|Quadrangle map, 1:250,000-scale||NM|
|Quadrangle map, 1:63,360-scale||C-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Twin Mountain Creek (shown as Twin Mtn Ck onthe map) is a north tributary of Boulder Creek. Boulder Creek is a west tributary to Snake River; it flows east from headwaters in the eastern Nome C-2 quadrangle. Twin Mountain Creek and a series of west side benches were placer mined. The upper part of Twin Mountain Creek is on the Nome C-1 quadrangle (where it is shown as Twin Mountains Creek). The location used here is about the mid-point of placered ground on Twin Mountain Creek. Twin Mountain Creek is locality 94 of Cobb (1972 [MF 463], 1978 [OFR 78-93]); his map location is at the confluence of Twin Mountain and Boulder Creeks.|
A shallow placer deposit on Twin Mountain Creek (shown as Twin Mtn Ck on the map) just above Boulder Creek was worked in 1903 and earlier, but apparently without profit (Collier and others, 1908, p. 197). Prospecting during World War I resulted in discovery of scheelite, which was mined by placer mining methods in the bench deposits on the west side of the creek (Mertie, 1918 [B 662-I, p. 437, 455, 457]). About 500 pounds of scheelite were recovered from a bench claim opposite claim No. 4 Above Discovery, a location almost 1 mile above Boulder Creek. Coats (1944) proposed that Twin Mountain Creek could contain significant amounts of scheelite. Some activity in Twin Mountain Creek took place as late as 1953 when eight 'Yellow Bird' claims were staked (Heiner and Porter, 1972, Kardex site Kx-52-1).
Exploration and mapping since 1953 indicates that Twin Mountain Creek flows through a significantly mineralized area. Pan concentrate samples collected at the mouth of Twin Mountain Creek and its two uppermost tributaries by Kennecott Exploration Company in 1990 and 1991 contained more than 10,000 ppb gold. A north-northeast-trending soil geochemistry grid was sampled in 1992; the north half of the grid is approximately bisected by Twin Mountain Creek (Kennecott Exploration Company, written communication, 1992). This survey showed that soils extending northward from the Boulder Creek prospect (NM165) almost to Butterfield Creek and along the west side of the Twin Mountain Creek valley are moderately to strongly enriched in gold and arsenic and locally enriched in lead, zinc, and antimony. As the result of the soil survey, several new hard-rock mineral occurrences were found. The most significant was the Twin Mountain prospect at the head of Twin Mountain Creek (Bundtzen and others, 1994, sheet 1 of 2). Because of heavy soil cover and solifluction lobes on the slopes immediately above Twin Mountain Creek, it is not possible to exactly limit the eastern extent of the soil anomaly, but it is generally parallel to Twin Mountain Creek and appears to be located on the Rodine fault. These deposits are probably the sources of the placer deposits in Twin Mountain Creek. Some deposits, such as the scheelite deposit opposite No. 4 Above Discovery, are essentially residual placer deposits.Twin Mountain Creek also generally parallels the Twin Mountain antiform, a structure that exposes biotite schist in the bottom of the valley. This biotite schist has tentatively been correlated with metamorphic rocks underlying the Nome Group (Bundtzen and others, 1994).
|Geologic map unit||(-165.502708920852, 64.6598331396192)|
|Mineral deposit model||Alluvial placer Au-W and residual deposits (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||Gold was discovered and some was placer mined in Twin Mountain Creek (shown as Twin Mtn Ck on the map) in 1900 (Brooks and others, 1901, p. 80). The lower part of the creek was mined unsuccessfully before 1903. Other mining took place in 1916 when scheelite was sluiced from residual placer deposits on the west side of Twin Mountain Creek. Placer claim activity occurred as recently as 1953 (Heiner and Porter, 1972). A large soil geochemistry survey was completed in the area in 1992.|
|Indication of production||Yes; small|
|Production notes||At least 500 pounds of scheelite were produced from the residual placers on the benches west of Twin Mountain Creek.|
|MRDS Number||A012893; D002580|
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.
Coats, R.R., 1944, Lode scheelite occurrences of the Nome area: U.S. Geological Survey Open-File Report 17, 6 p.
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.
Heiner, L.E., and Porter, Eve, 1972, Alaska Mineral Properties, volume 2: University of Alaska, Mineral Industry Research Laboratory Report 24, 669 p.
|Reporters||C.C. Hawley and Travis L. Hudson|
|Last report date||3/12/2000|