Occurrence, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals chalcopyrite; cubanite; pyrite; pyrrhotite; sphalerite
Gangue minerals calcite; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale A-3
Latitude 60.0066
Longitude -147.9343
Nearby scientific data Find additional scientific data near this location
Location and accuracy The occurrence is located 1 mile east of Horseshoe Bay on Latouche Island, at an elevation of about 500 feet. It is in the NE1/4 section 17, T. 2 S., R. 9 E., of the Seward Meridian. This is location 260 of Tysdal (1978 [MF-880-A]) and location S-2 of Jansons and others (1984). This location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

Bedrock in the area consists of northeast-striking, west-dipping interbedded shale and graywacke of the Orca Group of early Tertiary age (Kurtak and Jeske, 1986). The occurrence is along the northwest limb of a shallowly northeast-plunging antiform (Stejer, 1956). The sulfide occurrences in the vicinity of Horseshoe Bay consist of tabular lenses of massive and disseminated sulfides that conform to the stratification of the enclosing bedrock (Stejer, 1956). The ore mineralogy is fairly simple, consisting of pyrite, chalcopyrite, cubanite, sphalerite, and pyrrhotite; gangue minerals consist of quartz, calcite, and epidote (Stejer, 1956). Assay results indicate that small amounts of gold and silver are also present (Stejer, 1956).
Geologic map unit (-147.936315556382, 60.0059447201576)
Mineral deposit model Besshi massive sulfide (Cox and Singer, 1986; model 24b)
Mineral deposit model number 24b
Age of mineralization Tertiary or younger; the mineralization is in rocks of the Orca Group of Tertiary age.
Alteration of deposit There is strong asymmetric sericite-chlorite alteration associated with the massive sulfide mineralization (Rogers and Hoyt, 1999).

Production and reserves

Workings or exploration Grant and Higgins (1909) showed the occurrence as a map location, but no description was given. There are no reported assays or workings.
Indication of production None

Additional comments

There are two prospects owned by Chugach Alaska Corporation with the same name as this occurrence; one is located near Landlocked Bay in the Valdez quadrangle, and the other is located near Humpy Cove in the Blying Sound quadrangle.