Preston Gabbro

Dark, medium- to coarse-grained, mainly massive gabbro, composed of labradorite, augite, and opaques, generally with hornblende, locally hypersthene, or olivine or both.
State Connecticut
Name Preston Gabbro
Geologic age Middle Ordovician or older
Lithologic constituents
Major
Igneous > Plutonic > Gabbroic > GabbroDark, medium- to coarse-grained, mainly massive gabbro, composed of labradorite, augite, and opaques, generally with hornblende, locally hypersthene, or olivine or both.
Comments Part of Eastern Uplands; Iapetus (Oceanic) Terrane - Merrimack Synclinorium
References

Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 1:125,000.

NGMDB product
Counties New London - Windham