|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||Fourth Beach is the highest elevation auriferous strandline now known on the Nome coastal plain (Hopkins and others, 1960; Nelson and Hopkins, 1972; Tagg and Greene, 1973; Cobb, 1973 [B 1374, figure 29, p. 87]). The elevation of the Fourth Beach strandline is 125 feet. It is preserved at the base of Anvil Mountain, where it is buried by colluvium. The map location is about on Cooper Gulch at a surface elevation of 250 feet. It is in the west-central part of section 12, T. 11 S., R. 34 W., Kateel River Meridian. The location is accurate within about 500 feet.|
Geologic descriptionFourth Beach represents the farthest advance of the sea in Quaternary time, and it has been recognized only at the base of Anvil Mountain. It formed as a true strandline beach by waves impinging upon bedrock. Unlike Third Beach, which terminates landward on a prominent scarp marked by long-continued erosion at that sea level, Fourth Beach is an inconspicuous strandline that evidently formed during a relatively short seastand. It is not generally rich enough to mine. Probably some of the gold that was concentrated at Fourth Beach sea level was eroded seaward before the beach was buried by mass-wasting deposits. Hopkins and others (1960, p. 47-48) noted that the sediments of Fourth Beach are overlain by drift of the Nome River glaciation and that the seaward edge of the deposits is truncated at the Third Beach escarpment. They postulated that Fourth Beach may have formed during some part of Submarine Beach time or during an otherwise unidentified interglacial interval. Nelson and Hopkins (1972) diagrammatically show Fourth Beach at the base of Anvil Mountain (also see Cobb, 1973 [B 1374, figure 29]).
|Geologic map unit||(-165.388300981609, 64.5500344152968)|
|Mineral deposit model||Placer Au; buried, strandline beach deposit (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Pleistocene.|
|Workings or exploration||There is no substantial production from Fourth Beach. Gold originally concentrated on this beach could have been eroded and reconcentrated in alluvial deposits below the beach.|
|Indication of production||None|
Additional commentsConsidered too low grade to be of economic interest.
Hopkins, D.M., MacNeil, F.S. and Leopold, E.B., 1960, The coastal plain at Nome, Alaska, A late Cenozoic type section for the Bering Sea region, in Chronology and climatology of the Quaternary: International Geological Congress, 21st, Copenhagen, Proceedings, Part 4, p. 46-57.
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.
|Reporters||C.C. Hawley and Travis L. Hudson|
|Last report date||7/10/2000|