State | Iowa |
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Name | Augusta Group |
Geologic age | Middle Mississippian, Osagean |
Lithologic constituents |
Major
Sedimentary > Carbonate > Limestone (Bed)dolomitic, fossiliferous; fossiliferous, (especially crinoidal packstone-grainstone); minor glauconitic limestone/dolomite
Sedimentary > Carbonate > Dolostone (Bed)part argillaceous to shaly; incidental phosphatic dolomite/limestone (“bone bed”)
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)gray to green-gray, part dolomitic, part silty
Sedimentary > Chemical > Chert (Bed)nodular to bedded; in northern Iowa - dolomite/chert breccia
Incidental
Sedimentary > Clastic > Siltstone (Bed)dolomitic
|
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 | Boone - Calhoun - Davis - Des Moines - Grundy - Hamilton - Hardin - Henry - Humboldt - Ida - Iowa - Jasper - Jefferson - Johnson - Keokuk - Lee - Louisa - Mahaska - Marion - Marshall - Monona - Polk - Poweshiek - Sac - Story - Tama - Van Buren - Washington - Webster - Woodbury - Wright |