Salmon Bay

Location: Alaska, United States (56.321, -133.170 approx.)

Commodities: rare earth elements

Deposit model: REE-Th bearing veins · Th-REE veins

Geology

Short, irregular, and lenticular veins of radioactive carbonate-hematite crop out along the coast for about 13 km (8 mi). Some veins can be traced for more than 91 m (300 ft) between the low-tide line and forest cover. The veins cut the Salmon Bay greywacke, a thick formation of Silurian age. On average, the veins are 5-8 cm (2-3 in.) wide, though they normal range from less than 2 cm (1 in.) to as much as 0.76 m (2.5 ft). A few veins reach 1.5-3 m (5 to 10 ft) in width. (Long and others (2010)) The predominant minerals in the veins are dolomite-ankerite and alkali feldspar, with lesser amounts of hematite, pyrite, siderite, magnetite, quartz, chalcedony, and chlorite (Houston and others, 1955). Other minerals identified include parisite, bastnasite, muscovite, fluorite, apatite, thorite, zircon, monazite, epidote, topaz, garnet, chalcopyrite, and marcasite. The radioactivity in the veins is caused by thorite and monazite, both of which contain thorium. The fluorcarbonates parisite and bastnasite are found in nonradioactive carbonate-hematite veins, which are also located along the coast and are wider than the radioactive veins. Of the two fluorcarbonates, parisite is more abundant and appears to be a late-stage mineral that fills in small vugs or was deposited along fractures in the host carbonate vein (Houston and others, 1955). (Long and others (2010))

Exploration and site history

• Discovery — Samples from Salmon Bay submitted by John Wandve in May 1950 have an average radioactivity of about 0.01 percent uranium, 1950 (Houston and others (1958))

Record imported from USGS USMIN ver. 4.0 (June 2019). Developments after that date appear on facility records, not here; see the methodology.