Roxbury Conglomerate

Melaphyre in the Roxbury Conglomerate. Brighton Melaphyre lies within Brookline Member and consists of mafic volcanic rocks (quartz keratophyre, keratophyre, and spilite). Roxbury clearly lies nonconformably on Dedham Granite near Hull, MA; can be traced continuously over Mattapan Volcanic Complex. Age is Proterozoic Z and possibly Early Cambrian (Goldsmith, 1991).
State Massachusetts
Name Roxbury Conglomerate
Geologic age Proterozoic Z to earliest Paleozoic
Lithologic constituents
Igneous > Volcanic > Mafic-volcanicmelaphyre; mafic volcanic rocks (quartz keratophyre, keratophyre, and spilite)
Comments Part of Milford-Dedham Zone (Tertiary and Older Rocks). Secondary unit description per MA023.
NGMDB product
Counties Middlesex - Norfolk - Plymouth - Suffolk