Diorite

Medium-grained hornblende diorite metamorphosed in part to amphibolite and hornblende gneiss.
State Massachusetts
Name Diorite
Geologic age Proterozoic Z
Lithologic constituents
Major
Igneous > Plutonic > Dioritic > DioriteMedium-grained hornblende diorite.
Minor
Metamorphic > Gneiss > Hornblende-gneissmetamorphosed in part to amphibolite and hornblende gneiss
Metamorphic > Amphibolitemetamorphosed in part to amphibolite and hornblende gneiss
Comments Part of Milford-Dedham Zone (Tertiary and Older Rocks)
References
NGMDB product
Counties Bristol - Middlesex - Norfolk - Plymouth