Eastern Alaska Range

Region Alaska, Alaska
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Two clusters of ARDF occurrences connected by remote drainage basins containing metavolcanic rocks indicative of seafloor magmatism that exhibit moderate and high prospectivity.
Identified resources Identified resources of copper, gold, lead, silver, and zinc.
Production None recorded.
Status Current exploration.
Estimated resources Bonnifield area: 8 occurrences have small Inferred resources estimated based on minimal exploration; Healy region: no known resources; Red Mountain: 10 M short tons @ 0.1% Cu, 2.6% Pb, 5.8% Zn, 0.027 oz/t Au, 4.59 oz/t Ag.
Geologic maps Statewide geologic map database; Wilson, Hults and others (2015), scale 1:1,584,000; sparse additional modern mapping at 1:63:360 or better.
Geophysical data Mostly (>90%) inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures In the Healy region: Devonian-Mississippian metavolcanic rocks mixed with minor phyllite, chert and other argillites. Triassic mafic volcanic and volcaniclastic sequences. In Bonnifield region occurrences are predominantly hosted in Devonian-Mississippian schist, argillite and less commonly in carbonate units locally intruded by felsic volcanic units.
Deposits None.
Evidence from mineral occurrences Numerous small ARDF occurrences in both regions.
Geochemical evidence Sediment and soil anomalies in pathfinder elements including Cu, Ag, Pb, Zn, Cd, or Co. Additional geochemical evidence comes from pan concentrates containing anglesite, cerussite, chalcopyrite, copper sulfide/oxide, galena, or sphalerite. Heavy Mineral concentrates containing Cu, Pb, Zn or Ag.
Geophysical evidence No data.
Evidence from other sources Moderate to high potential defined by prospectivity analysis; Karl and others (2016).
Comments Significant areas of high prospectivity potential are determined in drainages with no known volcanogenic seafloor mineralized systems in this region. Two main clusters of occurrences are present on the east and west ends of the belt and are connected by a series of high prospectivity drainages with favorable geologic units.
Cover thickness and description Unknown.
Authors Douglas C. Kreiner, James V. Jones, III.
New data needs New geologic mapping, and well-constrained geochemical sampling.
Geologic mapping and modeling needs Mapping at 1:100,000 scale or better.
Geophysical survey and modeling needs Ensuring entirety of belt is covered by FY19-FY20 aeromagnetic surveys and infill any remaining portions.
Digital elevation data needs IfSAR coverage is complete over entire focus area.