| Basis for focus area |
Predominantly a precious metal district, but the focus area includes minor shows of zinc and traces of tellurium and antimony (McLemore, Goff and McIntosh, 2014; McLemore, 2013a). Area encompasses Oligocene-Miocene alkaline (and subalkaline) intrusions that are genetically associated with breccias, fissures, and small disseminated ore bodies (Segerstrom and others, 1979). Outline of focus area from McLemore (2013a, 2017). |
| Identified resources |
Identified resources for gold; historical production of copper, gold, lead, silver, and zinc. |
| Production |
15,000 ounces Au; see McLemore (2017). |
| Status |
Past mining; current minor prospecting for Au placers. |
| Estimated resources |
190,000 ounces Au (Fulp and Woodward, 1991). |
| Geologic maps |
Cikoski and others (2011), scale 1:24,000; Goff and others (2011), scale 1:24,000; Rawling (2004; 2010), scale 1:24,000; Thompson (1973), scale 1:63,360. |
| Geophysical data |
Inadequate Rank 5 aeroradiometric and rank 4 aeromagnetic coverage. |
| Favorable rocks and structures |
Magmatic-hydrothermal breccias, fissures, and veins associated with Oligocene-Miocene alkalic rocks. |
| Deposits |
Mudpuppy-Waterdog prospect (MRDS dep_id: 10015010), American mine (MRDS dep_id: 10014015), Helen Rae (MRDS dep_id: 10087885), Crow (MRDS dep_id: 10014062), Maud (MRDS dep_id: 10014068). |
| Evidence from mineral occurrences |
MRDS; Fulp and Woodward (1991). |
| Geochemical evidence |
Tellurium in soil in a zone of phyllic alteration ranges from 1 to 7.1 ppm (Fulp and Woodward, 1991). Mineralized rocks contain as much as 10,000 ppm Sb, 108,200 ppm Zn, and 447 ppm As (McLemore, Goff and McIntosh, 2014). Tetradymite reported at one site (Segerstrom and others, 1979; McLemore, 2013a). |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Regional patterns of porphyry related mineralization. |
| Comments |
Much of the focus area is a wilderness area. |
| Cover thickness and description |
No significant cover. |
| Authors |
Joshua M. Rosera, Virginia T. McLemore. |
| New data needs |
Detailed alteration mapping, chemistry, mineralogy. |
| Geologic mapping and modeling needs |
Alteration mapping. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and radiometric surveys. |
| Digital elevation data needs |
Lidar complete in southern half of focus area; in progress in the northern half. |
