|Quadrangle map, 1:250,000-scale||NB|
|Quadrangle map, 1:63,360-scale||D-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is on a ridge between two unnamed west tributaries of Porcupine Creek. It is close to a saddle at an elevation of about 4,700 feet, about 1.1 miles west of the Eagle trail, in the SW1/4 of section 19, T. 12 N., R. 8 E. of the Copper River Meridian. This is locality 1 of Richter and others (1975). It is located to within several hundred feet. Cobb and Richter (1980) included this occurrence under the name 'Indian Pass Lake'.|
Geologic descriptionDisseminated pyrite and small quartz-pyrite veins occur in a small hornblende diorite stock that intrudes late Paleozoic andesitic rocks of the Tetelna Volcanics (Richter, 1966, 1976; Richter and others, 1975). A sample of hornblende diorite with minor disseminated pyrite from this locality contained 0.3 part per million gold (sample R60, Richter and Matson, 1968). Plutonic rocks in this area are part of a Pennsylvanian magmatic suite that varies from gabbro to granite and has U-Pb zircon ages between 290 and 320 Ma (Richter, Lanphere, and Matson, 1975; Miller, 1994, p. 541-542).
|Geologic map unit||(-143.990193647817, 62.806112141071)|
|Mineral deposit model||Polymetallic veins and/or porphyry Cu-Au (Cox and Singer, 1986; models 22c and 20c)|
|Mineral deposit model number||22c; 20c|
|Age of mineralization||Probably Pennsylvanian, the age of plutonic rocks in the area.|
|Alteration of deposit||Oxidation; pyrite-bearing rocks in this area are commonly limonite-stained (Richter, 1966).|
|Indication of production||None|
Cobb, E.H., and Richter, D.H., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Nabesna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-927, 117 p.
Miller, T.P., 1994, Pre-Cenozoic plutonic rocks in mainland Alaska, in Plafker, George, and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol. G-1, p. 535-554.
Richter, D.H., 1966, Geology of the Slana district, southcentral Alaska: Alaska Division of Geological and Geophysical Surveys Geological Report 2l, 54 p., 3 sheets, scale 1:63,360.
Richter, D.H., 1976, Geologic map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-932, 1 sheet, scale 1:250,000.
Richter, D.H., and Matson, N.A., Jr., 1968, Distribution of gold and some base metals in the Slana area, eastern Alaska Range, Alaska: U.S. Geological Survey Circular 593, 20 p.
Richter, D.H., Lanphere, M.A., and Matson, N.A., Jr., 1975, Granite plutonism and metamorphism, eastern Alaska Range, Alaska: Geological Society of American Bulletin, v. 86, p. 819-820.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||11/24/2002|