Akwe Beach

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Au; Fe; Ti
Other commodities Cr; Zr
Ore minerals chromite; ilmenite; magnetite; native gold; rutile; zircon
Gangue minerals garnet

Geographic location

Quadrangle map, 1:250,000-scale YA
Quadrangle map, 1:63,360-scale B-4
Latitude 59.31
Longitude -139.14
Nearby scientific data Find additional scientific data near this location
Location and accuracy The placer extends along the Gulf of Alaska coast between the mouths of the Italio and Akwe Rivers; it is about 7 miles long. The coordinate location given is the approximate midpoint of the deposit which is partly in the Yakutat B-3 quadrangle. The deposit was noted by Cobb (1979, p. 17), and is Cobb's number 9 (1972).

Geologic setting

Geologic description

The Akwe beach placer is developed on a wide band of unconsolidated deposits of Holocene age (Foley and others, 1995, figure 4). These deposits formed in marine and terrestrial environments and are in unconformable contact with bedrock of Tertiary and older age (Reimnitz and Plafker, 1976, p. 4-8).
The placer deposits mostly consist of medium coarse sand. They formed in a high energy environment. The deposits are products of winnowing by strong tidal currents, storms, and generally northwest-moving long shore currents. In addition to deriving materials by reworking of the unconsolidated deposits, rivers and streams bring down a constant supply of alluvium that is reworked and stratified by size and density.
Deposits enriched in ilmenite and magnetite are locally preserved in uplifted strand lines back of the modern beaches. These enriched layers are relatively continuous and as much as several feet thick. Gold locally occurs with ruby and black sands on the modern beach in thin transient lenses and wedges. Zircon and rutile are locally enriched.
Samples collected at Akwe beach by Thomas and Berryhill (1962) contained as much as 5.3 pounds/cubic yard of titanium and 10.5 pounds/cubic yard of iron. Foley and others (1995) found gold, titanium, and zircon in samples from the Akwe beach.
The ultimate source of the heavy minerals enriched in the placers is in the hard rock deposits of the Fairweather Range.
Geologic map unit (-139.141710436931, 59.3097195800495)
Mineral deposit model Beach placer: ilmenite-based deposit, minor gold
Age of mineralization Holocene.

Production and reserves

Workings or exploration The area has been sampled fairly extensively by the Bureau of Mines in two investigations. Samples of beach sands collected by Thomas and Berryhill (1962, table 17, p. 30-33) contained as much as 5.3 pounds titanium/cubic yard, 10.5 pounds of iron/cubic yard and a trace of chromite. Samples of auger holes of about 1.2 m length reported by Foley and others (1995, figure 15, Appendix A) contained gold, titanium, and zircon. A head split of sample number 281 contained 0.056 grams/ton of gold; a spiral concentrate of the same sample contained 2.01 percent titanium and 535 ppm zirconium. A spiral concentrate derived from sample number 283 contained gold; it also contained 1.89 percent titanium and 526 ppm zirconium.
Indication of production Undetermined

Additional comments

The deposit is in Tongass National Forest. Lands immediately offshore belong to the State of Alaska.

References