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Osage Series

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.
State Iowa
Name Osage Series
Geologic age Phanerozoic | Paleozoic | Carboniferous Mississippian-Early
Comments Approx total thickness 275 ft
Primary rock type dolostone (dolomite)
Secondary rock type limestone
Other rock types shale; chert; sandstone
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Carbonate > Dolostone (Bed)
Minor
Sedimentary > Clastic > Sandstone (Bed)
Incidental
Sedimentary > Chemical > Chert (Bed)
Map references
Hershey H. G. 1969, Geologic Map of Iowa: Iowa Geological Survey, scale 1:500K
Unit references
Hershey H. G. 1969, Geologic Map of Iowa: Iowa Geological Survey, scale 1:500K
Counties Boone - Dallas - Des Moines - Grundy - Hamilton - Hardin - Henry - Humboldt - Jasper - Jefferson - Johnson - Lee - Marshall - Story - Tama - Van Buren - Wapello - Washington - Webster - Wright