| Basis for focus area |
High sulfidation Au-Ag deposits with large areas of locally alunite-rich advanced argillic alteration; area of stockwork quartz-sericite-pyrite veins is part of an inferred gold-rich porphyry system (Sillitoe and Lorson, 1994); much of mined ore contained high Sn contents (John and others, 1991); 1 km buffer around mapped alteration and ASTER phyllic and argillic alteration (Mars, 2013). |
| Identified resources |
Historical production of gold, mercury, and silver. |
| Production |
Between 1986-1994, 24.3 million t of ore, 1.626 million oz Au, 23.99 million oz Ag, as well as significant Hg from high sulfidation gold-silver deposits. |
| Status |
Past mining. |
| Estimated resources |
Reserves in 1996 remaining at the Ketchup Flats deposit were 5 million tons of ore grading 0.022 opt Au and 0.2 opt Ag. |
| Geologic maps |
John and Kelleher (1987), scale 1:24,000; John (1988), scale 1:24,000; Sillitoe and Lorson (1994), scale ~1:40,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. ASTER remote sensing by Mars (2013). |
| Favorable rocks and structures |
Early Miocene intermediate dome field emplaced into late Oligocene-early Miocene silicic tuffs and intermediate lava flows. |
| Deposits |
Paradise Peak (includes Paradise Peak, Ketchup Flats, Ketchup Hill, Ketchup Knob, and County Line) (MRDS dep_id: 10310352 ), Nody prospect (MRDS dep_id; 10098380-a small Hg deposit overlying Paradise Peak). |
| Evidence from mineral occurrences |
MRDS; John and others (1991); Sillitoe and Lorson (1994). |
| Geochemical evidence |
John and others (1991); Sillitoe and Lorson (1994); Ga enrichment in alunitic alteration in Rytuba and others (2003). |
| Geophysical evidence |
Remote sensing data in Rockwell and Hofstra (2008) and Mars (2013). |
| Evidence from other sources |
None. |
| Comments |
Alunitic and silicic alteration and precious metal mineralization appear to be controlled by throughgoing northwest-trending high-angle fractures and faults, which are perhaps related to pre-Basin and Range extension. See Cheong and others (2000). |
| Cover thickness and description |
Surface exposure. |
| Authors |
David A. John. |
| New data needs |
Geologic mapping, geophysics. |
| Geologic mapping and modeling needs |
Updated geologic mapping. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys. |
| Digital elevation data needs |
Lidar in progress (GeoDAWN). |
