Joker Group Prospect, Circle Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Joker Group Prospect	Prospect
Circle Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Location: The Joker Group can be reached via an 8 mile long dirt road that starts in Circle Hot Springs. The claims are above the confluence of Bottom Dollar and Half -Dollar Creeks. The coordinates are for the approximate center of the Joker Group claims.
Geology: The bedrock in the Joker claims groups is primarily porphyritic igneous rock containing large K-spar phenocrysts. Visible gold is found in the quartz veins. Both lode and placer gold are found at these claims (Vetter, 1995). Wiltse and others (1995) mapped the bedrock in the area as Cretaceous chloritized porphyritic (hornblende) biotite monzogranite to syenogranite. They also mapped a mafic dike in the area of the 88 Group claims which is described as black to dark gray, aphanitic to slightly porphyritic, with major plagioclase, augite, hornblende and magnetite. The granite is exposed along several ditches where it is deeply weathered and fractured. Abundant visible gold is seen in the stockwork veining. The light yellow color of the gold suggests a high silver content. Placer gold from the creeks below has a fineness of 750. Sampling in the vicinity of the Joker claims failed to delineate any significant extent to the stockwork veining; however, the trend of the stockwork veining is parallel to the ditch exposure, which is not as continuous as that at the 88 Group (Bakke,1991).
Workings: Surface samples taken.
Age: Mineralization is later than the Cretaceous granitic host rocks.

Commodities (Major) - Au
Development Status: None

Other Databases

Link to USGS - Alaska:	CI030

Other Regions, Features and Areas containing this locality

References