Unnamed Occurrence (ARDF - ID139; south of hill 1735), Iditarod Mining District, Yukon-Koyukuk Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - ID139; south of hill 1735)	- not defined -
Iditarod Mining District	Mining District
Yukon-Koyukuk Census Area	Census Area
Alaska	State
USA	Country

Location: This occurrence is about 0.3 mile south of hill 1735, near the divide between head of Granite Creek and the Little East Fork of George River. The occurrence is at an elevation of about 1,400 feet, near the southwest corner of section 5, T. 26 N., R. 41 W., of the Seward Meridian. The location is accurate.
Geology: This occurrence is a quartz breccia zone with limonite and tourmaline in hornfelsed sandstone of the Upper Cretaceous, Kuskokwim Group, adjacent to a small body of biotite quartz monzonite. The mineralized breccia covers an area about 160 by 500 feet in area that is oriented northeast The monzonite contains a stockworks of numerous small quartz-tourmaline-sericite veins. The quartz monzonite is undated, but a similar intrusive body exposed about 0.3 mile to the south has a 40K/40Ar age of 71.1 Ma (Bundtzen, Miller, and Laird, 1986; Miller and Bundtzen, 1994; Miller, Bundtzen, and Gray, 2005). Grab samples of mineralization contained up to 1,000 parts per million (ppm) tin, 1,000 parts per billion (ppb) silver, 500 ppm copper, 350 ppm zinc, 100 ppm lead, 160 ppm arsenic, 54 ppm antimony, and 1,200 ppb mercury (McGimsey and others, 1988).
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). Battle Mountain Mining Company explored the occurrence in the late 1980s and drilled one diamond-drill hole; the results are confidential (Szumigala, 1993) Placer Dome U S flew an aeromagnetic survey over the Upper Granite Creek area but that survey has not been publicly released (L.E. Wyrick, oral communication, 2003).
Age: Undated; a similar intrusive of quartz monzonite exposed about 500 meters to the south has a 40K/40Ar age of 71.1 Ma (Bundtzen, Miller, and Laird, 1986; Miller and Bundtzen, 1994).
Alteration: Development of quartz-tourmaline-sericite greisen; iron-oxide alteration.

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

Other Databases

Link to USGS - Alaska:	ID139

Other Regions, Features and Areas containing this locality

References