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

Geologic units in Wadena county, Minnesota

Syntectonic to pretectonic granitoid rocks (Late Archean) at surface, covers 42 % of this area

Syntectonic to pretectonic granitoid rocks - Granite and granodiorite of the Vermilion Granitic Complex, the Giants Range and Bemidji batholiths, as well as smaller intrusions of tonalite and monzonite of the Algoman orogen in northern Minnesota. Also includes the Odessa, Sacred Heart, and Fort Ridgely Granites exposed along the Minnesota River Valley in southwestern Minnesota.

Lithology: granite; granodiorite; tonalite; monzonite

Felsic to intermediate volcanic and volcaniclastic rocks, mica schist, phyllite, and granitoid rocks (Late Archean) at surface, covers 8 % of this area

Felsic to intermediate volcanic and volcaniclastic rocks, mica schist, phyllite, and granitoid rocks - Variably and cataclastically deformed. Unit forms aeromagnetic "quiet zone" and probably contains some rocks of Paleoproterozoic age.

Lithology: felsic volcanic rock; intermediate volcanic rock; schist; phyllite; granitoid

Animikie Group; Shale, siltstone, feldspathic graywacke, and associated volcaniclastic rocks (Early Proterozoic) at surface, covers 46 % of this area

Animikie Group; Shale, siltstone, feldspathic graywacke, and associated volcaniclastic rocks - Includes the Rove Formation in Cook County, the Virginia Formation in St. Louis, Itasca, and Lake Counties, and the Thomson Formation in Carlton County

Lithology: shale; siltstone; graywacke; mixed clastic/volcanic

Mafic metavolcanic rocks (Late Archean) at surface, covers 3 % of this area

Mafic metavolcanic rocks - Dominantly basalt that contains thin sedimentary units, including iron-formation. Includes parts of the Ely Greenstone and the Newton Lake Formation in northeastern Minnesota. Also includes metabasalt exposed in the Minnesota River Valley.

Lithology: basalt; sedimentary rock; iron formation; meta-basalt

Multiphase intrusions of hornblende-pyroxene-bearing and biotite-bearing monzonite, monzodiorite, diorite, syenite, and granodiorite (Late Archean) at surface, covers 0.9 % of this area

Multiphase intrusions of hornblende-pyroxene-bearing and biotite-bearing monzonite, monzodiorite, diorite, syenite, and granodiorite - Typically postdates regional metamorphism and deformation associated with the Algoman orogen.

Lithology: monzonite; monzodiorite; diorite; syenite; granodiorite