Geologic description
Sledge Creek has been mined at the surface in a shallow deposit near where the creek emerges from the hills and enters the Snake River valley. Drift mining at two unknown locations was also reported by Mertie (1918 [B 662-I, p. 454]). Patented claim U.S. Mineral Survey No. 1343 is in lower Sledge Creek, immediately above the surface placer cut, and claim U.S. Mineral Survey No. 1840 is in the south fork of Sledge Creek. Gold and tungsten were reported at the former site (Heiner and Porter, 1972, Kardex site Kx 52-259). Tungsten in scheelite was also reported by Thorne and others (1948, p. 33) in Sledge Creek. Kennecott Exploration Company found gold in two pan concentrate samples collected 1,500 and 3,000 feet below the south fork junction. The samples, contained more than 4 and more than 2 ppm gold respectively. They also contained anomalous amounts of tin, suggesting that cassiterite is present. This placer deposit is at an elevation of 150 to 175 fee, suggesting that it may have been influenced by Quaternary sea-level changes during its development. Bedrock of the Sledge Creek drainage is mostly chloritic and calcareous schist. One or more branches of the Rodine fault parallel upper Sledge Creek (Bundtzen and others, 1994). At least some of the placer gold in Sledge Creek was probably derived from erosion of the Alpha Ridge deposit (NM171). |
