Unnamed Occurrence (ARDF - ID175; west of Julian Creek), Iditarod Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - ID175; west of Julian Creek)	- not defined -
Iditarod Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Location: This occurrence is on hill 1390 on the spur that trends northwest between Spruce and Julian Creeks. It is about 0.6 mile northeast of the center of section 34, T. 25 N., R. 44 W., of the Seward Meridian. The location is accurate.
Geology: This occurrence consists of arsenopyrite-bearing quartz veinlets in a sericitically altered, granodiorite intrusion in flysch of the the Upper Cretaceous, Kuskokwim Group (Miller and Bundtzen, 1994; Bundtzen and Miller, 1997; Miller, Bundtzen, and Gray, 2005). The intrusion has a 40K/40Ar age of 70.1 Ma. The quartz veinlets occur in an area about 130 feet square. Grab samples of the veins contained up to 10.0 parts per million (ppm) silver, 100 ppm tin, more than 2,000 ppm arsenic, 11.0 ppm bismuth, 3.3 ppm cadmium, and 12 ppm antimony (McGimsey and others, 1988). The mineralized zone is a possible source of the placer gold in Julian (ID177) and Spruce (ID176) Creeks.
Workings: Samples were collected by the U.S. Geological Survey and Alaska Division of Geological and Geophysical Surveys in the 1980s (McGimsey and others, 1988).
Age: Unknown; the host intrusion has a 40K/40Ar age of 70.1 Ma (Miller and Bundtzen, 1994).
Alteration: Sericitic alteration of granodiorite.

Commodities (Major) - Ag, Sn; (Minor) - As, Bi, Cd, Sb
Development Status: None
Deposit Model: Sn-polymetallic deposit or Polymetallic vein (Cox and Singer, 1986; model 20b o

Other Databases

Link to USGS - Alaska:	ID175

Other Regions, Features and Areas containing this locality

References