Iron Bridge

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu
Ore minerals malachite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale SK
Quadrangle map, 1:63,360-scale C-3
Latitude 59.55
Longitude -136.11
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is approximately 3/4 mile north-northwest of the junction of Nataga Creek and the Kelsall River. It is in the NW1/4, section 8, T. 27 S., R. 55 E. of the Copper River Meridian. It is shown as location 3 by Still and others (1991) and as location 28 by Gilbert and others (1991).

Geologic setting

Geologic description

This prospect consists of malachite-stained silicified rocks that occur in metamorphosed volcanic and sedimentary rocks (Still and others, 1991). Gilbert and others (1991) reported samples that contained up to 0.041 ppm gold, 5.6 ppm silver, and 2,960 ppm copper. There is very little information about this prospect. Mapping to the east by Gilbert and others (1990) suggests that the metamorphosed volcanic and sedimentary rocks described by Still and others (1991) are a roof pendant within Cretaceous to Tertiary intrusive rocks that are part of the Coast Range batholith.
Geologic map unit (-136.111846603964, 59.5496839199953)
Mineral deposit model Too little information to assign a model type.
Age of mineralization Unknown. The mineralization may be related to Cretaceous to Tertiary plutonic bodies mapped to the east by Gilbert and others (1990).

Production and reserves

Workings or exploration In the 1970s, Mr. Jones, a local prospector, prospected cuts in a newly built logging road. Shallow trenches and stockpiles of malachite-stained silicified rocks were discovered in this thickly overgrown area in 1988 (Still and others, 1991).
Indication of production None

Additional comments

This prospect is immediately west of the Alaska, Chilkat Bald Eagle Preserve.