Dubuque Formation
| Dubuque Formation | |
|---|---|
| Stratigraphic range: Ordovician | |
| Type | Formation |
| Underlies | Maquoketa Formation |
| Overlies | Galena Group |
| Location | |
| Region | Illinois, Minnesota |
| Country | United States |
The Dubuque Formation is a geologic formation in Illinois, Iowa, Wisconsin and Minnesota. It preserves fossils dating back to the Ordovician period.[1] It comprises carbonate and argillaceous rocks that are between 35 and 45 feet deep.[2]
Texture
[edit]The texture of the Dubuque formation somewhat resembles old bricks as large hard slabs of limestone are present with soft "Mortar" like rocks linking all of these slabs together. It has some fossils but a lot less than the underlieing Stewartville Formation,[3][4][5]
See also
[edit]References
[edit]- ↑ Burr, J. H., Jr.; Swain, F. M. (1965). Ostracoda of the Dubuque and Maquoketa Formations of Minnesota and Northern Iowa. Minneapolis: University Of Minnesota. p. 1-3.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ↑ Levorson, C.; Gerk, A.; Broadhead, Thomas (1 January 1979). "Stratigraphy of the Dubuque Formation (Upper Ordovician) in Iowa". Proceedings of the Iowa Academy of Science. 86 (2): 57–65. ISSN 0085-2236. Retrieved 11 June 2025.
- ↑ Forestville mystery cave state park tour
- ↑ Niagara cave tour
- ↑ Ojakangas, Richard W. Roadside geology of minnesota.
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