|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||The Snowflake placer mine is at Dexter, in the north headwaters of Dexter Creek (NM303). It is at an elevation of about 600 feet on the south side of the divide between Nekula Gulch and Deer Gulch. The map location is just inside the south-central boder of section 30, T. 10 S., R. 33 W., Kateel River Meridian. It is included in locality 117 (Dexter Hill) of Cobb (1972 [MF 463], 1978 [OFR 78-93]).|
The Snowflake mine is one of several near the divide between upper Anvil Creek (NM236) and Dexter Creek (NM303) at surface elevations of about 450 to 600 feet, where high-level gravels were placer mined for gold. These deposits were in gravels that ranged from a few feet to 150 feet thick and commonly were very rich (Brooks and others, 1901). The richest pay was near bedrock and in decomposed or fractured bedrock. The high-level gravels were mined mostly by drifting, but some hydraulic mining also took place. The section exposed in the main shaft of the Snowflake mine included 5 feet of muck and gravel containing granite and gneiss boulders above 125 feet of silt and gravel on bedrock; the lower 3 to 9 feet of gravel was auriferous. West of the shaft, the pay streak was 100 feet wide on bedrock but to the east this pay streak was on older gravels. A winze sunk 70 feet east of the main shaft reached bedrock 100 feet deeper, where another pay streak was developed on bedrock (Collier and others, 1908). The pay at the Snowflake mine ran about 0.3 ounce of gold per cubic yard; the gold was bright and subangular to crystalline (small octahedrons were visible), and some nuggets included fragments of quartz and calcite. The largest nugget recovered by 1903 weighed more than 9 ounces (Collier and others, 1908). The high-level gravels were originally interpreted to be alluvial deposits in stream channels of former drainage systems, but more recent interpretations describe them as glacial outwash-related material (Cobb, 1973 [B 1374]; Nelson and Hopkins, 1972). The presence of erratic granite boulders and other exotic rock types suggests a glacial origin, but the exotic clasts are commonly in near-surface materials and not distributed throughout the high-level gravels (Moffit, 1913). The origin of the high-level gravels thus still seems in question. The richness of some of the placers suggests extensive reworking, proximity to lode sources, or both.The Anvil fault transects the area near Nekula Gulch. The Anvil fault is a through-going, high-angle structure that juxtaposes different types of graphitic schist in this area (Hummel, 1962 [MF 247]). Bedrock is mostly graphitic schist, probably of early Paleozoic protolith age (Hummel, 1962, [MF 247]; Sainsbury, Hummel, and Hudson, 1972 [OFR 72-326]; Till and Dumoulin, 1994; Bundtzen and others, 1994).
|Geologic map unit||(-165.350007771564, 64.5857362669172)|
|Mineral deposit model||Alluvial placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||Workings at the Snowflake mine were underground. They included a 130-foot-deep main shaft, a winze sunk 70 feet east of the main shaft to the 230-foot level, and drifts trending N 60 W and S 60 E from the main shaft (Collier and others, 1908; Moffit, 1913).|
|Indication of production||Yes; small|
|Production notes||Production from the high-level gravels of the general area totaled about 100,000 ounces by 1903 (Collier and others, 1908). The pay ran about 0.3 ounce of gold per cubic yard at the Snowflake mine (Collier and others, 1908).|
Brooks, A.H., Richardson, G.B., Collier, A.J., and W.C. Mendenhall, 1901, A reconnaissance in the Cape Nome and adjacent gold fields of Seward Peninsula, Alaska, in 1900: U.S. Geological Survey Special Publication, p. 1-185, maps.
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.
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.
Hummel, C.L., 1962, Preliminary geologic map of the Nome C-1 quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-247, 1 sheet, scale 1:63,360.
Moffit, F.H., 1913, Geology of the Nome and Grand Central quadrangles, Alaska: U.S. Geological Survey Bulletin 533, 140 p.
Nelson, C.H., and Hopkins, D.M., 1972, Sedimentary processes and distribution of particulate gold in the northern Bering Sea: U.S. Geological Survey Professional Paper 689, 27 p., 1 plate.
Sainsbury, C.L., Hummel, C.L., and Hudson, Travis, 1972, Reconnaissance geologic map of the Nome quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 72-326, 28 p., 1 sheet, scale 1:250,000.
Till, A.B., and Dumoulin, J.A, 1994, Geology of Seward Peninsula and St. Lawrence Island, in Plafker, G., and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, v. G-1, p. 141-152.
|Reporters||C.C. Hawley and Travis L. Hudson|
|Last report date||7/10/2000|