Amphibolite

Gray- to grayish-black, medium-grained amphibolite composed of hornblende and andesine. Some phases contain biotite and (or) clinopyroxene. Ubiquitous and associated with almost all other Middle Proterozoic units. Some amphibolite is clearly metavolcanic in origin, some is metasedimentary, and some appears to be metagabbro.
State New Jersey
Name Amphibolite
Geologic age Middle Proterozoic
Lithologic constituents
Major
Metamorphic > AmphiboliteGray- to grayish-black, medium-grained amphibolite composed of hornblende and andesine. Some phases contain biotite and (or) clinopyroxene.
Comments Rocks of Uncertain Origin (Middle Proterozoic)
References

Dalton, R.F., Herman, G.C., Monteverde, D.H., Pristas, R.S., Sugarman, P.J., and Volkert, R.A., 1999, New Jersey Department of Environmental Protection, Bedrock Geology and Topographic Base Maps of New Jersey: New Jersey Geological Survey CD Series CD 00-1; ARC/INFO (v. 7.1), scale 1:100,000.

Drake, Avery A. Jr.,Volkert, Richard, A., Monteverde, Donald H., Herman, Gregory C., Houghton,Hugh F., Parker, Ronald A., and Dalton, Richard F., 1996, Bedrock Geologic Map of Northern New Jersey: U.S. Geological Survey Miscellanenous Investigations Map I-2540-A, 4 cross sections, 2 sheets, size 56x40; 58x41, scale 1:100.000.

https://pubs.er.usgs.gov/publication/i2540A

NGMDB product
Counties Bergen - Hunterdon - Morris - Passaic - Somerset - Sussex - Warren