Unnamed Occurrence (ARDF - DE002), Wood Cove, Forrester Island, Forrester Island Wilderness, Ketchikan Mining District, Prince of Wales-Hyder Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - DE002)	- not defined -
Wood Cove	Cove
Forrester Island	Island
Forrester Island Wilderness	Wilderness Area
Ketchikan Mining District	Mining District
Prince of Wales-Hyder Census Area	Census Area
Alaska	State
USA	Country

NOTE: The occurrence is in the Forrester Island National Wildlife Refuge and is closed to exploration.

Location: This occurrence consists of two sample sites on the eastern shoreline of Forrester Island about 0.5 mile north of Wood Cove. They are near the center of section 30, T. 81 S., R. 80 E; the location is accurate.

Geology: During reconnaissance surveys in 1969, Clark and others (1971) identified a porphyry molybdenum deposit near Wood Cove on the north end of Forrester Island. A similar occurrence (DE001) is on the northern tip of Forrester Island. Forrester Island consists mainly of Cretaceous(?) diorite and quartz monzonite (Clark and others, 1971; Gehrels and Berg, 1992). At the northeast corner of the island, the pluton intrudes Silurian or Ordovician(?) conglomerate that has been metamorphosed near the pluton. At one location at this site, stockwork-type molybdenum-porphyry mineralization occurs in an area approximately 300 feet by 100 feet. The host rock varies from quartz monzonite to granodiorite; it is propylitically altered, strongly pyritized, and cut by numerous quartz veinlets containing molybdenite, epidote, and pyrite. The host rock also contains disseminated molybdenite, as well as small amounts of magnetite, chalcopyrite, and pyrrhotite. The molybdenum content of 11 samples varied from 5 to 500 parts per million (ppm) molybdenum with an average of about 200 ppm. At another locality, molybdenite occurs in quartz veins 1 to 6 inches thick that cut hornfelsed metaconglomerate near the contact with the pluton. Samples contained 500-700 ppm molybdenum.

Workings: There are no workings and probably no exploration has taken place.
Age: Probably related to the Cretaceous(?) diorite and quartz monzonite pluton that makes up most of Forrester Island.
Alteration: The quartz monzonite and diorite host rock has been strongly propylitized; the metaconglomerate adjacent to the pluton has been hornfelsed and is cut by numerous quartz veins.
Reserves: Clark and others (1971) suggest that the resource potential of these occurrences is extremely limited.

Commodities (Major) - Mo; (Minor) - Cu
Development Status: None
Deposit Model: Porphyry molybdenum (Cox and Singer, 1986; model 21b).

Other Databases

Link to USGS - Alaska:	DE002

Other Regions, Features and Areas containing this locality

References