Old Man Breccia Prospect, Yentna Mining District, Matanuska-Susitna Borough, Alaska, USAi
Regional Level Types | |
---|---|
Old Man Breccia Prospect | Prospect |
Yentna Mining District | Mining District |
Matanuska-Susitna Borough | Borough |
Alaska | State |
USA | Country |
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Latitude & Longitude (WGS84):
61° 56' 23'' North , 152° 19' 12'' West
Latitude & Longitude (decimal):
Type:
KΓΆppen climate type:
Mindat Locality ID:
199238
Long-form identifier:
mindat:1:2:199238:3
GUID (UUID V4):
65d78fa0-69c8-4e36-94de-fd757ba6d474
Location: Alaska Department of Natural Resources claim records show the prospect in a stream bed of a northern tributary to Old Man Creek, four to five miles up stream from the confluence of Old Man Creek with the Skwentna River in Sections 1 and 2, T. 21 N., R. 17 W.
Geology: A float sample of pyrrhotite-chalcopyrite-quartz-pyrite, that contained several ounces of gold, lead to the discovery of a breccia in siltstone, part of Upper Jurassic and Lower Cretaceous flysch (KJs) of the Kahiltna terrane. The breccia is exposed over an area approximately 105 feet x 90 feet. Within the breccia angular clasts of argillite from less than one inch up to a few inches long occur in a matrix of well-healed milky quartz and lesser carbonate. The quartz-argillite breccia forms sinuous, sub-vertical zones around large argillite blocks. Sulfides in breccia are sparse (generally less than 1% total) and consist of pyrrhotite pods +/- pyrite and chalcopyrite, and rare coarse-grained arsenopyrite. Veins of quartz-pyrrhotite-pyrite-chalcopyrite crosscut the breccia zone and vary from a few inches to 2 feet in thickness and contain occasional specks of visible gold. No obvious alteration occurs in the hanging wall (Cominco American Incorporated, unpublished reports,1986-1988).
Workings: Exploration work included mapping, rock chip geochemistry, grid soil sampling, grid magnetic and VLF geophysical surveys, and diamond drilling.
Alteration: Iron-oxide
Commodities (Major) - Au, Cu; (Minor) - Fe
Development Status: None
Deposit Model: Gold-bearing, sulfide breccia
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
5 valid minerals.
Detailed Mineral List:
β Chalcopyrite Formula: CuFeS2 |
β Gold Formula: Au |
β Pyrite Formula: FeS2 |
β Pyrrhotite Formula: Fe1-xS |
β Quartz Formula: SiO2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
Group 1 - Elements | |||
---|---|---|---|
β | Gold | 1.AA.05 | Au |
Group 2 - Sulphides and Sulfosalts | |||
β | Chalcopyrite | 2.CB.10a | CuFeS2 |
β | Pyrrhotite | 2.CC.10 | Fe1-xS |
β | Pyrite | 2.EB.05a | FeS2 |
Group 4 - Oxides and Hydroxides | |||
β | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
O | Oxygen | |
---|---|---|
O | β Quartz | SiO2 |
Si | Silicon | |
Si | β Quartz | SiO2 |
S | Sulfur | |
S | β Chalcopyrite | CuFeS2 |
S | β Pyrite | FeS2 |
S | β Pyrrhotite | Fe1-xS |
Fe | Iron | |
Fe | β Chalcopyrite | CuFeS2 |
Fe | β Pyrite | FeS2 |
Fe | β Pyrrhotite | Fe1-xS |
Cu | Copper | |
Cu | β Chalcopyrite | CuFeS2 |
Au | Gold | |
Au | β Gold | Au |
Other Databases
Link to USGS - Alaska: | TY025 |
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Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Farewell buried DomainDomain
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