Merrimack Group, Berwick Formation

Purple biotite-quartz-feldspar granofels or schist and interbeds of calc-silicate granofels and minor metapelites. Stratigraphic sequence with respect to Eliot Formation uncertain
State New Hampshire
Name Merrimack Group, Berwick Formation
Geologic age Ordovician? - Silurian?
Lithologic constituents
Major
Metamorphic > Granoblastic > Granofelspurple biotite-quartz-feldspar granofels, interbeds of calc-silicate granofels
Metamorphic > Schist > Mica-schist > Biotite-schistbiotite-quartz-feldspar schist, minor metapelites
Incidental
Metamorphic > Metasedimentary > Calc-silicate-rock
Comments Part of the Nashoba-Casco-Miramichi Terrane (Merrimack Trough). Biotite granite dike (point within formation) = 381+/-2 U/Pb per NH002 (map page 2).
References
NGMDB product
Counties Hillsborough - Merrimack - Rockingham - Strafford