Geologic units in Jackson county, Wisconsin

Additional scientific data in this geographic area

Cambrian, undivided (Cambrian) at surface, covers 97 % of this area

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

Tuff breccia schist and minor iron-formation (Late Archean) at surface, covers 1 % of this area

Pink and gray, layered quartzofeldspathic schist of intermediate volcanic composition and associated thin iron-formation. Felsic gneiss at Arbutus Dam on Black River at Hatfield has U-Pb zircon age of about 2800 Ma (Sims and others, 1989)

Gneiss, migmatite, and amphibolite (Late Archean) at surface, covers 0.8 % of this area

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)

Banded iron-formation and associated volcanogenic rocks (Late Archean) at surface, covers 0.3 % of this area

Magnetite-quartz iron-formation and associated talc schist in aluminous quartzofeldspathic schist (unit Wt)

Alkali feldspar granite of 1835 Ma age group (Early Proterozoic) at surface, covers < 0.1 % of this area

Red to pink, medium-grained leucocratic alkali feldspar granite; contains miarolitic cavities; biotite is altered to opaque oxide minerals; contains fluorite locally. Called red granite previously (Sims, 1990). Exposed in both Pembine-Wausau and Marshfield terranes.