|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||The Last Chance prospect is on the south side of the headwaters of Last Chance Creek at an elevation of about 650 feet. This is 1 mile northeast of the divide between Last Chance Creek and Penny River. The prospect is located to within about 500 feet. It is the same prospect as locality 19 of Cobb (1972 [MF 463], 1978 [OFR 78-93]) but Cobb's location is about a half mile too far to the east.|
Geologic descriptionThe Last Chance prospect consists of an adit driven south-southwest on the Penny River fault or a splay of the fault. The prospect was first reported by Smith (1908, p. 345). Mertie (1918 [B 662-I, p. 446]) also mentions it ,but it appears unlikely that the prospect was visited by the U.S. Geological Survey at that time. The vein at the prospect was variously reported as 4 or 5 feet wide. It contained galena, pyrite, and stibnite with quartz and ankerite. Gold and silver were reported in assays, but the presence of native gold is uncertain. A 70-foot adit was driven on the vein. It is inferred from the lack of further development that the gold content of the vein was low, but there is abundant quartz float at the prospect. Sainsbury and others (1972 [OFR 72-321]) show placer gold mine workings to be present on Last Chance Creek for about 1 mile downstream from near this prospect. The prospect was relocated by a Kennecott Exploration Company in 1990; it is similar to the nearby Christophosen prospect (NM143). Country rock at the prospect is the chlorite-rich metaturbidite and marble unit of Bundtzen and others (1994).
|Geologic map unit||(-165.540718048951, 64.7207351398559)|
|Mineral deposit model||Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).|
|Mineral deposit model number||36a|
|Age of mineralization||Mid-Cretaceous or younger; host structure crosscuts rocks metamorphosed in the mid-Cretaceous.|
|Workings or exploration||The prospect was discovered by G. Christophosen, who was apparently very active in the area before 1915 (see also NM141 and NM143). A 70-foot adit was driven on the vein. It is inferred from the lack of further development that the gold content of the vein was low,but there is abundant quartz float at the prospect. The vein is in a strong structure.|
|Indication of production||Undetermined|
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.
Mertie, J.B., Jr., 1918, Lode mining and prospecting on Seward Peninsula, in Brooks, A.H., and others, Mineral resources of Alaska, report on progress of investigations in 1916: U.S. Geological Survey Bulletin 662, p. 425-449.
Sainsbury, C.L., Hudson, T.L., Ewing, Rodney, and Marsh, W.R., 1972, Reconnaissance geologic map of the Nome C-2 quadrangle, Seward Peninsula, Alaska: U.S. Geological Survey Open-File Report 72-321, 13 p., 1 sheet, scale 1:63,360.
|Reporters||C.C. Hawley and Travis L. Hudson|
|Last report date||3/12/2000|