Geologic description
The country rocks in the area of the Iron Cap prospect are pelitic metasedimentary and subordinate andesitic volcanic strata of the Jurassic or older Mesozoic Hazelton Group; the Triassic Texas Creek Granodiorite, which underlies and locally intrudes the Texas Creek; and the Eocene Hyder Quartz Monzonite, which intrudes the Hazelton and Texas Creek rocks (Smith, 1977; Koch, 1996).
Maas and others (1995, p. 235,245) describe the deposit as lenses and disseminations of pyrite, galena, and sphalerite in quartz-carbonate lenses in Hazelton argillite. Lead-isotope studies of galena from the prospect (Maas and others, p. 235) 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. 245) contain up to 42.9 ppm Ag, 7270 ppm Pb, and 4.76 percent Zn. |
Age of mineralization |
Maas and others (1995, p. 235,245) describe the deposit as lenses and disseminations of pyrite, galena, and sphalerite in quartz-carbonate lenses in Hazelton argillite. Lead-isotope studies of galena from the prospect (Maas and others, p. 235) indicate that the deposit is Jurassic in age, contemporaneous at least in part with island-arc volcanism in Hazelton time (Alldrick, 1993). |