Baraga Group; Michigamme Formation, undivided

Thick and stratigraphically varied formation of sedimentary and less abundant volcanic rocks. Metamorphosed graywacke is predominant rock of Michigamme Formation. Calcareous concretions common. Metamorphosed from cholorite to sillimanite grade (Cannon, 1986). Mapped undivided in poorly exposed areas
State Michigan
Name Baraga Group; Michigamme Formation, undivided
Geologic age Early Proterozoic
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Metasandstone > Metagraywacke
Sedimentary > Clastic > Mixed-clastic (Bed)Thick and stratigraphically varied formation of sedimentary and less abundant volcanic rocks.
Minor
Igneous > VolcanicThick and stratigraphically varied formation of sedimentary and less abundant volcanic rocks.
Comments Continental margin assemblage (north of Niagara Fault). This unit description is a combination of descriptions for unit "Xm" [Michigamme Formation, undivided] and unit "Xmgs" [Michigamme Formation, metamorphosed graywacke] as originally published on the Sims (1992) map. Polygons identified on that paper map as "Xm" and "Xmgs" are combined under the single unit symbol "Xm" in this digital product. Reference: Cannon, W.C., 1986, Bedrock geologic map of the Iron River 1o x 2o quadrangle, Michigan and Wisconsin: U.S. Geological Survey Miscellaneous Investigations Series Map I-1360-B, scale= 1:250,000.
References
NGMDB product
Counties Baraga - Dickinson - Gogebic - Houghton - Iron - Marquette - Menominee - Ontonagon