Sunday Lake Prospect, Bokan Mountain, Prince of Wales Island, Ketchikan Mining District, Prince of Wales-Hyder Census Area, Alaska, USAi
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Latitude & Longitude (WGS84):
54° 55' 46'' North , 132° 10' 19'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Location: The Sunday Lake prospect is at an elevation of about 750 feet, about 1.2 miles northwest of Bokan Mountain and about 0.7 mile east-southeast of the center of section 17, T. 80 S., R. 88 E. Its location relative to the other uranium and REE prospects in the vicinity of Bokan Mountain is best shown on Plate 1 of MacKevett (1963).
Geology: This and several other nearby uranium-thorium-REE deposits (DE015, DE016, and DE18 to DE031) are spatially and genetically related to a stock of Jurassic, peralkaline granite about 2 miles in outcrop diameter centered on Bokan Mountain. It commonly is referred to as the Bokan Mountain peralkakline granite or Bokan Mountain complex. The intrusion and its deposits have been mapped in detail several times using slightly different subdivisions of the granite (MacKevett, 1963; Thompson and others, 1980, 1982; Saint-Andre and others, 1983; Gehrels, 1992; Thompson, 1997). This description largely follows Gehrels' (1992) map units. The intrusion is a ring-dike complex with an outer border zone up to 14 meters thick of pegmatite and aplite; a nearly complete intermediate zone of aegirine granite porphyry, 15 to 180 meters thick; and a core of several varieties of riebeckite granite porphyry. It has been dated by several methods at 151 Ma to 191 Ma (Lanphere and others, 1964; Saint-Andre and others, 1983; Armstrong, 1985; Gehrels, 1992; Thompson, 1997). The peralkaline granite mainly intrudes a regionally extensive body of Silurian or Ordovician quartz monzonite, granite, and quartz diorite that makes up much of the southeast tip of Prince of Wales Island. The south and west sides of the peralkaline granite are in contact with a band up to about 3,000 feet wide of shale and argillite of the Silurian or Ordovician Descon Formation. The Bokan Mountain complex and surrounding Paleozoic rocks are cut by numerous pegmatite, andesite, dacite, and aplite dikes. The dikes are genetically related to the complex and commonly are associated with the uranium, thorium, and REE deposits. The deposits are marked by intense albitization, pervasive or fracture-controlled chloritization, calcite-fluorite replacement of aegirine, and hematitization. Three types of U-Th-REE deposits occur in the Bokan Mountain complex: 1) irregular cylindrical pipes; 2) steep, shear-zone-related pods or lenses ('veins'); and 3) quartz veins. The Sunday Lake prospect consists of two short trenches and a small pit (Warner and Barker, 1989). The deposit is controlled by steeply dipping, north-northwest-trending shear zones and fractures which can be traced for about 300 feet in riebeckite granite. Allanite is locally abundant. Where exposed, the deposit is 3 to 7 feet thick and consists of highly radioactive, mottled, iron- and manganese-stained gouge and crushed rock. According to Warner and Barker (1989), the deposit has an inferred resource of 27,000 short tons of material that contains 26,000 pounds of columbium, 1,728,000 pounds of thorium, 270,000 pounds of uranium, 437,000 pounds of yttrium, 151,000 pounds of zirconium.
Workings: Two short trenches and a small prospect pit.
Age: Genetically related to the Jurassic, Bokan Mountain peralkaline granite.
Alteration: This prospect and the other uranium, thorium, and REE deposits associated with the Bokan Mountain peralkaline granite are marked by albitization, chloritization, and argillization. Minor calcite, fluorite, quartz, sulfide minerals, and tourmaline are common in the altered rocks and hematite often occurs in the periphery of high-grade ore zones.
Reserves: According to Warner and Barker (1989), the deposit has an inferred resource of 27,000 short tons of material that contains 26,000 pounds of columbium, 1,728,000 pounds of thorium, 270,000 pounds of uranium, 437,000 pounds of yttrium, 151,000 pounds of zirconium.
Commodities (Major) - Cb, REE, Th, U, Y, Zr
Deposit Model: U-Th-REE deposit associated with peralkaline granite.
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
Detailed Mineral List:
| ⓘ 'Allanite Group' Formula: (A12+REE3+)(M13+M23+M32+)O[Si2O7][SiO4](OH) |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Unclassified | |||
|---|---|---|---|
| ⓘ | 'Allanite Group' | - | (A12+REE3+)(M13+M23+M32+)O[Si2O7][SiO4](OH) |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Allanite Group | (A12+REE3+)(M13+M23+M32+)O[Si2O7][SiO4](OH) |
| O | Oxygen | |
| O | ⓘ Allanite Group | (A12+REE3+)(M13+M23+M32+)O[Si2O7][SiO4](OH) |
| Si | Silicon | |
| Si | ⓘ Allanite Group | (A12+REE3+)(M13+M23+M32+)O[Si2O7][SiO4](OH) |
Other Databases
| Link to USGS - Alaska: | DE017 |
|---|
Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Alexander DomainDomain
- Alexander TerraneVolcanic Arc
- Queen Charlotte basinBasin
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