Last Shot

Prospect, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Other commodities W
Ore minerals chalcopyrite; freibergite; galena; pyrite; pyrrhotite; scheelite; sphalerite; tetrahedrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale D-1
Latitude 55.995
Longitude -130.057
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at about 1400 feet elevation, about 0.2 mile west of Skookum Creek, and about 5.5 miles north-northwest of Hyder. It is in the north-central part of section 11, T. 68 S., R. 99 E., of the Copper River Meridian. The site corresponds to loc. 10 on plate 2 in Buddington (1929 [B 807]), and to loc. 2 in Elliott and others (1978). The location is accurate within about 0.1 mile.

Geologic setting

Geologic description

The country rocks in the area of this site include: pelitic metasedimentary and subordinate andesitic metavolcanic strata of the Jurassic or Triassic Hazelton Group; recrystallized granodiorite of the Triassic Texas Creek Granodiorite, which intrudes the Hazelton rocks; quartz monzonite and granodiorite of the Hyder Quartz Monzonite batholith, which intrudes the Hazelton and Texas Creek rocks; and Tertiary lamprophyre dikes, which intrude all of the foregoing rock units (Smith, 1973, l977; Berg and others, 1988).
The deposit is in (Texas Creek) granodiorite and consists of sulfide-bearing quartz veins and stringer lodes, and of pyritized country rock adjacent to the veins (Buddington, 1929, p. 75-76; Elliott and others, 1978, loc. 2; Cobb and Elliott, 1980, p. 65). The principal vein is as much as 12 feet thick and contains an ore shoot of almost solid sulfides 8 to 18 inches thick, exposed for a length of at least 30 feet. The sulfide minerals are galena, pyrite, sphalerite, pyrrhotite, chalcopyrite, tetrahedrite, and freibergite.
The principal vein was explored in the early 1900s by surface pits and opencuts, and by a 25-foot adit. A 26-inch-long channel sample of the vein taken in 1951 contained 0.08 oz. Au/ton, 6.2% Pb, and 4.85% Cu (Byers and Sainsbury, 1956, p. 56). Altered (talcose) country rock adjacent to the vein contains sparsely disseminated grains of scheelite.
Maas and others (1995, p. 254) suggest that the age of the sulfide-bearing quartz fissure vein at the Last Shot prospect (p. 261 and fig. 66) is Eocene, based on similarities in mineralogy, structural setting, and hostrock, to lead-isotope-dated Eocene deposits nearby in the Hyder district. If so, the age of the deposit is roughly contemporaneous with emplacement of the Hyder Quartz Monzonite batholith.
Geologic map unit (-130.058704209516, 55.9947044713728)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization Maas and others (1995, p. 254) suggest that the age of the sulfide-bearing quartz fissure vein at the Last Shot prospect (p. 261 and fig. 66) is Eocene, based on similarities in mineralogy, structural setting, and hostrock, to lead-isotope-dated Eocene deposits nearby in the Hyder district. If so, the age of the deposit is contemporaneous with emplacement of the Hyder Quartz Monzonite batholith.

Production and reserves

Workings or exploration The principal vein was explored in the early 1900s by surface pits and opencuts, and by a 25-foot adit. A 26-inch-long channel sample of the vein taken in 1951 contained 0.08 oz. Au/ton, 6.2% Pb, and 4.85% Cu (Byers and Sainsbury, 1956, p. 56). Altered (talcose) country rock adjacent to the vein contains sparsely disseminated grains of scheelite.
Indication of production None

References

MRDS Number A012280

References

Smith, J.G., 1973, A Tertiary lamprophyre dike province in southeastern Alaska: Canadian Journal of Earth Sciences, v. 10, p. 408-420.
Reporters H.C. Berg, USGS
Last report date 6/28/1999