Main commodities | Cu |
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Ore minerals | chalcopyrite; malachite; pyrite |
Gangue minerals | quartz |
Quadrangle map, 1:250,000-scale | GU |
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Quadrangle map, 1:63,360-scale | D-1 |
Latitude | 62.781 |
Longitude | -144.047 |
Nearby scientific data | Find additional scientific data near this location |
Location and accuracy | The J.D. Lyons prospect (Cobb, 1979 [OF 79-1247,p. 18]) is at an elevation of about 4,400 feet on the ridge about 1/4 mile south of the confluence of the two headwater forks of Grubstake Creek . It is in the center of the N1/2, section 35, T. 12 N., R. 7 E., Copper River Meridian. Another geologically similar prospect is at an elevation of about 3,700 feet to the north, but south of Grubstake Creek. The location of these prospects is accurate; they are shown as locality 5 of Richter (1966, figure 5, p. 31), locality 16 of Richter and Matson (1972), and locality 15 of MacKevett and Holloway (1977). |
Geologic descriptionThe Lyons prospect is in hornfelsed, chlorite-hornblende volcanic rocks in the border phase of the Pennsylvanian to Permian, Ahtell pluton (Richter, 1964 and 1966; Richter and Matson, 1968). The hornfels is cut by irregular, discontinuous quartz veins as much as 6 inches thick. The veins and host rock is weakly copper stained (malachite?), and the quartz veins contain small amounts of pyrite and chalcopyrite (Richter 1966, p. 31). | |
Geologic map unit | (-144.049190813269, 62.7806096837275) |
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Mineral deposit model | Polymetallic vein (Cox and Singer, 1986; model 22c) |
Mineral deposit model number | 22c |
Age of mineralization | The mineralization is probably related either to the Pennsylvanian to Permian, Ahtell intrusive or to mid-Jurassic dioritic rocks exposed east of the occurrence. |
Alteration of deposit | Chlorite-hornblende hornfels in altered border phases of the Pennsylvanian to Permian, Ahtell pluton. |
Workings or exploration | The prospect on the ridge at an elevation of about 4,400 feet was developed prior to 1963 by prospect pits and by a 10-foot-long adit (Richter, 1964). |
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Indication of production | None |
MRDS Number | A011846 |
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References | |
Reporters | W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (U.S. Geological Survey) |
Last report date | 12/20/2000 |