|Quadrangle map, 1:250,000-scale||JU|
|Quadrangle map, 1:63,360-scale||D-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is 2 miles north of Mt. Young at an elevation of approximately 2,500 feet. It is in the SE1/4 section 28, T. 34 S., R. 59 E. of the Copper River Meridian. The location is accurate within 1/2 mile. There are several other geologically similar occurrences in the Mt. Young area (JU017, JU025); the locations given by Wells and others (1986) appear to be the most accurate.|
This occurrence consists of short, quartz veins, usually less than 6 inches thick, and numerous altered zones, about 2 feet thick. The altered zones transect metavolcanic rocks, schist, hornfels, slate, and marble. A few zones are localized along the margins of mafic dikes that cut the metamorphic rocks. The altered zones consist mainly of hydrous iron oxides, carbonate minerals, and quartz; minor pyrite, chalcopyrite, barite, and clay minerals are also present (MacKevett and others, 1971). MacKevett and others (1971) also report that the highest analytical metal values were from a sample consisting of sulfides, chiefly pyrite, replacing metavolcanic rocks, and from a sample of altered hornfels. These samples contained 1500 ppm zinc and anomalous silver, chromium, copper, molybdenum, and lead.The rocks in the vicinity of this occurrence consist of deformed and metamorphosed Silurian or Devonian carbonate, clastic and volcanic clastic units that have been intruded by Upper Jurassic and Lower Cretaceous granitic and dioritic rocks (Brew and others, 1992). This occurrence is in a geologically complex area characterized by a variety of metamorphic rocks, small granitic plutons, and mafic dikes (MacKevett and others, 1971).
|Geologic map unit||(-135.579155238676, 58.887256653209)|
|Alteration of deposit||Iron-oxide alteration; clay alteration; hornfelsing.|
|Workings or exploration||Apparently only surface sampling.|
|Indication of production||None|
Brew, D.A., and Ford, A.B., 1985, Preliminary reconnaissance geologic map of the Juneau, Taku River, Atlin, and part of the Skagway 1:250,000 quadrangles, southeastern Alaska: U.S. Geological Survey Open-File Report 85-395, 23 p., 2 sheets, scale 1:250,000.
Brew, D.A., Himmelberg, G.R., Loney, R.A., and Ford, A.B., 1992, Distribution and characteristics of metamorphic belts in the southeastern Alaska part of the North American Cordillera--Metamorphic styles in young and ancient orogenic belts: Journal of Metamorphic Geology, v. 10, no. 3, p. 465-482.
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.
MacKevett, E.M., Jr., Brew, D.A., Hawley, C.C., Huff, L.C., and Smith, J.G., 1971, Mineral resources of Glacier Bay National Monument, Alaska: U.S. Geological Survey Professional Paper 632, 90 p., 12 plates, scale 1:250,000.
|Reporters||J.C. Barnett and L.D. Miller (Juneau, Alaska )|
|Last report date||12/15/2001|