|Quadrangle map, 1:250,000-scale||SL|
|Quadrangle map, 1:63,360-scale||C-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Kangik River flows northeast into Aghnaghak Lagoon on the northwest coast of St. Lawrence Island. This site is in hornfels peripheral to the east side of the Sevuokuk pluton, 4.5 miles northeast of Vngyat Point' (Patton and Csejtey, 1971, p. C15). The site, probably located within 0.5 miles, is apparently on the Kangik River. This is locality 2 of Cobb (1972) and Cobb (1980) summarized relevant references under the name 'Kangik R.'.|
A small amount of native copper was found in float of a mafic volcanic hornfels 4 1/2 miles northeast of Vngyat Point (Patton and Cjestey, 1971, p. C15).The hornfels is apparently in the east contact zone of the Sevuokuk pluton. The Sevuokuk pluton is an elongate and composite intrusion that makes up the western coastal headlands of St. Lawrence Island (Patton and Csejtey, 1980). It includes biotite hornblende quartz monzonite and biotite quartz monzonite phases (Csejtey, Patton, and Miller, 1971). The copper-bearing hornfels occurrence is apparently in the contact zone of a biotite hornblende quartz monzonite phase where it intrudes a Cretaceous volcanic assemblage of diverse lithologies and compositions. One K/Ar age determination for the Sevuokuk pluton gave an age of 108 +/- 3.2 Ma (Patton and Csejtey, 1980).
|Geologic map unit||(-171.722794213374, 63.5690695099313)|
|Mineral deposit model||Copper-bearing replacements in hornfels.|
|Age of mineralization||Mid-Cretaceous, the age of the Sevuokuk pluton (108 +/- 3.2 Ma; Patton and Csejtey, 1980)|
|Alteration of deposit||The Cretaceous volcanic assemblage is thermally metamorphosed to hornblende hornfels and albite-epidote hornfels facies where it is in contact with granitic rocks but elsewhere it is commonly propylitically altered (Patton and Csejtey, 1980).|
|Workings or exploration||None|
|Indication of production||None|
Cobb, E.H., 1972, Metallic mineral resources map of the Saint Lawrence quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-465, 1 sheet, scale 1:250,000.
Cobb, E.H., 1980, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in fifteen quadrangles in southwestern and west-central Alaska: U.S. Geological Survey Open-File Report 80-909, 103 p.
Csejtey, Bela, Jr., Patton, W.W., Jr., and Miller, T.P., 1971, Cretaceous plutonic rocks of St. Lawrence Island, Alaska, a preliminary report: U.S. Geological Survey Professional Paper 750-D, p. D68-D76.
Patton, W.W., Jr., and Csejtey, Bela, Jr., 1971, Preliminary geologic investigations of western St. Lawrence Island, Alaska: U.S. Geological Survey Professional Paper 684-C, p. C1-C15.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||9/10/1998|