Schaeffer Prospect, Aniak Mining District, Dillingham Census Area, Alaska, USAi

Regional Level Types
Schaeffer Prospect	Prospect
Aniak Mining District	Mining District
Dillingham Census Area	Census Area
Alaska	State
USA	Country

Location: The Schaeffer prospect is located on the ridge north of Cinnabar Creek (TA002). The map site is at an elevation of about 1,550 feet, in the NE1/4 of section 13, T 8 N, R 55 W, of the Seward Meridian. It is 0.8 mile southeast of Cinnabar Gulch (TA001). This is locality 2 of Cobb 1972 [MF 384]; 1976 [OF 76-606]).
Geology: This prospect was discovered by Russell Schaeffer in 1958 and subsequently explored by a few shallow, hand-dug (?) trenches (Sainsbury and MacKevett, 1965, p. 40). The deposit is cinnabar- and stibnite-bearing, quartz-cemented breccia of Triassic chert and siltstone. The breccia is irregular in thickness and trends N 20 W, parallel to bedding in the host rocks. Cinnabar and stibnite are irregularly disseminated in the breccia and locally replace quartz and breccia fragments; the owner reported to Sainsbury that fossils replaced by cinnabar had been found at this prospect. The richest ore contains 1 to 2 percent cinnabar. The breccia is limonite-stained, but pyrite and/or marcasite has only been observed in the altered siltstone.
Workings: A few shallow trenches were dug on this prospect.
Age: Cretaceous or Tertiary. Inferred to be similar in age to other mercury deposits of southwest Alaska that postdate deposition of mid-Cretaceous clastic sedimentary rocks and intrusion of Upper Cretaceous or Tertiary igneous rocks.
Alteration: Silicification and limonite-staining.

Commodities (Major) - Hg; (Minor) - Sb
Development Status: None
Deposit Model: Cinnabar and stibnite disseminated in quartz-cemented breccia (Hot-spring Hg ?;

Other Databases

Link to USGS - Alaska:	TA003

Other Regions, Features and Areas containing this locality

References