Portage Creek

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale LC
Quadrangle map, 1:63,360-scale B-3
Latitude 60.385
Longitude -154.01
Nearby scientific data Find additional scientific data near this location
Location and accuracy Prospect is located about 3.6 km north of the mouth of Portage Creek. Locality 23 of Nelson and others (1985) and locality 15 of MacKevett and Holloway (1977). Sec. 5, T. 3 N., R. 27 W., of the Seward Meridian. Locality accurate within 800 m.

Geologic setting

Geologic description

Only information is that lode claims (U.S. Bureau of Mines, 1973) are located along part of the Lake Clark fault.
Near the claims, the fault separates metamorphic rocks of Paleozoic to Mesozoic age and Tertiary volcanic rocks. The claims appear to straddle the Lake Clark Fault and span both lithologies. According to Nelson and others (1983, unit MzPzm), metamorphosed mafic volcanic rocks are the most widespread rocks of this unit; they are aphanitic and were probably originally composed of plagioclase and pyroxene, and locally olivine and amphibole. These rocks have been altered, and they now consist mostly of chlorite, epidote, and fibrous amphibole. Other lithologies of this unit include: phyllite, schist, quartzite, marble, calc-silicate rocks, serpentinite, gabbro, and chert. Unit Tv is described by Nelson and others (1983) to include rhyolitic breccia, ash-flow tuff, flows, and intrusive rocks and subordinate mafic to intermediate flows. Potassium-argon ages for unit Tv range from 56.2 to 62.7 m.y. indicating a Tertiary age for these rocks (Eakins and others, 1978).
Geologic map unit (-154.012223968323, 60.3843383711559)
Mineral deposit model Unknown
Age of mineralization Unknown
Alteration of deposit The metamorphic rocks consist mostly of chlorite, epidote, and fibrous amphibole (Nelson and others, 1983).

Production and reserves

Workings or exploration Unknown
Indication of production None
Reserve estimates No reserves
Production notes No production

Additional comments

Site is in Lake Clark National Park and Preserve.