Unnamed (at head of Mosman Inlet)

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Ore minerals chalcopyrite; magnetite; pyrite; sphalerite
Gangue minerals calcite; garnet

Geographic location

Quadrangle map, 1:250,000-scale PE
Quadrangle map, 1:63,360-scale A-2
Latitude 56.1453
Longitude -132.5823
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at the head of Mosman Inlet about 0.5 mile southeast of triangulation station 'Moss. It is near the center of section 16, T. 66 S., R. 83 E.

Geologic setting

Geologic description

This occurrence was first reported by Pittman (1962) as a 3-feet-wide calcite vein exposed for about 10 feet on the beach and below the high-tide line. The vein has abundant garnet, chalcopyrite, pyrite, and light colored sphalerite. A sample across the vein contained 9.5 percent zinc, 0.13 percent copper, 0.41 ounce of silver per ton, and traces of gold and lead. Still and others (2002) examined the area but did not find Pittman's vein. They did find a zone of tactite with calcite, garnet, magnetite, calc-silicate minerals, and chalcopyrite. The tactite is 0.1 to 0.7 foot thick and 3 feet long in a cliff near tidewater. Samples across the tactite contained up to 1,482 parts per billion gold, 35.4 parts per million (ppm) silver, 3,635 ppm copper, and 585 ppm zinc. The area is at or near the contact of Tertiary granite with Triassic and Cretaceous greenstone and Mesozoic or Paleozoic metasedimentary and metavolcanic rocks (Karl and others, 1999).
Geologic map unit (-132.583992728949, 56.1449402326673)
Mineral deposit model A calcite vein and/or tactite with silver, gold copper, and zinc minerals.
Alteration of deposit Occurrence at least in part is a contact metamorphic assemblage with sulfides.

Production and reserves

Workings or exploration Apparently only sampling by government engineers and geologists.
Indication of production None

References

References

Pitman, T., 1962, Report of the Mosman Inlet occurrence: Unpublished U.S. Bureau of Mines Report, 6 p. (Copy held by the Bureau of Land Management, Minerals Information Center, Juneau, Alaska).
Still, J.C., Bittenbender, P.E., Bean, K.W., and Gensler, E.G., 2002, Mineral assessment of the Stikine area, central Southeast Alaska: U.S. Bureau of Land Management Technical Report 51, 560 p.
Reporters D.J. Grybeck (Port Ludlow, WA)
Last report date 4/8/2007