USGS Home
Contact USGS
Search USGS

Mineral Resources > Online Spatial Data > Geology > by state > Wisconsin Geology

Geologic units in Chippewa county, Wisconsin

Cambrian, undivided (Cambrian) at surface, covers 71 % of this area

Cambrian, undivided - Sandstone with some dolomite and shale, undivided; includes Trempealeau, Tunnel City, and Elk Mound Formations

Lithology: sandstone; dolostone (dolomite); shale

Granitic rocks, undivided (Early Proterozoic) at surface, covers 1 % of this area

Granitic rocks, undivided - Gray, weakly foliated to massive granite in poorly exposed areas.

Lithology: granite

Mafic to felsic metavolcanic rocks (Early Proterozoic) at surface, covers 0.6 % of this area

Mafic to felsic metavolcanic rocks - Volcanic rocks in areas of sparse geologic data and nondefinitive magnetic and gravity data

Lithology: mafic metavolcanic rock; felsic metavolcanic rock

Granite-tonalite (Early Proterozoic) at surface, covers 0.1 % of this area

Granite-tonalite - Gray to pinkish-gray, medium-grained, generally equigranular granite to tonalite and granitoid gneiss; locally includes diorite. Intrudes older metavolcanic rocks. Zircon ages range from 1852 +/- 15 to 1862 +/- 5 Ma

Lithology: granite; tonalite; gneiss

Quartzite (Early Proterozoic) at surface, covers 0.5 % of this area

Quartzite - Maroon but locally white, gray, and red quartzite (quartz arenite) with a basal quartzose conglomerate. At Flambeau Ridge (Chippewa County) consists of conglomerate. Distinguished from other quartzite units in being strongly deformed and metamorphosed. Includes Flambeau, Rib Mountain, McCaslin, and Thunder Mountain Quartzites of local usage

Lithology: quartzite; conglomerate

Felsic volcanic and volcanogenic rocks (Early Proterozoic) at surface, covers 3 % of this area

Felsic volcanic and volcanogenic rocks - Tuff, argillite, graywacke, and minor volcanic rocks of lower greenschist-facies in southern Rusk County. Could be younger in age than adjacent metavolcanic rocks.

Lithology: tuff; argillite; graywacke

Gneiss, migmatite, and amphibolite (about 2800 Ma) (Late Archean) at surface, covers 24 % of this area

Gneiss, migmatite, and amphibolite (about 2800 Ma) - Quartzofeldspathic gneiss and less abundant amphibolite and migmatite. Includes granitoid rocks. Granitic gneiss at Port Edwards, WI on Wisconsin River has a U-Pb zircon age of 2870 +/- 13 Ma, and gneiss at Jim Falls in Chippewa River valley has a U-Pb zircon age of 2522 +/- 22 Ma (Sims and others, 1989)

Lithology: gneiss; amphibolite; migmatite; granitoid