Main commodities | Cu; Mo |
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Other commodities | Au; Zn |
Ore minerals | arsenopyrite; chalcopyrite; molybdenite; sphalerite |
Gangue minerals | clay; epidote; fluorite; quartz |
Quadrangle map, 1:250,000-scale | TK |
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Quadrangle map, 1:63,360-scale | D-5 |
Latitude | 62.8777 |
Longitude | -149.2943 |
Nearby scientific data | Find additional scientific data near this location |
Location and accuracy | Three mineralized sites are on or near Treasure Creek, a small informally named, east tributary of Portage Creek. The mouth of Treasure Creek is 4 miles upstream from the mouth of Portage Creek on the Susitna River The sites are within a mile of each other in an area centered in the NE1/4SE1/4 sec. 8, T. 32 N., R. 1 E., Seward Meridian. This is locality 9 of Csejtey and Miller, (1978). |
Geologic descriptionThe three mineralized sites of the prospect have disseminated arsenopyrite, chalcopyrite, molybdenite, and sphalerite, quartz, fluorite, and epidote in a silicified and sheared Tertiary granite stock, and in argillite and metagraywacke intruded by the granite (Richter, 1963). There is local intense argillic alteration and limonite staining that extends irregularly up to 300 feet into the granite from a fault. The argillite and metagraywacke are part of an extensive Lower Cretaceous flysch unit. The stock is part of the lower Tertiary McKinley plutonic sequence. Samples of an arsenopyrite-rich boulder found on the surface contain 0.18 ounce of gold per ton, 2-3 percent zinc, 0.1-0.5 percent copper, and 0.1-0.5 percent molybdenum (Richter, 1963). Rock samples from one of the sites contain contain up to 1.0 percent molybdenum, 2.65 percent zinc, and 1.7 ounces of silver per ton (Kurtak and others, 1992). This prospect was explored by minor surface workings and shallow drilling. A caved adit is 500 feet south of the creek, near the east boundary of section 8 at an elevation of about 1,400 feet. Silver Dome Mining Company staked the Molly 1 to 18 claims, the Caribou 1 to 59 claims, and the Cheechako Moose 1 to 21 claims. | |
Geologic map unit | (-149.296562433004, 62.877219429238) |
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Mineral deposit model | Porphyry Cu-Mo (Cox and Singer, 1986; model 21a) |
Mineral deposit model number | 21a |
Age of mineralization | In Early Tertiary rocks. |
Alteration of deposit | Silicification, argillic and epidote alteration, with iron staining. |
Workings or exploration | This prospect was explored by minor surface workings and shallow drilling. A caved adit is 500 feet south of the creek, near the east boundary of section 8 at an elevation of about 1,400 feet. Rock sampling by the U.S. Geological Survey and U.S. Bureau of Mines (Richter, 1963; Kurtak and others, 1992). Silver Dome Mining Company staked the Molly 1 to 18 claims, the Caribou 1 to 59 claims, and the Cheechako Moose 1 to 21 claims. |
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Indication of production | None |
Additional commentsMAS/MILS number 20760005. |
MRDS Number | A012173 |
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References | |
Reporters | R.K. Rogers (U. S. Geological Survey contractor) |
Last report date | 9/26/2002 |