Wakefield (Moira Copper prospect), Lake Luelia, Prince of Wales Island, Ketchikan Mining District, Prince of Wales-Hyder Census Area, Alaska, USAi

Regional Level Types
Wakefield (Moira Copper prospect)	- not defined -
Lake Luelia	Lake
Prince of Wales Island	Island
Ketchikan Mining District	Mining District
Prince of Wales-Hyder Census Area	Census Area
Alaska	State
USA	Country

Location: The Wakefield prospect is at an elevation of about 1,300 feet, 1.0 km (3,200 feet) ENE of upper Lake Luelia. It is on the nose of the ridge that extends NNW from elevation 2577, and about 0.4 mile SE of the center of section 29, T78S, R88E.

Geology: 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.

Workings: Explored prior to WW I by a 50-foot shaft, a short adit, and several trenches.

Age: Probably contemporaneous with the deposition of the Silurian or Ordovician host rocks.

Alteration: Greenschist is iron stained and silicified.

Commodities (Major) - Au, Cu; (Minor) - Ag

Development Status: None

Deposit Model: Probably a Bessi-type, volcanogenic massive-sulfide copper deposit (Cox and Sin)

Other Databases

Link to USGS - Alaska:	CR215

Other Regions, Features and Areas containing this locality

References