Esmond Granite

Light-gray to pink biotite granite, generally slightly altered, locally foliated. Gradational with Zgmgd. Intrudes Zsg. Esmond Granite occupies nearly 100 sq km in RI and forms an elongate pluton southeast of Woonsocket, RI, of which only the northern part is in MA. Occurs in Dedham batholith. Consists of mottled red and green, mainly massive granite. Coarse-grained facies intrudes Blackstone Group rocks and a related tonalite; fine-grained facies intrudes the tonalite and coarse-grained facies (Hermes and Zartman, 1985). Contact relations with Milford Granite not known, although phases of Milford resemble Esmond. Age of 621 +/-8 Ma (U/Pb methods on zircon by Hermes and Zartman, 1985) is close to age of Milford (Wones and Goldsmith, 1991).
State Massachusetts
Name Esmond Granite
Geologic age Proterozoic Z
Lithologic constituents
Major
Igneous > Plutonic > Granitic > GraniteLight-gray to pink biotite granite, generally slightly altered, locally foliated.
Comments Part of Milford-Dedham Zone (Tertiary and Older Rocks). Secondary unit description per MA007.
References
NGMDB product
Counties Worcester