Casey Glacier Sphalerite Occurrence, Hyder District, Prince of Wales-Outer Ketchikan Borough, Alaska, USA
This page is currently not sponsored. Click here to sponsor this page.
Location: 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.
Geology: 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).
Age: 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: Intense silica and carbonate alteration of brecciated andesite hostrock.
Commodities (Major) - Pb, Zn; (Minor) - Ag, Au, Cu
Development Status: None
Deposit Model: Polymetallic veins
6 entries listed. 6 valid minerals.
The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
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. Koch, R.D., 1996 [In press), Reconnaissance geologic map of the Bradfield Canal quadrangle, southeastern Alaska: U.S. Geological Survey Open-File Report, 1 sheet, scale 1:250,000. Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p. 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.