Collapse pit along Florence Trend shear zone, Keystone district.
Collapse pit along Florence
Trend shear zone,
Keystone district.

Keystone District

The Keystone district, about three miles southeast of the New Rambler district, hosts lode gold mineralization concentrated along northwest-trending shears that cut quartz diorite, quartz-biotite schist, and foliated granodiorite. These shears, subsidiary to the Mullen Creek-Nash Fork shear zone, provide loci for quartz veins and veinlets and copper-gold mineralization with associated epidotization of wallrock (Hausel, 1989). Currey (1965) estimated the total lode gold production from the mines in the Keystone district at about 8,500 ounces.

Further information on the Douglas Creek, Keystone, and New Rambler districts can be found in the following WSGS publications:

WSGS Preliminary Report 3, The Keystone gold-copper prospect area, Albany County, Wyoming, by Donald R. Currey (1965), map scale 1:26,250, 12 p.

WSGS Preliminary Report 8, The New Rambler copper-gold-platinum district, Albany and Carbon Counties, Wyoming, by M.E. McCallum and C.J. Orback (1968), map scale ~1:26,000, 12 p.

WSGS Open File Report 05-6, Preliminary geologic map of the Keystone Quadrangle, Albany and Carbon counties, Wyoming (Link to Geologic Mapping page) by Wayne M. Sutherland and W. Dan Hausel (2005), map, scale 1:24,000, 21 p.