Logan Beach

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Fe; Mo
Ore minerals native gold
Gangue minerals garnet; magnetite

Geographic location

Quadrangle map, 1:250,000-scale YA
Quadrangle map, 1:63,360-scale D-5
Latitude 59.82
Longitude -139.592
Nearby scientific data Find additional scientific data near this location
Location and accuracy Logan Beach is within Yakutat Bay, immediately south of Logan Bluffs; it extends about 2 miles north and 3 miles south of cited coordinate location which is in section 21, T. 24 S., R. 34 E., of the Copper River Meridian. The locality is number 3 of Cobb (1972).

Geologic setting

Geologic description

Logan beach is a wave-cut beach formed from gravelly terrace deposits of glacial material which form the bluffs behind the beach. The bedrock on the upland hills to the east of the deposit consists of graywacke and argillite of the Yakutat Group of Jurassic and Cretaceous age (MacKevett and Plafker, 1970). At the beach, gold occurred in thin transient deposits enriched in garnet or magnetite; the beach placer was derived by winnowing wave-action on weakly auriferous glacial gravels.
The placer could also contain reworked materials brought down from the Jura-Cretaceous bedrock. MacKevett and Plafker (1970, pl. 1) report anomalous amounts of molybdenum (3 to 10 ppm) in two stream sediment samples from the Logan Beach. Molybdenum is commonly enriched in organic shales as well as granitic rocks, but its source in the bedrock behind the Logan Beach is unknown.
Reimnitz and Plafker (1976, pl. I) reported 0.010 ppm gold in one sample from the beach.
Geologic map unit (-139.593694276043, 59.8196962855753)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Holocene

Production and reserves

Workings or exploration Surface workings, rockers and sluices. The occurrence is one of the first placers discovered in the Yakutat quadrangle (Tarr, 1906; Tarr and Butler, 1909).
Indication of production Yes; small
Production notes The beach had a very limited production, with a maximum of a few hundred ounces of gold.

Additional comments

The Logan beach placer is within the Russell Fiord Wilderness area of Tongass National Forest.

References