Geologic description
The country rocks in the area of the Dog Hole prospect 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, 244) describe the deposit as sulfide-bearing silicified (?) Hazelton volcanic rock and argillite. The sulfides are pyrite, galena, and sphalerite. Lead-isotope studies of galena from the prospect indicate that the deposit is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993). Samples of the deposit collected by the U.S. Bureau of Mines in 1992 or 1993 (Maas and others, 1995, p. 244) contain up to 1.3 ppm Ag, 30.1 ppm Ag, 0.84 percent Pb, and 2.17 percent Zn. |
Age of mineralization |
Maas and others (1995, p. 235, 244) describe the deposit as sulfide-bearing silicified (?) Hazelton volcanic rock and argillite. The sulfides are pyrite, galena, and sphalerite. Lead-isotope studies of galena from the prospect indicate that the deposit is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993). |