| Maquoketa Formation | |
|---|---|
| Stratigraphic range: Darriwilian-Hirnantian (Edenian-Richmondian) | |
| Type | Formation |
| Unit of | Maquoketa Group |
| Sub-units | Brainard, Clermont & Elgin members |
| Underlies | Thebes Formation & Wapsipinicon Group |
| Overlies | Cape & Dubuque Formations |
| Thickness | 10–100 ft (3.0–30.5 m) |
| Lithology | |
| Primary | Shale, dolomite |
| Other | Limestone, phosphorite |
| Location | |
| Coordinates | 42°30′N 91°18′W / 42.5°N 91.3°W |
| Approximate paleocoordinates | 20°36′S 63°42′W / 20.6°S 63.7°W |
| Region |  Minnesota Wisconsin Illinois Iowa Kentucky Kansas |
| Country |  United States |
| Extent | Illinois Basin |
  Maquoketa Formation (the United States)  Maquoketa Formation (Iowa) | |
The Maquoketa Formation is a geologic formation in Illinois,[1] Indiana.[2] Iowa, Kansas,[3] Minnesota,[4] Missouri,[5] and Wisconsin.[6] It preserves mollusk, coral, brachiopod and graptolite fossils[5] dating back to the Darriwilian to Hirnantian stages (Edenian to Richmondian in the regional stratigraphy) of the Ordovician period.[7]
- ^ A comparison of the Maquoketa formation and its fauna in Eastern Wisconsin, Iowa and Illinois (1915), Thesis (M.A.) The University of Illinois
- ^ Maquoketa Group, Indiana Geological Survey
- ^ Ordovician in Kansas
- ^ Maquoketa Formation in Minnesota
- ^ a b The Stratigraphic Succession in Missouri, Missouri Geological Survey, Vol. XL 2nd series, 1961, pp 30-31
- ^ USGS, Maquoketa Formation
- ^ Maquoketa Formation at Fossilworks.org