of 1,900 feet just northeast of the center of section 33, T. 8 S., R. 8 W., of the Copper River Meridian. This prospect is probably located to within one-quarter mile. It is locality 9 of Cobb and Matson (1972) and locality 6 of Winkler and others (1981 [OFR 80-892-B]).
Geology: Shear zones as much as 8 feet thick with irregularly distributed gold-bearing quartz lenses cut metaflysch of the Valdez Group (Brooks, 1912). The quartz lenses also contain arsenopyrite, pyrite, and galena. These mineralized zones are probably similar to other gold-bearing quartz veins cutting metaflysch of the Valdez Group in the southern Valdez quadrangle. Data summarized by Goldfarb and others (1997) show that gold-bearing quartz veins in the Valdez Group commonly contain pyrite, arsenopyrite, carbonate minerals, chlorite, and white mica and formed from water-rich fluids with 5 to 15 mole percent CO2 and significant amounts of CH4, N2, and H2S. The vein-forming fluid salinities were less than 8 percent, vein formation temperatures ranged from 225 to 375 degrees centigrade, and emplacement depths varied from 3 to 10 kilometers. The vein-forming fluids were produced by metamorphic devolatization reactions. Radiometric dating indicates that the veins formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171), when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Workings: At least surface exploration has taken place on this prospect; two claims were staked. and the shear zone was reported to have been traced for about one-half mile (Brooks, 1912).
Age: Radiometric dating indicates that the gold-bearing quartz veins in the Valdez Group formed from 57 to 49 Ma (Goldfarb and others, 1997, p. 171), when deep parts of the accreted Valdez Group flysch underwent high-grade metamorphism and partial melting (Hudson, 1994).
Alteration: Country rocks to gold-bearing quartz veins in Valdez Group metaflysch can be variably silicified, carbonitized, and sericitized (Goldfarb and others, 1997).
Commodities (Major) - Au; (Minor) - Ag, Pb
Development Status: Undetermined.
Deposit Model: Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
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
7 valid minerals.
Detailed Mineral List:
ⓘ Arsenopyrite Formula: FeAsS |
ⓘ Calcite Formula: CaCO3 |
ⓘ 'Chlorite Group' |
ⓘ Galena Formula: PbS |
ⓘ Gold Formula: Au |
ⓘ Muscovite Formula: KAl2(AlSi3O10)(OH)2 |
ⓘ Muscovite var. Sericite Formula: KAl2(AlSi3O10)(OH)2 |
ⓘ Pyrite Formula: FeS2 |
ⓘ Quartz Formula: SiO2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
Group 1 - Elements | |||
---|---|---|---|
ⓘ | Gold | 1.AA.05 | Au |
Group 2 - Sulphides and Sulfosalts | |||
ⓘ | Galena | 2.CD.10 | PbS |
ⓘ | Pyrite | 2.EB.05a | FeS2 |
ⓘ | Arsenopyrite | 2.EB.20 | FeAsS |
Group 4 - Oxides and Hydroxides | |||
ⓘ | Quartz | 4.DA.05 | SiO2 |
Group 5 - Nitrates and Carbonates | |||
ⓘ | Calcite | 5.AB.05 | CaCO3 |
Group 9 - Silicates | |||
ⓘ | Muscovite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
ⓘ | var. Sericite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
Unclassified | |||
ⓘ | 'Chlorite Group' | - |
List of minerals for each chemical element
H | Hydrogen | |
---|---|---|
H | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
H | ⓘ Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
C | Carbon | |
C | ⓘ Calcite | CaCO3 |
O | Oxygen | |
O | ⓘ Calcite | CaCO3 |
O | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
O | ⓘ Quartz | SiO2 |
O | ⓘ Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
Al | Aluminium | |
Al | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
Al | ⓘ Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
Si | Silicon | |
Si | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
Si | ⓘ Quartz | SiO2 |
Si | ⓘ Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
S | Sulfur | |
S | ⓘ Arsenopyrite | FeAsS |
S | ⓘ Galena | PbS |
S | ⓘ Pyrite | FeS2 |
K | Potassium | |
K | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
K | ⓘ Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
Ca | Calcium | |
Ca | ⓘ Calcite | CaCO3 |
Fe | Iron | |
Fe | ⓘ Arsenopyrite | FeAsS |
Fe | ⓘ Pyrite | FeS2 |
As | Arsenic | |
As | ⓘ Arsenopyrite | FeAsS |
Au | Gold | |
Au | ⓘ Gold | Au |
Pb | Lead | |
Pb | ⓘ Galena | PbS |
Other Databases
Link to USGS - Alaska: | VA091 |
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Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Chugach DomainDomain
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