Unnamed Prospect (ARDF - SI012; north shore of outer Bertha Bay), Chichagof Mining District (Chicagof Mining District), Sitka, Alaska, USAi
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Latitude & Longitude (WGS84):
57° 48' 24'' North , 136° 21' 18'' West
Latitude & Longitude (decimal):
Köppen climate type:
Mindat Locality ID:
202386
Long-form identifier:
mindat:1:2:202386:4
GUID (UUID V4):
7bc56eb7-65aa-4a34-bd83-bcf40a7efd95
The prospect is in West Chichagof-Yakobi Wilderness.
Location: This prospect is at sea level at the north mouth of Bertha Bay. The prospect is at the head of a small bay just east of Pt. Dougherty, and 0.4 mile southwest of the center of sec. 9, T. 47 S., R. 56 E. It is location P-41 of Bittenbender and others (1999), location 15 of Cobb (1972, 1978), and MAS no. 0021140014 (U.S. Bureau of Land Management, 2002). The location is accurate within about 0.5 mile.
Geology: Johnson and Karl (1985) map the rocks in the area of this prospect as Cretaceous graywacke that is intruded by Tertiary gabbronorite and tonalite, and cut by high-angle faults that mainly strike northwest. The graywacke is thermally metamorphosed to hornfels near the contact of the gabbronorite and tonalite. The deposit consists of stringers of chalcopyrite and pyrrhotite in mafic intrusive rock (gabbronorite?) near its contact with the metamorphosed country rock. Bittenbender and others (1999) interpret the prospect as a magmatic segregation deposit, presumably similar to the one at Bohemia Basin (SI001).
Age: Assuming that the deposit is a magmatic segregation, it is Tertiary, the age of the gabbronorite(?) host rock.
Alteration: Thermal metamorphism of country rocks.
Commodities (Major) - Cu
Development Status: None
Deposit Model: Duluth Cu-Ni-PGE? (Cox and Singer, 1986; model 5a).
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:
| ⓘ Chalcopyrite Formula: CuFeS2 |
| ⓘ Pyrrhotite Formula: Fe1-xS |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| ⓘ | Pyrrhotite | 2.CC.10 | Fe1-xS |
List of minerals for each chemical element
| S | Sulfur | |
|---|---|---|
| S | ⓘ Chalcopyrite | CuFeS2 |
| S | ⓘ Pyrrhotite | Fe1-xS |
| Fe | Iron | |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Pyrrhotite | Fe1-xS |
| Cu | Copper | |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
Other Databases
| Link to USGS - Alaska: | SI012 |
|---|
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References
