Unnamed (in Table Bay) (ARDF #PA039) Cu, Fe, Mo, W

Unnamed (in Table Bay)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities	Cu; Fe; Mo; W
Ore minerals	chalcopyrite; pyrite; pyrrhotite
Gangue minerals	calcite; epidote; garnet; quartz

Geographic location

Quadrangle map, 1:250,000-scale	PA
Quadrangle map, 1:63,360-scale	A-1
Latitude	56.13541
Longitude	-134.252
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This occurrence was first identified by Still and others (2002) and the location is accurate. It is about 0.2 mile south-southeast of triangulation station 'Bel' near the south end of the mouth of Table Bay. The occurrence is about 0.6 mile southwest of the northeast corner of section 22, T. 66 S., R. 72 E.

Geologic setting

Geologic description This occurrence was discovered by Still and others (2002). It is associated with the periphery of a small intrusion less than a mile in diameter of hornblende quartz monzonite of Cretaceous age (Brew and others, 1984). The body intrudes rocks of the Bay of Pillars Formation of Silurian age which here consists of graywacke with mudstone and minor limestone. The deposit is associated with epidote-quartz-skarn that is mineralized over an area about 200 by 500 feet. The mineralization consists of irregular masses of pyrrhotite and pyrite with minor chalcopyrite scattered through the skarn and in irregular quartz-calcite veinlets. The skarn generally contains less than 1 percent sulfides and the richest samples collected by Still and others (2002) contained 2,000 parts per million (ppm) tungsten, 3,082 ppm copper, and 112 ppm molybdenum.
Geologic map unit	(-134.253735169795, 56.1350236158919)
Mineral deposit model	Tungsten skarn (Cox and Singer, 1986; model 14a).
Mineral deposit model number	14a
Age of mineralization	Skarn developed during intrusion of Cretaceous quartz monzonite.
Alteration of deposit	The deposit is in an epidote-quartz-garnet skarn.

Production and reserves

Workings or exploration	Only sampling by government geologists.
Indication of production	None
Reserve estimates	None.
Additional comments MAS number: 0021160070.

References

References Brew, D.A., Ovenshine, A.T., Karl, S.M., and Hunt, S.J., 1984, Preliminary reconnaissance geologic map of the Petersburg and parts of the Port Alexander and Sumdum 1:250,000 quadrangles, southeastern Alaska: U.S. Geological Survey Open-File Report 84-405, 43 p., 2 sheets, scale 1:250,000. 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	Donald J. Grybeck (U.S. Geological Survey)
Last report date	2-Jan-05