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

Geologic units in Van Buren county, Iowa

Cherokee Group (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Middle [Des Moines]) at surface, covers 58 % of this area

Cyclic deposits with carbonaceous shale, clay, siltstone, with lesser sandstone, and thick coal beds; minor but persistent limestone beds; may include parts of Atoka or Morrow Series.

Lithology: shale; claystone; siltstone; sandstone; coal; limestone

Meramec Series (Phanerozoic | Paleozoic | Carboniferous Mississippian-Late) at surface, covers 32 % of this area

Ste. Genevieve Limestone- fossiliferous limestone and red and green shale. Approx. thickness 50 ft. St. Louis Limestone- limestone and dolomite, sandstone locally perdominant; locally contains chert. Spergen Formation- sandy micaceous dolomite.

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

Osage Series (Phanerozoic | Paleozoic | Carboniferous Mississippian-Early) at surface, covers 10 % of this area

Warsaw Formation- gray, dolomitic shale and argillaceous dolomite; chalcedonic chert. Locally contains many geodes.Approx thickness 85 ft. Keokuk Limestone- fossiliferous, gray or brown limestone and dolomite; gray and brown chert with white spicules, locally predominant in lower portion; minor brown or gray shale. Approx thickness 90 ft. Burlington Limestone- gray, fossiliferous limestone and darker gray dolomite; white and gray mottled fossiliferous chert, locally contains dolomite crystals; two widespread glauconite zones; basal sandstone locally in southeastern Iowa. Approx thickness 80 ft.

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