1. Mineral Resources
  2. Online Spatial Data
  3. Alaska Resource Data File (ARDF)

Unnamed (east of Arrowhead Peak)

Occurrence, Probably inactive

Map
KML
XML
GeoJSON

Commodities and mineralogy

Main commodities Cr; Fe
Ore minerals chromite; magnetite
Gangue minerals serpentine

Geographic location

Quadrangle map, 1:250,000-scale SI
Quadrangle map, 1:63,360-scale A-4
Latitude 57.0691
Longitude -135.2069
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is near elevation 2245 at the east end of the east spur of Arrowhead Peak. The occurrence is in the NE1/4SE1/4 sec. 27, T. 55 S., R. 64 E. It location 56 of Cobb (1972, 1978). The location probably is accurate within about 0.2 mile.

Geologic setting

Geologic description

This occurrence is near the contact of two similar units of Jurassic and Triassic age (Loney and others, 1975). The Khaz Formation consists of graywacke, greenschist, metachert, phyllite, and minor limestone. The Kelp Bay Group consists of quartzite, greenschist, greenstone, graywacke and semischist, all of which are subject to intense cataclasis.
The occurrence consists of magnetite and chromite in serpentine, which probably are small fault blocks or slivers (Loney and others, 1963). The serpentinite body is too small to be shown on the geologic map of Loney and other (1975). There is no indication that the occurrence is any more than accessory minerals in a small serpentinite body. Samples of diabase or greenstone collected by Loney and others (1963) show small amounts of chromium, nickel, copper, cobalt, and zinc that are little if any above normal background in these types of rocks.
Geologic map unit (-135.208661412608, 57.0687389138763)
Mineral deposit model Accessory magnetite and chromite in serpentine.
Age of mineralization Triassic or younger based on the age of the rocks in the area.

Production and reserves

Workings or exploration Only surface sampling.
Indication of production None

References

MRDS Number A013303

References

Cobb, E.H., 1972, Metallic mineral resources map of the Sitka quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-467, scale 1:250,000.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Sitka quadrangle: U.S. Geological Survey Open-File Report 78-450, 124 p.
Loney, R.A., Berg, H.C., Pomeroy, J.S., and Brew, D.A., 1963, Reconnaissance geologic map of Chichagof Island and northwestern Baranof Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-388, 1 sheet, scale 1:250,000.
Reporters Donald Grybeck (U.S. Geological Survey)
Last report date 5/5/2005