Littlejohn

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au; Hg
Other commodities Ag; As
Ore minerals pyrite
Gangue minerals quartz; clay

Geographic location

Quadrangle map, 1:250,000-scale CB
Quadrangle map, 1:63,360-scale A-3
Latitude 55.034
Longitude -162.865
Nearby scientific data Find additional scientific data near this location
Location and accuracy Two miles east of Littlejohn Lagoon, north side of north fork of creek. Probably anomaly no. 63 of Christie (1974).

Geologic setting

Geologic description

Strongly argillized vesicular andesite containing areas of silicified rock. Initially reported as having rare quartz veins and disseminated Au and Hg (Trujillo and others, 1982), later work (Butherus, 1984) showed Au and Hg to be limited to vertical fault or shear that localizes reticulated quartz veins.
Geologic map unit (-162.867005868747, 55.0331198355773)
Mineral deposit model Epithermal gold vein, hot springs gold-silver, Hot spring disseminated gold (Silberman and Berger, 1985).
Mineral deposit model number 25a, 25d
Age of mineralization Pliocene or younger
Alteration of deposit Propylitic alteration, inferred from presence of chlorite (Christie, 1974).

Production and reserves

Workings or exploration Christie (1974) reported brief reconnaissance geologic mapping and collection of a few silt samples as part of a porphyry copper evaluation. Trujillo and others (1982) and Butherus (1984) collected 269 samples and did geologic mapping, collecting 45 samples in 1982 and 224 in 1984. Their samples showed gold to 5.6 ppm and silver to 33.2 ppm whereas Christie's (1974) were at background levels.
Indication of production None

Additional comments

Good example of how color anomaly evaluation focused on copper porphyry mineralization (Christie, 1974) might miss epithermal gold vein type mineralization.

References

MRDS Number A106060

References

Butherus, D.L., 1984, Exploration and evaluation of northern Akun Island and Walrus Peak-Littlejohn areas, Aleut Native Corporation Lands, 1984: Resource Associates of Alaska, 14 p., 4 appendices (Report held by the Aleut Corporation, Anchorage, Alaska.)
Christie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps. (Report held by the Aleut Corporation, Anchorage, Alaska.)
Trujillo, R.S., Tapper, C.J., Alvarez, T.J., Porterfield, Ben, and Toupe, W.M., 1982, Exploration and evaluation of precious metal potential of portions of Aleut Corporation lands, southwest Alaska 1982: Resource Associates of Alaska unpublished report, 91 p, 33 maps, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)
Reporters Frederic Wilson
Last report date 5/9/1994