|Quadrangle map, 1:250,000-scale||MF|
|Quadrangle map, 1:63,360-scale||D-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The general location is near sealevel on the far southeastern point of Gilbert Peninsula north of Blue Mouse Cove. The exact location is uncertain but may instead be about 0.25 mile northwest of the coordinate position, also near sea level. The location is number 37 of Cobb (1972).|
The area is underlain by granodiorite and quartz diorite of Cretaceous age, separated from other granite by a strong fault of northwest strike about 0.5 mile west of the occurrence (Brew and others, 1978, pl. 1A). Mineralization occurs in steep faults and shear zones that strike east-northeast strike and locally contain andesite dikes. MacKevett and others (1971, table 9) reported quartz-calcite veins as much as 1.5 feet thick within a 12-foot-thick shear zone. A 2-foot sample contained 1 ppm silver, 200 ppm copper, 300 ppm lead, and 700 ppm zinc. Bureau of Mines samples of a second zone contained as much as 7 ppm silver, 680 ppm zinc, 220 ppm lead and 3000 ppm arsenic (Kimball and others, 1978, p. C248-249). Two or more vein zones are inferred by Kimball and others (1978); the one they sampled is at least 1000-feet long.
The vein zone was at least 1000 feet long.The presence of weak lead-zinc values, and anomalous amounts of silver in quartz-calcite vein, suggests that the veins are distal structures related, generally, to Cretaceous or younger intrusive activity.
|Geologic map unit||(-136.490849259209, 58.7966100153944)|
|Mineral deposit model||Low-sulfide quartz-calcite veins.|
|Age of mineralization||Probably Cretaceous.|
|Workings or exploration||There are no workings. A Geological Survey selected 2-foot sample contained 1 ppm silver, 200 ppm copper, 300 ppm lead, and 700 ppm zinc (MacKevett and others (1971, table 9). The sample reported by Kimball and others (1978) from about the same locality contained 3000 ppm arsenic, 7 ppm silver, 220 ppm lead, and 680 ppm zinc. The vein sampled by the Bureau of Mines is projected for more than 1000 feet.|
|Indication of production||None|
Veins are possible distal structures related to Cretaceous or younger magmatism. Because of their strength and type of mineralization, they deserve more work.The site is in Glacier Bay National Park and Preserve.
Brew, D.A., Johnson, B.R., Grybeck, D., Griscom, A., Barnes, D.F., Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources of the Glacier Bay National Monument Wilderness Study Area, Alaska: U.S. Geological Survey Open-File Report 78-494, 670 p., 7 sheets.
Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.
Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources, in Brew, D. A., and others, Mineral resources of the Glacier Bay National Monument wilderness study area, Alaska: U.S. Geological Survey Open-File Report 78-494, p. C1-C375.
|Reporters||C.C. Hawley (Hawley Resource Group)|
|Last report date||4/13/1999|