Casey Glacier Sphalerite (ARDF #BC085) Pb, Zn

Casey Glacier Sphalerite

Occurrence, Undetermined

Commodities and mineralogy

Main commodities	Pb; Zn
Other commodities	Ag; Au; Cu
Ore minerals	chalcopyrite; galena; pyrite; sphalerite
Gangue minerals	calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale	BC
Quadrangle map, 1:63,360-scale	A-1
Latitude	56.052
Longitude	-130.203
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	The Casey Glacier Sphalerite occurrence consists of mineralized boulders of float scattered in an area of about a quarter of a square mile (Maas, 1995, p. 233, 235). The occurrence is in the northeast corner of Section 23 between elevations of about 3500 and 4100 feet, on a north-facing mountainside south of the West Fork of Texas Creek. It is about 2.0 miles east of Texas Lake. The above coordinates are for the approximate center of the area of float boulders. The location is accurate to within about a quarter of a mile.

Geologic setting

Geologic description The country rocks in the area of this occurrence are pelitic metasedimentary and subordinate andesitic metavolcanic strata of the Jurassic or older Mesozoic Hazelton Group, which is underlain and locally intruded by the Triassic Texas Creek Granodiorite; and the Eocene Hyder Quartz Monzonite, which intrudes the Hazelton and Texas Creek rocks (Smith, 1977; Koch, 1996). Maas and others (1995, p. 235, 246) describe the occurrence as mineralized float boulders of brecciated Hazelton andesite containing massive bands and veinlets of sphalerite, galena, and minor (?) pyrite and chalcopyrite. The sulfides carry silver and a trace of gold. Intense silica and carbonate alteration has accompanied brecciation and mineralization. Lead-isotope studies of galena from this occurrence (Maas and others, p. 235) indicate that the mineralization is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993).
Geologic map unit	(-130.204705183978, 56.051693584795)
Mineral deposit model	Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number	22c
Age of mineralization	Lead-isotope studies of galena from this occurrence (Maas and others, 1995, p. 235) indicate that the mineralization is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993).
Alteration of deposit	Intense silica and carbonate alteration of brecciated andesite hostrock.

Production and reserves

Indication of production	None
Additional comments Although no outcrop of the banded sulfides was found, the location of the boulder rubblecrop suggests that their source is beneath the icefield at the summit between Ferguson and Casey Glaciers (Maas, 1995, p. 235).

References

References Alldrick, D.J., 1993, Geology and metallogeny of the Stewart mining camp, northwestern British Columbia: British Columbia Department of Mines and Petroleum Resources Bulletin 85, 105 p., 2 plates, scale 1:50,000. Smith, J.G., 1977, Geology of the Ketchikan D-1 and Bradfield Canal A-1 quadrangles, Alaska: U.S. Geological Survey Bulletin 1425, 49 p., 1 plate.
Reporters	H. C. Berg (Fullerton, California)
Last report date	5/17/1998