Breccia Occurrence (south of Snowcap Mountain), McGrath Mining District, Bethel Census Area, Alaska, USAi
Regional Level Types | |
---|---|
Breccia Occurrence (south of Snowcap Mountain) | Occurrence |
McGrath Mining District | Mining District |
Bethel Census Area | Census Area |
Alaska | State |
USA | Country |
This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84):
61° 25' 13'' North , 153° 34' 44'' West
Latitude & Longitude (decimal):
Type:
KΓΆppen climate type:
Mindat Locality ID:
196655
Long-form identifier:
mindat:1:2:196655:1
GUID (UUID V4):
aa839408-ac10-4b84-8cfc-691cce0d0c77
Location: This occurrence is at an elevation of about 4,500 feet on the east side of a small glacier, 2.9 miles southeast of Snowcap Mountain. It is in the SE1/4 section 4, T 15 N, R 24 W, of the Seward Meridian. The location is accurate to within 0.2 mile.
Geology: A tourmaline-cemented breccia as much as 80 feet across is present in monzogranite at this locality (Gamble and others, 1989). The breccia, includes vein quartz, light-colored angular rock fragments, and monzogranite clasts to about 3 feet across suspended in a black tourmaline matrix that also contains lesser amounts of sericite, quartz, calcite, and chlorite. Discontinuous quartz-tourmaline-sulfide veins to a foot wide cut the breccia along vertical, north-south-trending fractures. Sulfides in the veins include arsenopyrite, chalcopyrite, pyrrhotite, pyrite, and lesser amounts of galena and sphalerite; gangue minerals include quartz, tourmaline, chlorite, and epidote. A composite grab sample of 5 veins in the breccia contains as much as 4.1 ppm gold, 7 ppm silver,and greater than 2,000 ppm arsenic. Selected sulfide-rich samples contain as much as 21 ppm gold, 150 ppm silver, 10,000 ppm copper, and greater than 2,000 ppm arsenic and 1,000 ppm bismuth (Gamble and others, 1989).
Workings: Reconnaissance sampling has been done in this area (Gamble and others, 1989).
Age: Cretaceous or Tertiary? The breccia and veins crosscut granitic rocks that may be Late Cretaceous or Tertiary parts of the Alaska-Aleutian Range batholith.
Alteration: Tourmaline replacement and veining.
Commodities (Major) - Ag, Au, Cu; (Minor) - Bi
Development Status: None
Deposit Model: Tourmaline-cemented breccia in granitic rocks
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
10 valid minerals.
Detailed Mineral List:
β Arsenopyrite Formula: FeAsS |
β Calcite Formula: CaCO3 |
β Chalcopyrite Formula: CuFeS2 |
β 'Chlorite Group' |
β Epidote Formula: (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
β Galena Formula: PbS |
β Muscovite Formula: KAl2(AlSi3O10)(OH)2 |
β Muscovite var. Sericite Formula: KAl2(AlSi3O10)(OH)2 |
β Pyrite Formula: FeS2 |
β Pyrrhotite Formula: Fe1-xS |
β Quartz Formula: SiO2 |
β Sphalerite Formula: ZnS |
β 'Tourmaline' Formula: AD3G6 (T6O18)(BO3)3X3Z |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
Group 2 - Sulphides and Sulfosalts | |||
---|---|---|---|
β | Sphalerite | 2.CB.05a | ZnS |
β | Chalcopyrite | 2.CB.10a | CuFeS2 |
β | Pyrrhotite | 2.CC.10 | Fe1-xS |
β | Galena | 2.CD.10 | PbS |
β | Pyrite | 2.EB.05a | FeS2 |
β | Arsenopyrite | 2.EB.20 | FeAsS |
Group 4 - Oxides and Hydroxides | |||
β | Quartz | 4.DA.05 | SiO2 |
Group 5 - Nitrates and Carbonates | |||
β | Calcite | 5.AB.05 | CaCO3 |
Group 9 - Silicates | |||
β | Epidote | 9.BG.05a | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
β | Muscovite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
β | var. Sericite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
Unclassified | |||
β | 'Chlorite Group' | - | |
β | 'Tourmaline' | - | AD3G6 (T6O18)(BO3)3X3Z |
List of minerals for each chemical element
H | Hydrogen | |
---|---|---|
H | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
H | β Muscovite | KAl2(AlSi3O10)(OH)2 |
H | β Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
B | Boron | |
B | β Tourmaline | AD3G6 (T6O18)(BO3)3X3Z |
C | Carbon | |
C | β Calcite | CaCO3 |
O | Oxygen | |
O | β Calcite | CaCO3 |
O | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
O | β Muscovite | KAl2(AlSi3O10)(OH)2 |
O | β Quartz | SiO2 |
O | β Tourmaline | AD3G6 (T6O18)(BO3)3X3Z |
O | β Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
Al | Aluminium | |
Al | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
Al | β Muscovite | KAl2(AlSi3O10)(OH)2 |
Al | β Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
Si | Silicon | |
Si | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
Si | β Muscovite | KAl2(AlSi3O10)(OH)2 |
Si | β Quartz | SiO2 |
Si | β Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
S | Sulfur | |
S | β Arsenopyrite | FeAsS |
S | β Chalcopyrite | CuFeS2 |
S | β Galena | PbS |
S | β Pyrite | FeS2 |
S | β Pyrrhotite | Fe1-xS |
S | β Sphalerite | ZnS |
K | Potassium | |
K | β Muscovite | KAl2(AlSi3O10)(OH)2 |
K | β Muscovite var. Sericite | KAl2(AlSi3O10)(OH)2 |
Ca | Calcium | |
Ca | β Calcite | CaCO3 |
Ca | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
Fe | Iron | |
Fe | β Arsenopyrite | FeAsS |
Fe | β Chalcopyrite | CuFeS2 |
Fe | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
Fe | β Pyrite | FeS2 |
Fe | β Pyrrhotite | Fe1-xS |
Cu | Copper | |
Cu | β Chalcopyrite | CuFeS2 |
Zn | Zinc | |
Zn | β Sphalerite | ZnS |
As | Arsenic | |
As | β Arsenopyrite | FeAsS |
Pb | Lead | |
Pb | β Galena | PbS |
Other Databases
Link to USGS - Alaska: | LH026 |
---|
Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Farewell buried 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.