Geologic units in Price county, Wisconsin

Mafic metavolcanic rocks (Early Proterozoic) at surface, covers 34 % of this area

Dominantly tholeiitic basalt and basaltic andesite flows and tuffs; associated with sheet dikes, massive and layered metagabbro, and ultramafic rocks. In northeastern Wisconsin, rocks have been named the Quinnesec Formation.

Mafic to felsic metavolcanic rocks (Early Proterozoic) at surface, covers 22 % of this area

Volcanic rocks in areas of sparse geologic data and nondefinitive magnetic and gravity data

Granite-tonalite (Early Proterozoic) at surface, covers 20 % of this area

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

Biotite schist (Early Proterozoic) at surface, covers 14 % of this area

Metamorphosed graywacke in poorly exposed areas in northwestern Wisconsin. Sample at one locality (near Blockhouse Lake, 10 km northeast of Park Falls, T. 40 N., R. 1 E.) has a U-Pb zircon age of 1852 +/- 6 Ma (Sims and others, 1985b)

Granitic rocks of 1760-Ma age group (Early Proterozoic) at surface, covers 6 % of this area

In northern Wisconsin, granite to granodiorite of varied texture. In southern Wisconsin (not mapped separately), red to pink alkali-feldspar granophyric granite associated with rhyolites of both peraluminous and metaluminous affinities (unit Xr of Marshfield terrane).

Migmatitic gneiss and amphibolite (Late to Early Archean) (Archean) at surface, covers 2 % of this area

Varied gneisses of mostly unknown age in cores of gneiss domes and fault-bounded uplifts (Archean gneiss terranes). Except for the Watersmeet dome (Late to Early Archean), all dated rocks are Late Archean. Includes granite of Late Archean age that transgresses gneisses and amphibolite.

Metagabbro (Early Proterozoic) at surface, covers 2 % of this area

Mafic to ultramafic bodies defined and delineated principally by positive magnetic and gravity anomalies; includes diorite bodies. Comagmatic with unit Xmi

Quartz diorite (Early Proterozoic) at surface, covers 0.7 % of this area

Includes Marinette Quartz Diorite of Dunbar Dome (Sims and others, 1985a) and nearby Twelve Foot Falls Quartz Diorite