Diorite and tonalite

Includes Dracut Diorite, tonalite near the Ayer Granite, and equivalents of the Exeter Diorite of New Hampshire; intrudes Sb.
State Massachusetts
Name Diorite and tonalite
Geologic age Devonian and Silurian
Lithologic constituents
Major
Igneous > Plutonic > Dioritic > DioriteDracut Diorite and equivalents of the Exeter Diorite of New Hampshire
Igneous > Plutonic > Granitic > Tonalitetonalite near the Ayer Granite
Comments Part of Merrimack Belt (Silurian, Devonian and Pennsylvanian Rocks)
References
NGMDB product
Counties Essex - Middlesex