Biotite schist

Quartz-plagioclase-biotite schist of probably intermediate volcanic protolith in area south of Gogebic Range
State Michigan
Name Biotite schist
Geologic age Late Archean
Lithologic constituents
Major
Metamorphic > Schist > Quartz-feldspar-schistQuartz-plagioclase-biotite schist
Minor
Metamorphic > GneissQuartz-plagioclase-biotite schist
Comments Continental margin assemblage (north of Niagara Fault). Note that on original map (Sims, 1992), this unit's map symbol was "Wbs". This was shortened to "Ws" in digital version (Cannon et al, 1997) and that convention is followed here. Unit description above is from Sims (1992) for the unit labeled "Wbs".
References
NGMDB product
Counties Gogebic