Maquoketa Formation

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Maquoketa Formation
Stratigraphic range: Darriwilian-Hirnantian (Edenian-Richmondian)
461–444  Ma
Type Formation
Unit of Maquoketa Group
Sub-unitsBrainard, Clermont & Elgin members
Underlies Thebes Formation & Wapsipinicon Group
Overlies Cape & Dubuque Formations
Thickness10–100 ft (3.0–30.5 m)
Lithology
Primary Shale, dolomite
Other Limestone, phosphorite
Location
Coordinates 42°30′N91°18′W / 42.5°N 91.3°W / 42.5; -91.3
Approximate paleocoordinates 20°36′S63°42′W / 20.6°S 63.7°W / -20.6; -63.7
Region Minnesota, Wisconsin, Illinois, Iowa, Kentucky, Kansas
Country United States
Extent Illinois Basin
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Maquoketa Formation (the United States)
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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]

References

  1. A comparison of the Maquoketa formation and its fauna in Eastern Wisconsin, Iowa and Illinois (1915), Thesis (M.A.) The University of Illinois
  2. Maquoketa Group, Indiana Geological Survey
  3. Ordovician in Kansas
  4. Maquoketa Formation in Minnesota
  5. 1 2 The Stratigraphic Succession in Missouri, Missouri Geological Survey, Vol. XL 2nd series, 1961, pp 30-31
  6. USGS, Maquoketa Formation
  7. Maquoketa Formation at Fossilworks.org

Further reading