SM Occurrence, Chistochina Mining District, Southeast Fairbanks Census Area, Alaska, USAi
| Regional Level Types | |
|---|---|
| SM Occurrence | Occurrence |
| Chistochina Mining District | Mining District |
| Southeast Fairbanks Census Area | Census Area |
| Alaska | State |
| USA | Country |
This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84):
63° 10' 56'' North , 144° 28' 4'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
The unpublished data that is cited can be seen by contacting Grayd Resources Inc. in Vancouver, B.C., Canada (www.grayd.com), or Northern Associates Inc. in Fairbanks, Alaska.
Location: The SM occurrence is on a nunatak and is accessible only by helicopter (R.A. Blakestad and others, unpublished Resource Associates of Alaska Inc. report, 1978). The occurrence is at an elevation of about 6,600 feet; it is one-half mile east of peak 7140 in the NE1/4 section 9, T. 16 N., R. 5 E., Copper River Meridian. The location is accurate.
Geology: The SM occurrence is in the Hayes Glacier unit of Devonian to Mississippian age (Nokleberg and others, 1992) and consists of a folded exposure of 7 feet of massive sulfides exposed on a nunatak. At least four distinct types of massive sulfide mineralization are found in glacial debris below the nunatak. These include: (1) banded pyrite-sphalerite-galena(-chalcopyrite), (2) massive pyrite, (3) massive pyrrhotite with minor chalcopyrite and pyrite, and (4) banded pyrite and sphalerite in a matrix of black graphitic siltstone. The abundance of each of these types of mineralization suggests that a substantial deposit may be present under the glacial ice. Isoclinal folding is prominent in outcrop. The massive sulfides occur at the contact between a pyritic and sericitic, felsic metavolcanic layer and a black graphitic siltstone. This contact appears to be repeated in several locations on the nunatak (R.A. Blakestad and others, unpublished Resource Associates of Alaska Inc. report, 1978). Average metal values of the massive sulfide were 0.26 percent copper, 0.27 percent lead, 2.97 percent zinc, 0.62 ounce of silver per ton, and 0.05 ounce of gold per ton (R.A. Blakestad and others, unpublished Resource Associates of Alaska Inc. report, 1978). The Hayes Glacier rocks that host the SM occurrence consists of fine-grained phyllitic schists and mylonite derived from sedimentary and volcanic protoliths. The rocks locally display intense structural deformation due to their proximity to the Denali Fault. The rocks are metamorphosed to lower greenschist facies and are less metamporphosed than Jarvis Belt rocks to the northeast (Nokleberg and others, 1992). The basal part of the unit consists of mafic to intermediate composition metavolcanic rocks overlain by interbedded felsic metavolcanic units and extensive pelitic and graphitic metasedimentary rocks (Dashevsky and others, 2003).
Workings: This prospect was staked in 1976 by Resource Associates of Alaska, and limited exploration followed. Some sampling and a few lines of magnetic and VLF geophysical surveys were run. Strong anomalies from both techniques were found to correlate with known mineralization. A hand-held drill was used to sample banded, pyritic massive sulfide outcrops at the northeastern corner of the SM nunatak to a maximum depth of 4 feet.
Age: Devonian to Mississippian, on the basis of the age of the host rocks.
Commodities (Major) - Zn; (Minor) - Ag, Au, Cu, Pb
Development Status: None
Deposit Model: Kuroko massive sulfide (Cox and Singer, 1986; model
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
6 valid minerals.
Detailed Mineral List:
| ⓘ Chalcopyrite Formula: CuFeS2 |
| ⓘ Galena Formula: PbS |
| ⓘ Graphite Formula: C |
| ⓘ Pyrite Formula: FeS2 |
| ⓘ Pyrrhotite Formula: Fe1-xS |
| ⓘ Sphalerite Formula: ZnS |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Graphite | 1.CB.05a | C |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Sphalerite | 2.CB.05a | ZnS |
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| ⓘ | Pyrrhotite | 2.CC.10 | Fe1-xS |
| ⓘ | Galena | 2.CD.10 | PbS |
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
List of minerals for each chemical element
| C | Carbon | |
|---|---|---|
| C | ⓘ Graphite | C |
| S | Sulfur | |
| S | ⓘ Chalcopyrite | CuFeS2 |
| S | ⓘ Galena | PbS |
| S | ⓘ Pyrite | FeS2 |
| S | ⓘ Pyrrhotite | Fe1-xS |
| S | ⓘ Sphalerite | ZnS |
| Fe | Iron | |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Pyrite | FeS2 |
| Fe | ⓘ Pyrrhotite | Fe1-xS |
| Cu | Copper | |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
| Zn | Zinc | |
| Zn | ⓘ Sphalerite | ZnS |
| Pb | Lead | |
| Pb | ⓘ Galena | PbS |
Other Databases
| Link to USGS - Alaska: | MH316 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- North America PlatformPassive Margin
- Windy-McKinley DomainDomain
This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to
visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders
for access and that you are aware of all safety precautions necessary.