Unnamed

Occurrence, Inactive

Commodities and mineralogy

Geographic location

Quadrangle map, 1:250,000-scale TL
Quadrangle map, 1:63,360-scale C-4
Latitude 62.712
Longitude -151.825
Nearby scientific data Find additional scientific data near this location
Location and accuracy C.C. Hawley and Associates, Inc. (1978, sample site no. 234, Figure 4.0-B) show this occurrence between the Dall and the Yentna Glaciers in the northwest quarter of T. 30 N., R. 14 W., of the Seward Meridian in Denali National Park and Preserve.

Geologic setting

Geologic description

This occurrence is described by C.C. Hawley and Associates, Inc. (1978) as a pod of massive sulfides, mainly pyrrhotite, with exposed dimensions of 4 feet by 20 feet. Assays from the massive sulfides contained as much as 0.14% copper, 0.17% nickel, 0.08% chrome. Soil samples from this part of the ultramafic belt contained values as high as 1500 ppm copper and 6000 ppm nickel.
This is one of several chromite occurrences in a 25-mile long belt of alpine-type ultramafic bodies described by C.C. Hawley and Associates, Inc. (1978, Fig. 4.1-(C)3 and Fig. 4.0-B), as part of the Dall Trend, that are discontinuously exposed from the Dall Glacier northeast to the Lacuna Glacier. These chromite- and magnetite-bearing dunite and peridotite sills are shown by Reed and Nelson (1980) in a narrow belt of middle to upper Paleozoic sedimentary rocks that are exposed between the middle Tertiary (38 m.y.) Foraker pluton and the northwest-trending fault which places the Paleozoic rocks over the Mesozoic marine sedimentary rocks (KJs). Foley and others (1997, p. 431) suggest that these ultramafic bodies may be genetically related to the composite plutons (Tcp) of Reed and Nelson (1980) in the upper Yentna River.
Other chromite occurrences in this trend are described in TL002, TL003, TL008 - 010, TL012, and TL055.
Geologic map unit (-151.827244802549, 62.7114544026052)
Mineral deposit model Podiform chromite (Cox and Singer, 1986; model 8a).
Mineral deposit model number 8a
Age of mineralization Mesozoic and (or) Paleozoic (Reed and Nelson, 1980) or Late Cretaceous/early Tertiary (?) (Foley and others, 1997).

Production and reserves

Workings or exploration Reconnaissance mapping, stream silt and rock sampling are all that have been done here. Assays from the massive sulfides contained as much as 0.14% copper, 0.17% nickel, 0.08% chrome. Soil samples from this part of the ultramafic belt contained values as high as 1500 ppm copper and 6000 ppm nickel.
Indication of production None

Additional comments

Mineral occurrences in the Dall Trend are all within Denali National Park and Preserve.

References