| Quadrangle map, 1:250,000-scale | MC |
|---|---|
| Quadrangle map, 1:63,360-scale | B-4 |
| Latitude | 61.4016 |
| Longitude | -142.3716 |
| Nearby scientific data | Find additional scientific data near this location |
| Location and accuracy | This prospect in the cirque at the head of Radovan Gulch (MacKevett and Smith, 1972). It is at an elevation of about 5,200 feet, 3,000 feet southeast of elevation 7850 and 1,500 feet south of the center of section 28, T. 5 S., R. 17 E. of the Copper River Meridian. This is locality 65 of MacKevett (1976) and it is accurately located. Cobb and MacKevett (1980) included the prospect under the name 'Radovan'. |
Geologic descriptionThe deposit at this prospect consists of a brecciated fault zone that contains sporadically distributed chalcocite, chalcopyrite, pyrite, and marcasite (Miller, 1946). Realgar, orpiment, and stibnite are also reported to be localized in the fault zone but their relation to the copper mineralization is not clear (Sainsbury, 1951). The fault zone strikes N 25 E, dips 70-75 SE and has a vertical displacement of 1000 feet; it is the same fault zone as the one at the Radovan Greenstone prospect to the north (MC157). The fault is a 100-foot-wide, shattered zone that includes limonite-stained altered zones, gouge, and broken and recemented colloform bands of calcite, dolomite, and chalcedony. Quartz and epidote are also gangue minerals in the fault zone. In one outcrop, veins of chalcocite, 1- to 6-inches wide, occur over a surface area of 50 square feet (Sainsbury, 1951). The fault zone displaces the contact between the Triassic Nikolai Greenstone and the overlying Triassic Chitistone Limestone; the mineralization is along the part of the fault that places greenstone against limestone (MacKevett and Smith, 1972). The deposit has been explored by surface trenches and 2 short adits. Copper mineralization is common in Nikolai Greenstone and overlying Chitistone Limestone. It is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997). | |
| Geologic map unit | (-142.373653276012, 61.4011773375617) |
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| Mineral deposit model | Basaltic Cu (Cox and Singer, 1986; model 23) and/or Kennecott-type copper deposit (after MacKevett and others, 1997) |
| Mineral deposit model number | 23? |
| Age of mineralization | Cretaceous? Copper mineralization is common in Nikolai Greenstone and overlying Chitistone Limestone. It is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic to Early Cretaceous (MacKevett and others, 1997). |
| Alteration of deposit | Oxidation is evidenced by limonite staining. Silicification and epidotization are locally present in the fault zone. |
| Workings or exploration | The deposit has been explored by surface trenches and 2 short adits. |
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| Indication of production | Yes; small |
Additional commentsThe locality is in the Wrangell-Saint Elias National Park and Preserve. | |
| MRDS Number | A011703 |
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ReferencesMacKevett, E.M., Jr., Cox, D.P., Potter, R.W., III, and Silberman, M.L., 1997, Kennecott-type deposits in the Wrangell Mountains, Alaska--High-grade copper ores near a basalt-limestone contact, in Goldfarb, R.J., and Miller, L.D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 66-89.
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| Reporters | Travis L. Hudson (Applied Geology, Inc.) |
| Last report date | 1/12/2003 |