Geologic description
When first described by Brooks (1902) and Wright and Wright (1908), the property consisted of three claims: the Little Annie, Homestake, and Bluebird. At the Little Annie prospect, at an elevation of about 1,200 feet, quartz stringers oriented N30E, 70 SE in granite contain sparse pyrite and low gold values. The Little Annie may be the 'Bluebird East' prospect of Maas and others (1995), where samples contained negligible gold values. The Bluebird claim, at an elevation of about 1,500 feet, was explored in the early 1900s by a 40-foot shaft and several pits. A 3- to 6-foot-thick quartz vein that contains sparse galena, sphalerite, pyrite, and free gold cuts phyllite and greenschist near a granitic intrusion. Samples reportedly contained up to $40 to $60 a ton in gold (at $20.67 per ounce). Maas and others (1992) describe a vein up to 3 feet thick on the Bluebird claim. The vein strikes about N60W and dips 45 SW; it can be traced for about 90 feet. It consists mostly of smoky quartz with sparse pyrite, hematite, and sulfides. Samples across 0.8 to 2.7 feet of the vein contained 6 to 228 parts per million (ppm) gold, up to 198 ppm lead, and 301 ppm zinc. The wallrock of the vein is silicified. Selected samples from dumps contained up to 1.901 ounces of gold per ton. The age of the rocks in the area has been variously interpreted. Eberlein and others (1983) mapped the strata as locally metamorphosed graywacke of Silurian or Ordovician age, near a large Paleozoic or Mesozoic granitic intrusion. Gehrels (1992) and Maas and others (1995) mapped them as pre-Ordovician metamorphosed volcanic and sedimentary rocks near a Silurian or Ordovician granitic intrusion. Brew (1996) called them Late Proterozoic and Cambrian Wales Group schist, phyllite, and marble, near a Tertiary granitic intrusion of intermediate composition. Most recently, Slack and others (2002) and S.M. Karl (oral communication, 2003) mapped the strata as Silurian and Ordovician, low-grade, regionally metamorphosed sedimentary and volcanic rocks. |