Unnamed (Near Mt. Lewis Cass)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Mo
Ore minerals chalcopyrite; magnetite; molybdenite; pyrite; pyrrhotite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale BC
Quadrangle map, 1:63,360-scale B-4
Latitude 56.3895
Longitude -131.1119
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is about 1.5 miles southwest of Mt. Lewis Cass; the mineralization appears to extend from about 2,400 to 4,100 feet in elevation and was sampled in outcrop at about 2,500 feet. It is about 0.2 mile southeast of the center of section 19, T 63 S., R. 92 E., of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

The Mount Lewis Cass occurrence was discovered by Still and others (2002). The mineralization is near the contact of Eocene granodiorite and Mesozoic and/or Paleozoic metasedimentary and metavolcanic rocks and marble. The granodiorite contains molybdenite in narrow quartz stringers, in knots, and as disseminations. Several samples contained 1,240 and 1,558 parts per million (ppm) molybdenum. Iron-stained silicified metasedimentary and metavolcanic rocks in float on the south side of the valley contain pyrrhotite, pyrite, and chalcopyrite. Chalcopyrite-bearing samples contained 1.832 ppm to 1.35 percent copper, 289 parts per billion gold, and 17.6 ppm silver.
Geologic map unit (-131.113607048471, 56.3891527979419)
Age of mineralization At least some is Eocene or younger based on the age of the granodiorite host rock.
Alteration of deposit Silicification.

Production and reserves

Workings or exploration Discovered by Still and others (2002) during a regional mineral assessment for the Bureau of Land Management.
Indication of production None

References

References

Still, J.C., Bittenbender, P.E., Bean, K.W., and Gensler, E.G., 2002, Mineral assessment of the Stikine area, central southeast Alaska: Bureau of Land Management Technical Report 51, 560 p.
Reporters D.J. Grybeck (Port Ludlow, WA)
Last report date 3/4/2008