Geologic description
The country rocks in the area of the Ibex Saddle prospect are pelitic metasedimentary and subordinate andesitic volcanic 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, 1997; Koch, 1996).
Maas and others (1995, p. 235, 245) describe the deposit as sulfide-bearing silicified (?) andesite. The sulfides are pyrite, galena, and sphalerite. Samples of the deposit collected by the U.S. Bureau of Mines in 1992 or 1993 contain up to 656 ppb Au, 40.7 ppm Ag, 2705 ppm Cu, 2.6 percent Pb, and 7.5 percent Zn. Lead-isotope studies of galena from the Ibex Saddle prospect (Maas and others, 1995, p. 235) indicate that the deposit is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993). |
Age of mineralization |
Lead-isotope studies of galena from the Ibex Saddle prospect (Maas and others, 1995, p. 235) indicate that the deposit is Jurassic in age, contemporaneous, at least in part, with island-arc volcanism in Hazelton time (Alldrick, 1993). |