|Quadrangle map, 1:250,000-scale||BC|
|Quadrangle map, 1:63,360-scale||A-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||
The Blasher prospect is in Section 16 at an elevation of about 2600 feet approximately 0.3 mile northwest of Texas Lake (Elliott and Koch, 1981, p. 12, loc. 32). The location is accurate to within about a quarter of a mile.Also see Additional Comments field, below.
The country rocks in the area of the Blasher prospect include pelitic metasedimentary and subordinate andesitic metavolcanic strata of the Jurassic or older Mesozoic Hazelton Group; the Triassic Texas Creek Granodiorite, which underlies and locally intrudes the Hazelton; and the Eocene Hyder Quartz Monzonite, which intrudes both the Hazelton and Texas Creek rocks (Smith, 1977; Berg and others, 1977, p. 15-18, 22-23; Koch, 1996).
Buddington (1929, p. 100) describes the deposit as a shattered and fissured zone in quartzite, less than 200 feet above the contact of the Texas Creek Granodiorite. The zone, traced along strike for about 1500 feet, contains a quartz vein about 4 feet thick and many mineralized quartz stringers. The veins carry galena, pyrite, sphalerite, and minor chalcopyrite. A short adit driven in argillite to undercut the lode encountered quartz veinlets containing disseminated molybdenite.
Berg and others (1977, p. 38-39, 72, 85-89) describe the deposit as a quartz vein up to 2 feet thick and exposed along strike for about 140 feet . The hostrocks are Hazelton hornfels and quartz monzonite that is interpreted as a cupola of the Texas Creek Granodiorite. The vein contains erratically distributed chalcopyrite, galena, sphalerite, pyrrhotite, pyrite, and molybdenite. A weighted average of assay data over the exposed length of the vein gives 0.93 percent Cu, 1.15 percent Pb, 1.25 percent Zn, 0.002 percent Mo, and 4.4 oz Ag and 0.016 oz Au per ton. Small amounts of powellite are present locally in the vein, and the quartz monzonite and hornfels country rocks locally contain sparse molybdenite.Lead-isotope studies of galena from the Blasher prospect (Maas and others, 1995, p. 244) indicate that the deposit is Eocene in age, contemporaneous with emplacement of the Hyder Quartz Monzonite.
|Geologic map unit||(-130.266705432284, 56.0556888828041)|
|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 the Blasher prospect (Maas and others, 1995, p. 244) indicate that the deposit is Eocene in age, contemporaneous with emplacement of the Hyder Quartz Monzonite.|
|Alteration of deposit||Hostrock identified as quartzite may have formed by silicification of pelitic country rock.|
|Workings or exploration||
Property has been explored by a short drift, surface opencuts, trenches, and pits, and seven diamond drillholes.A weighted average of assay data over the exposed length of the vein gives 0.93 percent Cu, 1.15 percent Pb, 1.25 percent Zn, 0.002 percent Mo, and 4.4 oz Ag and 0.016 oz Au per ton (Berg and others, 1977).
|Indication of production||None|
Additional commentsThe Blasher prospect was originally staked in 1923, restaked several times, and covered in 1970-71 by the Lone Star group of 32 claims (Berg and others, 1977, p. 85).
Berg, H.C., Elliott, R.L., Smith, J.G., Pittman, T.L., and Kimball, A. L., 1977, Mineral resources of the Granite Fiords Wilderness Study Area, Alaska, with a section on aeromagnetic data by Andrew Griscom: U.S. Geological Survey Bulletin 1403, 151 p.
|Reporters||H. C. Berg (Fullerton, California)|
|Last report date||5/17/1998|