Unnamed Occurrence (ARDF - BH027; west of Aniak River), Aniak Mining District, Dillingham Census Area, Alaska, USAi
| Regional Level Types | |
|---|---|
| Unnamed Occurrence (ARDF - BH027; west of Aniak River) | - not defined - |
| Aniak Mining District | Mining District |
| Dillingham Census Area | Census Area |
| Alaska | State |
| USA | Country |
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Latitude & Longitude (WGS84):
60° 43' 11'' North , 159° 7' 11'' West
Latitude & Longitude (decimal):
Köppen climate type:
Location: This occurrence is at an elevation of about 1800 feet, approximately 2.3 miles west-northwest of hill 3127 ('Obvious'). The map site is on the northwest-trending ridge, in the SW1/4 of sec. 4, T 7 N, R 56 W, of the Seward Meridian. The site corresponds to locality 8 of Frost (1990, fig. 1). The location is probably accurate to within 1 or 2 miles.
Geology: Quartz and tourmaline variably replace plagioclase porphyry at this occurrence (Frost, 1990, p. C4). Incipient alteration includes tourmaline replacement of plagioclase phenocrysts and quartz replacement of groundmass. More-extensively altered rocks are granular aggregates of fine-grained quartz and clumps of tourmaline. Some rocks are made up of alternating quartz-rich and tourmaline-rich layers. The altered rocks weather as bright red, vegetation-free areas. Rock samples contain up to 70 ppm Ag, 2,000 ppm As, greater than 2,000 ppm B, 500 ppm Cu, 7,000 ppm Pb, 7,000 ppm Sb, 1,000 ppm Zn, and 4.4 ppm Hg (Frost, 1990; Frost and others, 1992). Gold was detected at 0.10 ppm in one sample. The occurrence is at least 100 meters above the base of the Kipchuk volcanic field, a large area of Upper Cretaceous andesite, basalt, tuff, and local rhyolite in the uplands between the Kipchuk and Aniak River drainages (Box and others, 1993).
Workings: Reconnaissance surface observation and geochemical sampling has occurred at this site.
Age: Post-Late Cretaceous. Quartz and tourmaline replace volcanic rocks of the Kipchuk volcanic field that locally yield 69 to 71 Ma K/Ar ages (Box and others, 1993).
Alteration: Quartz and tourmaline replacement, oxidation.
Commodities (Major) - Ag, Cu, Hg, Pb, Sb, Zn; (Minor) - Au
Development Status: None
Deposit Model: Polymetallic veins (Cox and Singer, 1986; model 22c).
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
1 valid mineral.
Detailed Mineral List:
| ⓘ Quartz Formula: SiO2 |
| ⓘ 'Tourmaline' Formula: AD3G6 (T6O18)(BO3)3X3Z |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 4 - Oxides and Hydroxides | |||
|---|---|---|---|
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| Unclassified | |||
| ⓘ | 'Tourmaline' | - | AD3G6 (T6O18)(BO3)3X3Z |
List of minerals for each chemical element
| B | Boron | |
|---|---|---|
| B | ⓘ Tourmaline | AD3G6 (T6O18)(BO3)3X3Z |
| O | Oxygen | |
| O | ⓘ Quartz | SiO2 |
| O | ⓘ Tourmaline | AD3G6 (T6O18)(BO3)3X3Z |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
Other Databases
| Link to USGS - Alaska: | BH027 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Koyukuk ArcsVolcanic Arc
- Walrus-Togiak DomainDomain
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