Metapyroxenite and metagabbro (undifferentiated)

Geologic Time Period
Cambrian to Ordovician

Piedmont Unit

The following description is published in GM10 Bedrock Geologic Map of The Piedmont of Delaware and the Adjacent Pennsylvania, Schenck, W.S., Plank, M.O., and Srogi, L., 2000.

Light-colored coarse-grained rocks composed of interlocking grains of light colored, fibrous amphiboles, most likely magnesium-rich cummingtonite and/or anthophyllite with possible clinochlor. These rocks become finer grained and darker as hornblende replaces some of the Mg-rich amphiboles. Associated with the metapyroxenites are coarse-grained metamorphosed gabbros composed of hornblende and plagioclase. The metapyroxenites and metagabbros are probably cumulates.