Derby pluton - granodiorite and tonalite

Light-gray, medium- to coarse-grained, massive, epidote-biotite-muscovite porphyritic granodiorite and minor tonalite. Rb/Sr whole-rock isochron age of 370±17 Ma (Ayuso and Arth, 1992). Igneous rocks of the Northeast Kingdom batholith of Ayuso and Arth (1992). Part of the New Hampshire Plutonic Suite.
State Vermont
Name Derby pluton - granodiorite and tonalite
Geologic age Devonian
Lithologic constituents
Major
Igneous > Plutonic > Granitic > GranodioriteLight-gray, medium- to coarse-grained, massive, epidote-biotite-muscovite porphyritic granodiorite.
Minor
Igneous > Plutonic > Granitic > Tonalite
References
NGMDB product
Counties Caledonia - Orleans