Baraga Group; Copps Formation

Fine- to medium-grained graywacke and less abundant gray to black slate. Thin basal conglomerate west of Lake Gogebic contains clasts of underlying Archean rocks in a quartzitic and argillaceous matrix.
State Michigan
Name Baraga Group; Copps Formation
Geologic age Early Proterozoic
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone > Graywacke (Bed)
Minor
Metamorphic > Metasedimentary > Metaclastic > Slate
Sedimentary > Clastic > Conglomerate (Bed)
Comments Continental margin assemblage (north of Niagara Fault)
References
NGMDB product
Counties Gogebic