Gneiss and amphibolite (Late Archean, 2.640-2.750 Ma) (MIWga;0)

Gneiss and amphibolite (Late Archean, 2.640-2.750 Ma) - Interlayered quartzofeldspathic gneiss and amphibolite in Marenisco, Mich., area and northwestern Wisconsin. Protoliths are bimodal intermediate and mafic volcanic rocks (Sims and others, 1984).

State	Michigan
Name	Gneiss and amphibolite (Late Archean, 2.640-2.750 Ma)
Geologic age	Late Archean
Original map label	Wga
Comments	continental margin assemblage (north of Niagara Fault). Sims and others, 1984, Geology, geochemistry, and age of Archean and Early Proterozoic rocks in the Marenisco-Watersmeet area, northern Michigan: U.S. Geological Survey Professional Paper 1292-A,. p. A1-A41.
Primary rock type	gneiss
Secondary rock type	amphibolite
Other rock types
Lithologic constituents	Major Metamorphic > Amphibolite Metamorphic > Gneiss
Map 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]
Unit references	Sims and others, 1984, Geology, geochemistry, and age of Archean and Early Proterozoic rocks in the Marenisco-Watersmeet area, northern Michigan: U.S. Geological Survey Professional Paper 1292-A,. p. A1-A41. [http://pubs.er.usgs.gov/publication/pp1292AB]
Geographic coverage	Baraga - Gogebic - Marquette