Unnamed (near the south end of Kataguni Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu; Zn
Ore minerals bornite; chalcopyrite; malachite; pyrite; sphalerite
Gangue minerals calcite; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale SK
Quadrangle map, 1:63,360-scale A-1
Latitude 59.01
Longitude -135.25
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is in beach cliffs on the western coast of Kataguni Island about 0.2 miles from the southern tip of the island. It is shown as localities 48 to 52 in Still (1988).

Geologic setting

Geologic description

Still (1988) indicates that, 'Mineralization is located in metabasalt sea cliffs up to 50 feet high that contain numerous narrow shear zones at various orientations. Some of the shears are silicified and contain copper or copper-zinc mineralization. Samples collected from these 0.2- to 1.4-foot-thick shear-controlled veins contain up to 2.54 ppm gold, 22.5 ppm silver, 6.9% copper, and 2.14% zinc.'
Plafker, Hudson, and Silberling (1979) and Plafker and Hudson (1980) note that on the Chilkat Peninsula the same metabasalts are vesicular and/or amygdaloidal and that well-developed pillow textures are locally present. Based in part on fossil evidence that supports a Late Triassic (Karnian) age, they suggest that the metavolcanics and carbonates may correlate with similar rocks of the Wrangellia terrane. The age of the mineralization is not well established, but can be no older than the Late Triassic age of the host rocks. If the shearing and mineralization are both related to the nearby Chilkat Fault, then the age of the mineralization is probably Tertiary or younger as most movement on the Chilkat Fault has been post-Mesozoic (Lanphere, 1978).
Geologic map unit (-135.251823390086, 59.0096710969596)
Mineral deposit model Au-Ag-Cu-Zn in shear zones in metabasalt.
Age of mineralization The age of the mineralization is not well established, but must be no older than the Late Triassic (Karnian) age of the metabasalts that host the deposit (Plafker, Hudson and Silberling, 1979; Plafker and Hudson, 1980). If the shearing and mineralization are both related to the nearby Chatham Strait Fault, then the age of the mineralization is probably Tertiary or younger as most movement on the Chilkat Fault has been post-Mesozoic (Lanphere, 1978).
Alteration of deposit Epidotization, silicification.

Production and reserves

Indication of production None

Additional comments

This occurrence is within the Chilkat Islands, State Marine Park.

References

MRDS Number 10308233

References

Reporters T.C. Crafford (T. Crafford & Associates, Anchorage)
Last report date 2/4/2001