Unnamed Occurrence (ARDF - JU024; northwest shore of outer Adams Inlet), Glacier Bay Mining District, Juneau Mining District, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - JU024; northwest shore of outer Adams Inlet)	- not defined -
Glacier Bay Mining District	- not defined -
Juneau Mining District	Mining District
Alaska	State
USA	Country

Location: This occurrence is on the north shore of Adams Inlet, approximately 3 miles from its entrance. It is in the NW1/4 section 6, T. 35 S., R. 57 E. of the Copper River Meridian. The location is accurate within 1/4 mile.
Geology: The rocks in the area consist of deformed and metamorphosed Silurian or Devonian carbonate, clastic and volcanic clastic units that have been intruded by Upper Jurassic and Lower Cretaceous granitic and dioritic rocks (Brew and others, 1992). Lava flows of amygdaloidal, vesicular, altered basalt up to 15 feet thick are exposed for 500 feet along the shore at this site. Pyrite, chalcopyrite, and pyrrhotite occur along fractures in the basalt and near altered basalt dikes which intrude the flows. Pyrite, ilmenite, and magnetite are disseminated throughout the dikes (Brew and others, 1978). The groundmass of the altered basalt consists of epidote, actinolite, and lesser amounts of calcite, dolomite, and chlorite. All samples collected contained anomalous amounts of copper; one sample contained 300 ppm cobalt. Most samples contained trace amounts of molybdenum; one contained silver and tin (MacKevett and others, 1971).
Workings: Surface sampling only.
Alteration: Propylitization of basalt hostrock.

Commodities (Major) - Cu; (Minor) - Ag, Co, Mo, Sn
Development Status: None
Deposit Model: Volcanic-hosted Cu (Cox and Singer, 1986; model 22a)

Other Databases

Link to USGS - Alaska:	JU024

Other Regions, Features and Areas containing this locality

References