|Quadrangle map, 1:250,000-scale||NM|
|Quadrangle map, 1:63,360-scale||C-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Butterfield Canyon is a south tributary to Bangor Creek, a west tributary to Snake River. The confluence of Butterfield Canyon and Bangor Creek is about 2.8 miles due west of the Snake River road. The lower 2,000 feet of Butterfield Canyon has been placer mined. The map site is on Butterfield Creek, in the SE1/4 section 21, T. 9 S., R. 34 W., Kateel River Meridian. It is included in locality 92 of Cobb (1972 [MF 463], 1978 [OFR 78-93]). The confluence of Butterfield and Bangor Creeks is covered by patented mining claims (U.S. Mineral Survey No. 1844); the plat shows placer workings on both Bangor and Butterfield Creeks.|
Butterfield Creek has been placer mined for approximately 2,000 feet above its confluence with Bangor Creek (NM192). The source of the placer gold appears to be lode deposits at an elevation of 400 to 500 feet southeast of the placer workings. This zone is marked by scattered boulders of white quartz with 1 to 2 percent disseminated galena and a 2,000-foot-long, east-west-oriented soil anomaly containing as much as 895 ppb gold and 3,720 ppm arsenic (Kennecott Exploration Company, written communication, 1993). The anomaly terminates sharply upslope, suggesting an east-west linear source.
The placer deposit appears to have contained sulfidized albite. A small dump on the south side of the creek mainly contains auriferous, iron-stained albite. The dump probably represents either placer clean-up or tailings from a hard-rock mill or arrastre. The presence of auriferous albite suggests that the source of the placer gold is of the albite-rich type like that at Twin Mountain (NM186), Goodluck Gulch (NM202), and Sophie Gulch (NM208). Rocks such as these could have also contributed scheelite that is reported to be abundant in Bangor Creek below its confluence with Butterfield Creek (Thorne and others, 1948). Most of the mining along Butterfield Creek was probably done around 1900 by shovel-in methods.Country rock is calcareous metaturbidite schist (Bundtzen and others, 1994). This schist is composed mainly of quartz, calcite, feldspar, mica and opaques. Graphitic quartz schist crops out on the southeast flank of the creek near the upper limit of placer pay.
|Geologic map unit||(-165.485212951463, 64.6888346385117)|
|Mineral deposit model||Alluvial placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||Butterfield Creek was worked largely by hand methods above its confluence with Bangor Creek. The creek was probably mined mainly before 1930. In 1992, Kennecott Exploration Company mapped the geology and collected soil samples in the area and found an extensive gold anomaly on the flank of Butterfield Creek above the placer mine; this zone is almost certainly part of the source of the pay in Butterfield and Bangor Creeks.|
|Indication of production||Yes; small|
Bundtzen, T.K., Reger, R.D., Laird, G.M., Pinney, D.S., Clautice, K.H., Liss, S.A., and Cruse, G.R., 1994, Progress report on the geology and mineral resources of the Nome mining district: Alaska Division of Geological and Geophysical Surveys, Public Data-File 94-39, 21 p., 2 sheets, scale 1:63,360.
Cobb, E.H., 1972, Metallic mineral resources map of the Nome quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-463, 2 sheets, scale 1:250,000.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Nome quadrangle, Alaska: U.S. Geological Survey Open-File report 78-93, 213 p.
|Reporters||C.C. Hawley and Travis L. Hudson|
|Last report date||7/10/2000|