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Jumbo (near Texas Creek)

Occurrence, Inactive

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Commodities and mineralogy

Main commodities 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 A-1
Latitude 56.053
Longitude -130.207
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Jumbo occurrence near Texas Creek is on or near the boundary of Sections 14 and 23 at an elevation of about 3750 feet on a north-facing mountainside overlooking the West Fork of Texas Creek and about 1.8 mile due east of Texas Lake (Elliott and Koch, 1981, p. 13, loc. 44). The location is probably 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 (Smith, 1977; Koch, 1996).
The deposit (Buddington, 1929, p. 111) is in a graywacke roof pendant in granodiorite and consists of quartz-cemented graywacke breccia in a shear zone 1-3.5 feet wide. The quartz ranges from one-inch stringers to two-foot veins and carries local shoots of galena, pyrite, and chalcopyrite. Some of the graywacke country rock is impregnated with pyrite and a little chalcopyrite. A 10-inch wide intersecting fissure zone contains 6 inches of quartz carrying galena, pyrite, and a little chalcopyrite and sphalerite.
Geologic map unit (-130.208705205897, 56.0526932856168)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Alteration of deposit Graywacke wallrock adjacent to quartz veins is impregnated with sulfide minerals.

Production and reserves

Indication of production None

Additional comments

Prospect originally staked in 1925.

References

MRDS Number A010242

References

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