Metagabbro

Dark-green sills of amphibolite, actinolite schist, greenstone, and serpentine. Thickness of sills variable, up to 1,000 ft (305 m).
State South Dakota
Name Metagabbro
Geologic age Early Proterozoic
Lithologic constituents
Major
Metamorphic > Amphibolite
Metamorphic > Schist > Amphibole-schistactinolite schist
Metamorphic > Metaigneous > Greenstone
Minor
Metamorphic > Metaigneous > Serpentinite
References

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