Geologic description
As described by Wright and Wright (1906, 1908), the workings are a 50-foot shaft with mineralization exposed at the 25-foot level, and several open cuts. There was assessment work as late as 1915. The host rock is greenschist, slate and 'grits.' The deposit consists of a lenticular mass of chalcopyrite 10 feet thick in a 60-foot-thick mineralized layer in the schist that contains considerable pyrite, quartz, and epidote. The Wrights considered the deposit to be similar to the mineralization at the Niblack Mine (CR216). The prospect was examined by Maas and others (1992), who found a flooded shaft, a 17-foot adit, and some trenches. The workings expose a zone up to 100 feet wide of iron-stained, epidote-bearing, silicified greenschist that contains disseminations and layers of pyrite and chalcopyrite. Chip samples 1.3 to 4 feet long contained 221 to 656 parts per billion gold (ppb) and 851 to 7,566 parts per million (ppm) copper. A select sample contained 1,732 ppb gold, 47.2 ppm silver, and 6.57 percent copper. 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. |
