Unnamed Occurrence (ARDF - MG082; in Terra Cotta Mountains), McGrath Mining District, Bethel Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MG082; in Terra Cotta Mountains)	- not defined -
McGrath Mining District	Mining District
Bethel Census Area	Census Area
Alaska	State
USA	Country

Location: This unnamed occurrence is located in the Terra Cotta Mountains near the base of a northwesterly spur overlooking a north flowing, unnamed tributary of the South Fork of Kuskokwim River. It is at an elevation of 4,200 feet (1,280 m) in the NE1/4 sec. 12, T. 23 N., R. 23 W., of the Seward Meridian. The reporter visited the site in 1988; at station no. 88BT169.
Geology: This unnamed occurrence is a quartz-sulfide vein swarm in altered dacitic tuffs of the Eocene, Terra Cotta Volcanic Field (Bundtzen, Harris, and Gilbert, 1997). Most of the material is in the form of talus and no exposures of the veins were observed. Some sulfide zones have been transformed into extensive gossan. The extent of the mineralized area was not measured. One sample contained 240 ppb gold, 2,200 ppm arsenic, 880 ppm tungsten, 110 ppm cobalt, and 200 ppm antimony (Bundtzen, Harris, and Gilbert, 1997).
Workings: The reporter sampled the site in 1988 during geologic mapping for the Alaska Division of Geological and Geophysical Surveys (Bundtzen, Harris, and Gilbert, 1997). One sample contained 240 ppb gold, 2,200 ppm arsenic, 880 ppm tungsten, 110 ppm cobalt, and 200 ppm antimony.
Alteration: Extensive ferricrete gossan.
Reserves: None.

Commodities (Major) - As, Au, Sb, W; (Minor) - Co
Development Status: No
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c).

Other Databases

Link to USGS - Alaska:	MG082

Other Regions, Features and Areas containing this locality

References