Unnamed (west of the terminus of Nelson Glacier)

Occurrence, Probably inactive

Commodities and mineralogy

Main commodities Ag; As; Cu; Pb; Zn
Ore minerals chalcopyrite; galena; pyrite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale BC
Quadrangle map, 1:63,360-scale B-6
Latitude 56.4788
Longitude -131.999
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is just west of the terminus of the Nelson Glacier near the center of section 21, T. 62 S. R. 86 E., of the Copper River Meridian. The location is accurate.

Geologic setting

Geologic description

This occurrence is in an area that was covered by a large blocks of claims that were variously held from 1965 to 1981 by Bunker Hill Mining Company, Humble Oil and Refining Company, El Paso Natural Gas Company, and AMAX Exploration (Still and others, 2002). There apparently was no exploration of these particular occurrences by these companies beyond areal mapping and sampling, or at least there is no notable record of any.
The country rocks in the area of the prospects include Tertiary to Cretaceous biotite schist, biotite-garnet-quartz schist, quartzofeldspathic gneiss, and minor marble and calc-silicate gneiss metamorphosed from Mesozoic to Paleozoic protoliths (George and Wyckoff, 1973; Brew, 1997). The metamorphic rocks near the prospect are cut by several large Tertiary felsic dikes and sills that have been dated nearby at about 16.2 Ma (see PE043), and by a large Cretaceous tonalite pluton that intrudes the metamorphic section just to the east.
Still and others (2002) briefly examined the ridge west of the terminus of the Nelson Glacier and identified a 2-foot-wide vuggy, silicified zone that cuts gneiss. The silicified zone extends for about 80 feet and locally contains pyrite, chalcopyrite, galena, and sphalerite. A 0.2-foot-thick chip sample across what appeared to be the most mineralized section of the zone contained 4.39 ounces of silver per ton, 2.70 percent lead, 9, 577 parts per million (ppm) zinc, and 8.63 ppm arsenic. (The mineralization is similar to or an extension of the mineralization in the prospect about 0.3 mile to the northeast across the terminus of the Nelson Glacier (BC001)).
Geologic map unit (-132.000682082886, 56.4784658220279)
Mineral deposit model Vuggy silicified zone in gneiss.
Age of mineralization Probably related to a nearby 16.2 Ma biotite granite as are other deposits in the Groundhog Basin area.

Production and reserves

Workings or exploration This occurrence is on a large block of claims that were variously held from 1965 to 1981 by Bunker Hill Mining Company, Humble Oil and Refining Company, El Paso Natural Gas Company, and AMAX Exploration (Still and others, 2002). There apparently was no exploration of these occurrences by these companies beyond areal mapping and sampling. Still and others (2002) examined these occurrences as part of a regional mineral assessment by 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