|Quadrangle map, 1:250,000-scale||UK|
|Quadrangle map, 1:63,360-scale||B-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This site is located on the west coast of Umnak Island along the southeast shore of Cemetery Cove (Christie, 1974, anomaly 34). The location is accurate to within 1 1/2 miles.|
Geologic descriptionAt this site a color anomaly, measuring approximately 11,000 by 1000 feet, is present along the shore and represents the weathering of a very well-developed quartz stockwork in a dacitic or rhyolitic flow (Christie, 1974). These rocks have been mapped as Tertiary to Quaternary in age (Byers, 1959). The stockwork consists of thin, generally barren, vuggy quartz veinlets in highly pyritized and silicified wall rock. The veinlets are continuous but appear to be randomly oriented. The stockwork itself contains 0 to 10 percent pyrite and a trace of chalcopyrite. Metal values in 20 samples of quartz veins and pyritized wall rock contained up to 150 ppm copper, 21 ppm molybdenum, 0.03 ppm gold, 1.6 ppm silver, and 68 ppm zinc (Christie 1974). Forty-four samples collected at a later date contained up to 1130 ppm arsenic, 491 ppb gold, 2.8 ppm silver, 260 ppb mercury, and 94 ppm molybdenum (Randolph and Ellis, 1989).
|Geologic map unit||(-168.401991047367, 53.2990834797937)|
|Mineral deposit model||Quartz stockwork with minor copper, molybdenum, zinc, and precious metal values.|
|Age of mineralization||Tertiary.|
|Alteration of deposit||The alteration consists of propylitization, along with localized silicification and pyritization.|
|Workings or exploration||
Brief reconnaissance mapping and fairly extensive rock-chip sampling were done by the Aleut-Quintana-Duval JV in 1974. Twenty rock chip samples yielded up to 150 ppm copper, 21 ppm molybdenum, 150 ppm copper, 0.03 ppm gold, 1.6 ppm silver and 68 ppm zinc. Most higher gold values came from samples of quartz veinlets (Christie, 1974).Forty-four samples collected at a later date contained up to 1130 ppm arsenic, 491 ppb gold, 260 ppb mercury, 94 ppm molybdenum, and 2.8 ppm silver (Randolph and Ellis, 1989).
|Indication of production||None|
Additional commentsThis site is located on lands selected by the the Aleut Native Corporation.
Byers, F.M., Jr., 1959, Geology of Umnak and Bogoslof Islands, Aleutian Islands, Alaska: U.S. Geological Survey Bulletin 1028-L, p. 267-369, 3 sheets, scales 1:63,360, 1:96,000, 1:300,000.
Christie, 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.)
Randolph, D.B., and Ellis, W.T., 1989, Unalaska project, 1989 final report: Battle Mountain Exploration Company, Alaska District, 41 p., 5 appendices, 11 plates, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)
|Reporters||S.H. Pilcher (Anchorage)|
|Last report date||1/27/2000|