Unnamed (near Mt. Young) (ARDF #JU020) Zn

Unnamed (near Mt. Young)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Zn
Other commodities	Ag; Ba; Cr; Cu; Mo; Pb
Ore minerals	barite; chalcopyrite; pyrite
Gangue minerals	quartz

Geographic location

Quadrangle map, 1:250,000-scale	JU
Quadrangle map, 1:63,360-scale	D-5
Latitude	58.8876
Longitude	-135.5773
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.

Geologic setting

Geologic description 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.

Production and reserves

Workings or exploration	Apparently only surface sampling.
Indication of production	None

References

MRDS Number	A012104
References 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. Wells, D.E., Pittman, T.L., Brew, D.A. and Douglass, S.L., 1986, Map and description of the mineral deposits in the Juneau, Taku River, Atlin, and part of the Skagway quadrangles, Alaska: U.S. Geological Survey Open-File Report 85-717, 332 p., 1 sheet, scale 1:250,000.
Reporters	J.C. Barnett and L.D. Miller (Juneau, Alaska )
Last report date	12/15/2001