Biotite schist (Lake Archean) (MIWs;0)

State	Michigan
Name	Biotite schist (Lake Archean)
Geologic age	Late Archean
Original map label	Ws
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".
Primary rock type	mica schist
Secondary rock type	gneiss
Other rock types
Lithologic constituents	Major Metamorphic > SchistQuartz-plagioclase-biotite schist Minor Metamorphic > GneissQuartz-plagioclase-biotite schist
Map references	Cannon, W.F., Kress, T.H., Sutphin, D.M., Morey, G.B., Meints, Joyce, and Barber-Delach, Robert, 1997, Digital Geologic Map and mineral deposits of the Lake Superior Region, Minnesota, Wisconsin, Michigan: USGS Open-File Report 97-455 (version 3, Nov. 1999), on-line only
Unit references	Sims, P.K., 1992, Geologic map of Precambrian rocks, southern Lake Superior region, Wisconsin and northern Michigan: U.S. Geological Survey Miscellaneous Investigations Map I-2185, scale= 1:500,000 [http://pubs.er.usgs.gov/publication/i2185] Cannon, W.F., Kress, T.H., Sutphin, D.M., Morey, G.B., Meints, Joyce, and Barber-Delach, Robert, 1997, Digital Geologic Map and mineral deposits of the Lake Superior Region, Minnesota, Wisconsin, Michigan: USGS Open-File Report 97-455 (version 3, Nov. 1999), on-line only
Geographic coverage	Gogebic