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

Geologic units in Grant county, Wisconsin

[Additional scientific data in this geographic area]

Cambrian, undivided (Cambrian) at surface, covers 8 % 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

Maquoketa Formation (Ordovician) at surface, covers 2 % of this area

Maquoketa Formation - Shale, dolomitic shale and dolomite; includes overlying Neda Formation (age uncertain) consisting of oolitic iron oxides and shale

Lithology: shale; dolostone (dolomite)

Prairie du Chien Formation (Phanerozoic | Paleozoic | Ordovician-Early [Beekmantown]) at surface, covers 0.2 % of this area

Sandy dolomite in upper postion; sandstone in middle portion; dolomite with oolitic and tripolitic chert in lower portion.

Lithology: dolostone (dolomite); sandstone; chert

St. Peter Sandstone (Phanerozoic | Paleozoic | Ordovician-Early [Chazyan]) at surface, covers < 0.1 % of this area

Coarse to fine, rounded, frosted sand grains; minor green shale stringers.

Lithology: sandstone; shale

Silurian, undivided (Silurian) at surface, covers 0.2 % of this area

Silurian, undivided - Dolomite, undivided; includes Cayugan, Niagaran, and Alexandrian series

Lithology: dolostone (dolomite)

Prairie du Chien Group (Ordovician) at surface, covers 14 % of this area

Prairie du Chien Group - Dolomite with some sandstone and shale; includes Shakopee and Oneota Formations

Lithology: dolostone (dolomite); sandstone; shale

Ancell Group (Ordovician) at surface, covers 23 % of this area

Ancell Group - Orthoquartzitic sandstone with minor limestone, shale and conglomerate; includes Glenwood and St. Peter Formations

Lithology: sandstone; limestone; shale; conglomerate

Sinnipee Group (Ordovician) at surface, covers 53 % of this area

Sinnipee Group - Dolomite with some limestone and shale; includes Galena, Decorah, and Platteville Formations

Lithology: dolostone (dolomite); limestone; shale

Galena-Decorah-Platteville Formations (Phanerozoic | Paleozoic | Ordovician-Middle [Mohawkian]) at surface, covers < 0.1 % of this area

Galena FM- dolomite, minor limestone; chert in lower half. Approx thickness 230 ft. Decorah FM- brown limestone and dolomite; gray-green and brown shales at top and base. Approx thickness 60 ft. Platteville FM- fossiliferous gray limestone and brown dolomite; grayish-green shale at base (Glenwood). Fine- to medium-grained sandstone occurs above the Glenwood in the subsurface of southeastern Iowa. Approx thickness 110 ft

Lithology: dolostone (dolomite); limestone; shale; sandstone; chert