Rick's prospect (Rick's; Rick's Creek; Rick's Nickel; Nickel Creek; Nail Allochthon; Nail Ridge prospects), Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Rick's prospect (Rick's; Rick's Creek; Rick's Nickel; Nickel Creek; Nail Allochthon; Nail Ridge prospects)	Prospect
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

A Cr-Cu-Ag-As-Mg-Ni occurrence.

Mineralization is a sulfide deposit (Deposit Model: Disseminated sulfides and chromite in serpentinite allochthon).

Location: Rick's prospect is centered at VABM Nail, approximately 55 miles NE of Delta Junction. The prospect covers a 60-square-kilometer area situated on a 12 kilometer long ridge. The approximate center of the prospect is in SW¼NE¼ section 11, T2S, R14E, of the Fairbanks Meridian. Rick's Creek and Black Bear Creek drain the ridge to the NW for 9 to 12 miles towards the North Fork of the Salcha River. It is locality 2 of Cobb (1972), who summarized relevant references under the name 'Nickel Creek'.

Geology: Rick's Prospect is approximately 12 km long and 2 km wide. Foster and others (1979) describe the bedrock as greenschist to amphibolite facies rocks that have been intruded by Mesozoic and Tertiary igneous bodies. Locally, the area is overlain by Tertiary sedimentary and volcanic rocks. The stratigraphy of the ridge consists of metamorphic rocks overlain by siliceous carbonate rock with localized areas of intense Fe-staining and alteration. This is overlain by peridotite with localized phases of harzburgite, dunite, and serpentinite, and capped by gabbro and diorite rubble. The underlying metamorphic rocks contain cherts that have radiolaria and conodonts of Permian age. The gabbro and diorite contain disseminated magnetite with trace chalcopyrite. Both the peridotite and the underlying siliceous carbonate rock contain 0.25 to 4% disseminated chromite. Rare pods and schlieren of chromite have also been found. Cobb and Eberlein (1980) reported pods of high-grade chromite 1 foot in thickness and 3 feet in length. Chromian spinel is common in the weathered area of the siliceous carbonate rock. The chromian spinel is high in Al and Mg, and probably of no economic or industrial use. The underlying siliceous carbonate rocks contain areas of serpentinite that are interpreted to have been altered by a CO2-rich fluid and contain significant amounts of magnesite. Assays have revealed up to 17% MgO; a possible resource of magnesium. Throughout the ridge, numerous assay results revealed no significant amounts of Ni, Co, Au or PGE. One occurrence of small pods of azurite and malachite, less than 0.5 cm in diameter, was observed in Fe-stained siliceous carbonate. A sample of this material contained relict chromite and minor veinlets of serpentinite, and assayed 1.14% Cu, 6,800 ppm Sb, 174 ppm As, and 24.6 ppm Ag. The first published geologic description of the region was by Prindle (1905). Saunders (1965) performed a limited geochemical investigation of the prospect at the invitation of the then claim holder. Large-scale mapping of the area was completed by Weber and others (1979). The most recent detailed work on the ridge was completed in a joint effort by the Alaska Division of Geological & Geophysical Surveys, the U.S. Bureau of Mines, and the U.S. Geological Survey in 1983. Menzie and Foster (1979) reported some placer claim staking nearby on Rick's Creek and Black Bear Creek, which drain Nail Ridge to the northwest. No production has been reported for the area.

Workings: The first published geologic description of the prospect was by Prindle (1905). Saunders (1965) performed a limited geochemical investigation of the prospect at the invitation of the claim holder. Large-scale mapping of the area was completed by Weber and others (1978). The most recent detailed work on the ridge was by a joint effort in 1983 by the Alaskan Division of Geological and Geophysical Surveys, the U.S. Bureau of Mines, and the U.S. Geological Survey published by Southworth (1985). Menzie and Foster (1979) reported some placer claim staking nearby on Rick's Creek and Black Bear Creek, which drain Nail Ridge to the northwest.

Alteration: The peridotite contains areas of serpentinite. The underlying siliceous carbonate rocks also contain areas of serpentinite; interpreted to have been altered to serpentinite by a CO2-rich fluid.

Production: There has only been prospecting on Nail Ridge and on some placer claims nearby on Rick's Creek and Black Bear Creek, which drain Nail Ridge to the northwest.

Other Databases

Link to USGS - Alaska:	BD036

Other Regions, Features and Areas containing this locality

References