Casadepaga River

Prospect, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold
Gangue minerals garnet; magnetite

Geographic location

Quadrangle map, 1:250,000-scale SO
Quadrangle map, 1:63,360-scale D-5
Latitude 64.882
Longitude -164.221
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Casadepaga River is a major west tributary to the Niukluk River. This locality is near the mouth of Dry Creek (Gulch). It is at an elevation of about 210 feet, and 1.3 miles above the mouth of Big Four Creek (SO066). It is locality 55 of Cobb (1972, MF 445; 1978, OF 78-181).

Geologic setting

Geologic description

The Casadepaga River is a major west tributary to the Niukluk River. The first 11 miles upstream from the mouth varies from 170 to 270 feet in elevation. The next 8 to 9 miles upstream gains another 150 feet of elevation. The lower 11 miles of the river has a pronouced floodplain over most of its length but in general this river is incised into benches and terraces that have surfaces 30 to 150 feet higher than the present drainage. Gold colors are commonly present in the bench gravels and mining has commonly taken place where tributaries cross the benches and rework these gravels (Collier and others, 1908). Heavy mineral concentrates from various parts of the drainage commonly contain garnet and magnetite. In general, bedrock was not exposed by early mining operations along the lower part of this river. As noted by Smith (1910), the depth to bedrock is known to vary from as much as 57 feet at the mouth of Penelope Creek (SO079) to 17 feet a half mile above the mouth of Big Four Creek (SO066). Smith (1910) noted that prospecting of bench gravels took place at this locality, the mouth of Dry Creek or Gulch. The bench gravels were at least 10 feet thick, contained gold colors from grassroots down, and values to about 1/4 ounce of gold per cubic yard were locally present. Bedrock was not encountered and the bench gravels, in general more muddy than elsewhere along the river, may be up to 50 feet thick (Smith, 1910).
Geologic map unit (-164.223619265956, 64.8812611950485)
Mineral deposit model Placer Au-PGE (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary; the numerous incised terraces along the Casadepaga River indicate that more than one cycle of erosion and deposition has developed placer deposits in the area. The low elevations between 170 and 270 feet along the first 11 miles of the river, suggest that Quaternary sea level fluctuations could have influenced placer development.

Production and reserves

Workings or exploration Prospect pits to 10 feet deep were dug here before 1907.
Indication of production Undetermined