Monk's Hood

Mine, Undetermined

Commodities and mineralogy

Main commodities Hg
Ore minerals cinnabar
Gangue minerals calcite; dolomite

Geographic location

Quadrangle map, 1:250,000-scale DI
Quadrangle map, 1:63,360-scale B-7
Latitude 59.2814
Longitude -158.5427
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Monk's Hood Mine is about in the middle of the Marsh Mountain area, about 0.3 mile east of the center of section 28, T. 10 S., R. 55 W., of the Seward Meridian and about 0.6 mile northwest of the Red Top Mine (DI002). The location is accurate.

Geologic setting

Geologic description

In 1969, William Carlson and Edward Gentzwill as the Arcana Creek Mining Company, began prospecting in the headwaters of Arcana Creek, northwest of the Red Top Mine (DI002). They employed the classical methods of digging pits to bedrock along the creek and panning the samples (D.J. Grybeck, unpublished field notes, 1970, after discussions with Carlson and Gentzwill). They followed encouraging pans that contained cinnabar up the headwater tributary of Arcana Creek which flows eastward in the center of section 28, and then dug pits up to 8 feet deep up the hillside to the south, about 0.3 mile east of the center of the section. (They also prospected up the tributary that extends northwest in the NE 1/4 of section 28; there was little cinnabar in the pans for a short distance and then none at all.)
The rocks in the area are interbedded, very fine- to very coarse-grained graywacke, calcareous graywacke, and siltstone. Wilson and others (2006) include them in their 'Graywacke of Kululak Bay' unit of Middle and Upper Jurassic age.
The pits and hand trenching on the hillside uncovered two good shows of mineralization. The best is a 1/2- to 3-inch vein of carbonates with disseminated and massive cinnabar that extends for at least 100 feet; it strikes N 80 E and dips 70S. The other is along a gouge zone several inches thick that strikes N 70 E and dips 18S; at one place along it there was a disseminated-cinnabar-bearing carbonate lens about 8 feet long, 4 feet deep, and about 18 inches thick. In 1969, about 700 pounds of ore was hand mined from these showings and a flask of mercury was retorted from it. Some trenching with a tractor was attempted in 1969 but the hillside has discontinuous permafrost and the trenching generally did not reach bedrock. It is unclear whether there was work after 1970 but Carlson and Gentzwill found considerable mineralized float above and below the pits that exposed the mineralization. The mineralization is similar to that at the nearby Red Top Mine (DI002).
Geologic map unit (-158.54490009902, 59.2806575372451)
Mineral deposit model Cinnabar veins (Cox and Singer, 1986; model 27b).
Mineral deposit model number 27b
Age of mineralization Jurassic or younger based on the age of the host rocks; probably Cretaceous or Tertiary by analogy with other mercury deposits in southwestern Alaska.
Alteration of deposit Not specifically noted but probably similar to that at the better-known, nearby Red Top Mine (DI002).

Production and reserves

Workings or exploration In 1969, William Carlson and Edward Gentzwill as the Arcana Creek Mining Company, began prospecting in the headwaters of Arcana Creek, northwest of the Red Top Mine (DI002). They employed the classical methods of digging pits to bedrock along the creek and panning the samples (D.J. Grybeck, unpublished field notes, 1970, after discussions with Carlson and Gentzwill). They followed encouraging pans that contained cinnabar up the headwater tributary of Arcana Creek which flows eastward in the center of section 28, and then dug pits up to 8 feet deep up the hillside to the south, about 0.3 mile east of the center of the section. (They also prospected up the tributary that extends northwest in the NE 1/4 of section 28; there was little cinnabar in the pans for a short distance and then none at all.) Some trenching with a tractor was attempted in 1969 but the hillside has discontinuous permafrost and the trenching generally did not reach bedrock. It is unclear whether there was work after 1970.
Indication of production Yes; small
Reserve estimates Probably none.
Production notes One flask of mercury was retorted from 700 pounds of ore mined by hand from surface pits.

References

Reporters D.J. Grybeck (Contractor, U.S. Geological Survey)
Last report date 4/2/2010