Anorthosite.

Metamorphosed anorthosite at Boehls Butte northeast of Elk River (~1787 Ma). Unit is in structural contact with overlying rocks of the Prichard Formation. (Mesoproterozoic to Archean Basement Rocks).
State Idaho
Name Anorthosite.
Geologic age Paleoproterozoic
Lithologic constituents
Major
Metamorphic > Metaigneous > Metaintrusive > Metaanorthosite
References

Lewis, Reed S., Link, Paul K., Stanford, Loudon R., and Long, Sean P., Geologic Map of Idaho, 2012, Idaho Geological Survey, Geologic Map 9 (M-9); Scale 1:500,000.

NGMDB product
Counties Clearwater - Shoshone