Hoosac Formation

Green to gray-green chlorite-sericite-quartz phyllite; interbeds of chloritoid- or albite-rich schist and minor quartzite, locally rich in garnet and kyanite.
State Massachusetts
Name Hoosac Formation
Geologic age Lower Cambrian and Proterozoic Z
Lithologic constituents
Major
Metamorphic > Schist > Quartz-feldspar-schistinterbeds of chloritoid- or albite-rich schist; locally rich in garnet and kyanite
Metamorphic > Metasedimentary > Metaclastic > Phyllitegreen to gray-green chlorite-sericite-quartz phyllite; locally rich in garnet and kyanite
Minor
Metamorphic > Metasedimentary > Metaclastic > Quartzitelocally rich in garnet and kyanite
Comments Part of Taconic-Berkshire Zone (Ordovician and Older Rocks); east of Berkshire Highlands
References
NGMDB product
Counties Berkshire - Hampshire