Leucogranitic (alaskitic) gneiss

Sodic plagioclase ranges from generally subordinate to locally dominant; locally with biotite, hornblende, pyroxene, garnet, sillimanite, disseminated magnetite; commonly contains metasedimentary layers, amphibolite, migmatite; plagioclase-rich variety is host to magnetite ore bodies in eastern Adirondacks.
State New York
Name Leucogranitic (alaskitic) gneiss
Geologic age Middle Proterozoic
Lithologic constituents
Major
Metamorphic > GneissLeucogranitic (alaskitic) gneiss
Minor
Metamorphic > Amphibolite
Metamorphic > Migmatite
Metamorphic > Metasedimentarycommonly contains metasedimentary layers
References

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic Map of New York State, consisting of 5 sheets: Niagara, Finger Lakes, Hudson-Mohawk, Adirondack, and Lower Hudson, New York State Museum and Science Service, Map and Chart Series No. 15, scale 1:250,000.

NGMDB product
Counties Essex - Franklin - Hamilton - Herkimer - Jefferson - Lewis - Saint Lawrence - Warren - Washington