Keystone (ARDF #AN045) Au

Keystone

Prospect, Inactive

Commodities and mineralogy

Main commodities	Au
Ore minerals	gold
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	AN
Quadrangle map, 1:63,360-scale	D-6
Latitude	61.8
Longitude	-149.24
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	On mountainside west of Sydney Creek, approximately 1 mile southwest of the confluence of Sydney Creek with Archangel Creek. This is locality 24 from Figure 9 (Cohen, 1982). Accurate within 1,000 feet.

Geologic setting

Geologic description Details about the prospect are unavailable. Most likely, a gold-bearing quartz vein(s) cuts the Late Cretaceous Willow Creek Pluton. The Willow Creek Pluton is a zoned pluton. The outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite.
Geologic map unit	(-149.242210151643, 61.7994709534638)
Mineral deposit model	Low-sulfide Au-quartz veins? (Cox and Singer, 1986; model 36a?).
Mineral deposit model number	36a?
Age of mineralization	Late Cretaceous or younger; the host of mineralization is the Late Cretaceous Willow Creek Pluton.

Production and reserves

Workings or exploration	Apparently only minor surface prospecting.
Indication of production	None

References

MRDS Number	A106230
Reporters	D.P. Bickerstaff (USGS contractor)
Last report date	7/30/1998