|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||This alluvial placer gold mine is in Grass Gulch, a west headwater tributary to Dexter Creek (NM303). The map location is at an elevation of about 450 feet in the SW1/4 section 31, T. 10 S., R. 33 W., Kateel River Meridian. Grass Gulch is included in locality 118 of Cobb (1972 [MF 463], 1978 [OFR 78-93]).|
Geologic descriptionGrass Gulch is one of several small headwater tributaries of Dexter Creek (NM303) that head in areas where high-level auriferous gravels have been mined (for example, NM246 and NM247). The Grass Gulch placer was small but very rich, and the entire 15 feet of rounded-pebble gravel and some clay was gold-bearing. The deposit apparently was worked out by 1903 from a 150-foot by 300- or 400-foot pit (Collier and others, 1908). Gold was also recovered from fractured and creviced marble bedrock. Overburden was only 2 feet of moss and soil, some of the gravel was frozen, and granite clasts were uncommon in the gravel (Collier and others, 1908; Moffit, 1913). Much of the placer gold in the headwaters of Dexter Creek, including Grass Gulch, is probably derived from reworking of the high-level gravels.
|Geologic map unit||(-165.351806730713, 64.5771360557321)|
|Mineral deposit model||Alluvial placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||A 150-foot by 300- or 400-foot pit removed the main deposit by 1903 and most of the rest of the deposit was mined out by 1909 (Collier and others, 1908; Henshaw, 1910).|
|Indication of production||Yes; small|
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.
Collier, A.J., Hess, F.L., Smith, P.S., and Brooks, A.H., 1908, The gold placers of parts of Seward Peninsula, Alaska, including the Nome, Council, Kougarok, Port Clarence, and Goodhope precincts: U.S. Geological Survey Bulletin 328, 343 p.
|Reporters||C.C. Hawley and Travis L. Hudson|
|Last report date||7/10/2000|