Unnamed Occurrence (ARDF - ID146; near hill 2825 on Granite Mountain), Iditarod Mining District, Yukon-Koyukuk Census Area, Alaska, USAi
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Latitude & Longitude (WGS84):
62° 19' 4'' North , 156° 43' 55'' West
Latitude & Longitude (decimal):
Köppen climate type:
Location: This occurrence is at an elevation of about 2,600 feet, about 0.7 mile southwest of peak 2923, the top of Granite Mountain. It is about 0.3 mile north of the center of section 29, T. 26 N., R. 40 W., of the Seward Meridian. The location is accurate.
Geology: This occurrence, also referred to as the Granite Mountain prospect (Bundtzen and Miller, 1997) consists of several sizable bodies of metasomatic axinite, anatase, and tourmaline at the contact between the Granite Mountain pluton and hornfelsed rocks derived from the Upper cretaceous Kuskokwim Group. The occurrence includes: 1) zones of tourmaline-bearing sheeted veins, 2) tourmaline-cemented breccias in hornfels; and 3) axinite-tourmaline-sulfide replacement bodies in both intrusive rocks and in hornfels. The nearby Granite Mountain pluton has a 40K/40Ar age of 62.6 Ma (Bundtzen and Miller, 1997). One large area of boron-rich tourmaline-axinite-anatase greisen is 1,300 feet long, about 50 feet wide, and cylindrical in cross section; it may contain 5.5 million tons of boron-enriched material of unknown grade. This zone also contains disseminated gray sulfide minerals. Grab samples from the occurrence contained 100 parts per million (ppm) tin, 500 parts per billion (ppb) silver, 50 ppb gold, 9.0 ppm bismuth, 28 ppm antimony, 80 ppm arsenic, and more than 2,000 ppm boron (McGimsey and others, 1988; Bundtzen and Miller, 1997).
Workings: Samples were collected by the U.S. Geological Survey and Alaska Division of Geological and Geophysical Surveys in 1984 (McGimsey and others, 1988; Bundtzen and Miller, 1997).
Age: The nearby Granite Mountain pluton has a A 40K/40Ar age of 62.6 Ma (Bundtzen and Miller, 1997).
Alteration: Development of axinite-tourmaline-quartz greisen.
Commodities (Major) - Ag, Sn; (Minor) - As, Au, Bi, Sb
Development Status: None
Deposit Model: Sn-polymetallic deposit or Polymetallic vein (Cox and Singer, 1986; model 20b o
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
2 valid minerals.
Detailed Mineral List:
| ⓘ Anatase Formula: TiO2 |
| ⓘ 'Axinite Group' |
| ⓘ 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 |
| ⓘ | Anatase | 4.DD.05 | TiO2 |
| Unclassified | |||
| ⓘ | 'Tourmaline' | - | AD3G6 (T6O18)(BO3)3X3Z |
| ⓘ | 'Axinite Group' | - | |
List of minerals for each chemical element
| B | Boron | |
|---|---|---|
| B | ⓘ Tourmaline | AD3G6 (T6O18)(BO3)3X3Z |
| O | Oxygen | |
| O | ⓘ Anatase | TiO2 |
| O | ⓘ Quartz | SiO2 |
| O | ⓘ Tourmaline | AD3G6 (T6O18)(BO3)3X3Z |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
| Ti | Titanium | |
| Ti | ⓘ Anatase | TiO2 |
Other Databases
| Link to USGS - Alaska: | ID146 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Farewell buried DomainDomain
- Farewell TerranePassive Margin
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