Main commodities | Cu |
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Other commodities | Ag |
Ore minerals | chalcopyrite; pyrite |
Gangue minerals | magnetite |
Quadrangle map, 1:250,000-scale | UN |
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Quadrangle map, 1:63,360-scale | C-1 |
Latitude | 53.75 |
Longitude | -166.1667 |
Nearby scientific data | Find additional scientific data near this location |
Location and accuracy | East side of Sedanka Island. Anomaly no. 25 of Christie (1974). |
Geologic descriptionColor anomaly 6,000 ft (1800 m) by 2,000 ft (600 m) occurs in volcanic rocks of the Unalaska Formation (see Drewes and others, 1961). In the east half of the area, scattered, intensely altered zones of pyrite-chlorite +/- epidote are separated by zones of moderate alteration containing minor pyrite and abundant fracture-controlled magnetite and epidote. According to Christie (1974), the only possible intrusive rocks are intensely bleached and contain 3 to 10 percent pyrite. Chalcopyrite is minor and sporadic in occurrence, where present it occurs as fracture fillings and disseminated in both weakly and intensely altered rock. Where chalcopyrite does occur, grade is less than 200 ppm. Fracturing is weak to moderately developed. | |
Geologic map unit | (-166.168609545671, 53.7491577976732) |
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Mineral deposit model | Copper porphyry? |
Mineral deposit model number | 17 |
Age of mineralization | Miocene or younger |
Alteration of deposit | Propylitic alteration having the assemblages pyrite-chlorite +/- epidote and magnetite-epidote +/- chlorite. Christie (1974) reported leaching is weakly developed. Intensely bleached rocks containing up to 10 percent pyrite are locally present. (Possible sericitic alteration?). |
Workings or exploration | Brief reconnaissance mapping and a few soil/silt samples showed low level anomalies, most significant was 1.3 to 1.4 ppm silver. |
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Indication of production | None |
Additional commentsSee UN005, Sedanka, which occurs to the northwest of this occurrence. |
MRDS Number | A106014 |
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ReferencesChristie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps. (Report held by the Aleut Corporation, Anchorage, Alaska.)
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Reporters | Damon Bickerstaff, F.H. Wilson |
Last report date | 5/8/1996 |