Good example of how color anomaly evaluation focused on copper porphyry mineralization (Christie, 1974) might miss epithermal gold vein type mineralization.
Location: Two miles east of Littlejohn Lagoon, north side of north fork of creek. Probably anomaly no. 63 of Christie (1974).
Geology: 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.
Workings: 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.
Age: Pliocene or younger
Alteration: Propylitic alteration, inferred from presence of chlorite (Christie, 1974).
Commodities (Major) - Au, Hg; (Minor) - Ag, As
Development Status: No
Deposit Model: Epithermal gold vein, hot springs gold-silver, Hot spring disseminated gold (Si
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 Christie, J.S., 1974, Aleut-Quintana-Duval 1974 joint venture, final report: Unpublished Quintana Minerals Corporation report, 24 p., 3 appendices, 2 maps.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precious metal potential of portions of Aleut Corporation lands, southwest Alaska 1982: Resource Associates of Alaska unpublished report, 91 p, 33 maps, various scales.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.)
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Map Reference: 55°2'2"N , 162°51'54"W
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Mineral List:3 entries listed. 2 valid minerals.
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