Shawnee Group

Interval includes Oread, Kanwaka, Lecompton, Tecumseh, Deer Creek, Calhoun, Topeka formations. Primary Lithologies: limestone, fossiliferous, part coated grain/Osagia; shale/mudstone, light to dark gray. Secondary Lithologies: pedogenic mudstone, part calcareous/nodular; siltstone to very fine sandstone; black shale, phosphatic. Minor: chert; coal, coaly shale; red-brown mudstone. Maximum thicknesses 190-220 ft (58-67 m).
State Iowa
Name Shawnee Group
Geologic age Upper Pennsylvanian, lower-middle Virgilian
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)fossiliferous, part coated grain/Osagia
Sedimentary > Clastic > Mudstone > Shale (Bed, Calcareous)light to dark gray; minor pedogenic mudstone, part calcareous/nodular; incidental coaly shale
Minor
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)phosphatic
Sedimentary > Clastic > Siltstone (Bed)siltstone to very fine sandstone
Incidental
Sedimentary > Coal (Bed)
Sedimentary > Chemical > Chert (Bed)
Sedimentary > Clastic > Mudstone (Bed)red-brown
References

Witzke, Brian J., Anderson, Raymond R., and Pope, John P., 2010, Iowa Geological and Water Survey, DNR, Bedrock Geologic Map of Iowa, OFM-2010-1. Scale 1:500,000.

NGMDB product
Counties Adair - Adams - Cass - Fremont - Mills - Montgomery - Page - Pottawattamie - Taylor - Union