Ultramafic Rocks

Chiefly serpentinite with partly to completely altered dunite, peridotite, pyroxenite, and massive to schistose soapstone; talc-carbonate rock and altered gabbro are common in some bodies.
State Maryland
Name Ultramafic Rocks
Geologic age Early Paleozoic - Late Precambrian (?)
Lithologic constituents
Major
Metamorphic > Metaigneous > Serpentinite
Incidental
Igneous > Plutonic > Ultramafic > Peridotite
Igneous > Plutonic > Ultramafic > Pyroxenite
Igneous > Plutonic > Ultramafic > Peridotite > Dunite
Igneous > Plutonic > Gabbroic > Gabbro
References

Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.

In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at http://www.mgs.md.gov/.

NGMDB product
Counties Baltimore - Carroll - Cecil - Harford - Howard - Montgomery - Baltimore