Alkalic basalt, greenstone, and actinolite schist. Includes metamorphosed volcanoclastic rocks and iron-rich schist.
State South Dakota
Name Metabasalt
Geologic age Early Proterozoic
Lithologic constituents
Metamorphic > Metaigneous > Metavolcanic > Metabasaltalkalic metabasalt
Metamorphic > Schist > Amphibole-schistactinolite schist, iron-rich schist
Metamorphic > Metaigneous > Greenstone

Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D., 2004, Geologic Map of South Dakota: South Dakota Geological Survey, GM 10, scale 1:500,000.

NGMDB product
Counties Custer - Lawrence - Pennington