Lode mineralization is associated with Mesozoic felsic plutons (granite, granodiorite) and volcanic rocks intruded in Precambrian and Phanerozoic age rocks in Alaska. The precious metal has also been found throughout much of Alaska except vast uninhabitable swamps of the Yukon Flats and on the North Slope of the Arctic between the Brooks Range and the Beaufort Sea. In the vast central uplands and plains and in the Pacific Mountains to the south, numerous gold, silver and massive sulfide deposits are found. The central uplands and plains between the Brooks Range to the north and the Pacific Mountains to the south is a vast region of alluvial lowlands and eroded plateaus known for placer gold such as Seward, Koyukuk, Yukon and Kuskokwim uplands and peninsulas that overlook the broad flat plains of the Yukon River.
|The Kennecott mine, Nizina district, Alaska|
Chichagof mining district
|Cinnabar (red) from Decourcy, Alaska, photo|
by the author.
Gold was discovered in the Yentna District (aka Cache Creek District) of the upper Susitna Valley in 1898. Placer mining was reported in the Cache Creek drainage of the Dutch Hills by 1906. Quaternary glaciofluvial deposits, alluvial deposits, and Tertiary conglomeratic white quartz-breccia units were mined in the Dutch Hills. About 200,000 ounces of gold has been produced from the placer deposits.
Willow Creek Mining District
|Nuggets nuggets recovered from Julian|
Creek, 1988, photo by the author.
|Pristine gold nugget attached to rounded pebble, Snow Gulch,|
Alaska. Such nuggets provide evidence of regeneration of gold
possibly related to organic deposition (Paul Graff, personal
communication, 1988 (photo by the author).
Interior of Alaska (north of Yukon River)
Placer gold was discovered on Klery Creek in 1909 within the Kiana district. More than 40,000 ounces, for gold was mined from this area from placers in tributaries of Squirrel River. Mining has been nearly continuous in this area since discovery. Nephrite jade also occurs in this area.
In 1898, placer and lode gold were discovered on several of the Kobuk River's tributaries. The gold strike (by some accounts was a fraud) attracted nearly 2,000 people to Alaska, though only 800 actually stayed to find gold. Although mining has continued to take place in this area, little gold has been discovered.
All of the 15,000 ounces of gold recovered came from streams draining the Cosmos Hills, a low range along the Kobuk Valley. Gold was discovered on Dahl Creek in 1898, which was the major producer. Copper, chromium, cadmium, and silver, were also recovered with the gold.
The district, located about 40 miles east of Nome, produced over a million ounces of gold.
|Dr. Paul Graff looks at abandoned monitor in Alaska, 1988|
This district, which produced about 576,000 ounces, includes placer mines at Manley and Eureka.
Nearly 200,000 ounces of gold was recovered from placer mines in the district.
Ruby-Poorman mining district
Ruby-Poorman District lies south of the Yukon River and is attributed with nearly a half million ounces of gold, all from placer mines. The largest gold nugget found in Alaska (294.1-troy ounces) was recovered from Swift Creek in 1998. The placers are mostly deeply buried, and most were originally worked with shafts and drifts. Dozens of creeks in the district were mined, many more bear gold prospects. Cassiterite, platinum, scheelite, allanite, and native bismuth have been recovered along with gold from placer mines in the district.