Gabbro

Medium- to coarse-crystalline, medium- to dark-gray foliated rock composed principally of plagioclase (An35) and clinopyroxene. Contains minor amounts of garnet, biotite, and sulfide. The rock is more siliceous than typical gabbros.
State New Jersey
Name Gabbro
Geologic age Middle Proterozoic
Lithologic constituents
Major
Igneous > Plutonic > Gabbroic > GabbroMedium- to coarse-crystalline, medium- to dark-gray foliated rock composed principally of plagioclase (An35) and clinopyroxene. Contains minor amounts of garnet, biotite, and sulfide. The rock is more siliceous than typical gabbros.
Comments Rocks of the Trenton prong
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.

Owens, James P., Sugarman, Peter J., Sohl, Norman F., Parker, Ronald A., Houghton, Hugh F., Volkert, Richard A., Drake, Avery A., Jr., and Orndorff, Randall C., 1998, Bedrock Geologic Map of Central and Southern New Jersey: U.S. Geological Survey Miscellaneous Investigations Series Map I-2540-B, 8 cross sections, 4 sheets, each size 58x41, scale 1:100,000.

https://pubs.er.usgs.gov/publication/i2540B

NGMDB product
Counties Mercer