Unnamed Occurrence (ARDF - IL028; southeast of Upper Copper Lake), Bristol Bay District, Lake and Peninsula Borough, Alaska, USA
Location: This occurrence is at an elevation of about 1,000 feet on the north slope of the divide between Upper Copper Lake and Boot Lake. It is about in the center of the S1/2 NE1/4 sec. 7, T. 7 S., R. 28 W., Seward Meridian. The location is accurate within about 0.5 mile. The site is locality 13 of Detterman and Cobb (1972).
Geology: This occurrence is near the contact between granitic plutons of Tertiary and Cretaceous or Tertiary age (Read, 1967; Detterman and Reed, 1980). It consists of pyritized, argillized, and sericitized(?) granitic intrusive rock in a 400-foot-long exposure along a fault-controlled, unnamed northerly-flowing stream. The granitic rocks are cut by a mafic dike. The altered rocks contain disseminated flakes of molybdenite. Copper and molybdenum occur in anomalous concentrations in stream-sediment samples collected below the occurrence (Reed,1967), suggesting that the occurrence also contains chalcopyrite. Reed's rock samples, however, did not detect the gold reported by Detterman and Cobb (1972). The fault that controls the exposure may be a splay of a shear zone extending northeastward through the Meadow Lake valley (Reed, 1967).
Workings: Exploration consists of reconnaissance geologic mapping and rock and stream-sediment sampling. Reed's (1967) stream-sediment samples were anomalous for copper and molybdenum, but his rock samples did not detect the gold reported by Detterman and Cobb (1972).
Age: Probably Tertiary.
Alteration: Pyritization and argillic and sericitic(?) alteration.
Commodities (Major) - Au?, Mo; (Minor) - Cu?
Development Status: None
Deposit Model: Porphyry Cu-Mo (Cox and Singer, 1986; model 21a).
| Chalcopyrite ?|| Molybdenite|| Pyrite|
3 entries listed. 3 valid minerals.
The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
Detterman, R.L., and Cobb, E.H., 1972, Metallic mineral resources map of the Iliamna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-364, 1 sheet, scale 1:250,000. Detterman, R.L., and Reed, B.L., 1980, Stratigraphy, structure, and economic geology of the Iliamna quadrangle, Alaska: U.S. Geological Survey Bulletin 1368-B, 86 p. Reed, B.L., 1967, Results of stream sediment sampling and bedrock analyses in the eastern part of the Iliamna quadrangle, and at Kasna Creek, Lake Clark quadrangle, Alaska: U.S. Geological Survey Open-File Report 272, 18 p.
This page is currently not sponsored. To sponsor this page click here.
|Fade toolbar when not in focus||Fix toolbar to bottom of page|
|Hide Social Media Links|
|Slideshow frame delay||seconds|
Locality Updated: Wheal Coates, St Agnes, St Agnes District, Cornwall, England, UKFrom David Ifold, 19th Jun 2013 22:44:10