St. Peter Sandstone
North American geological formation
title: "St. Peter Sandstone" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["ordovician-system-of-north-america", "sandstone-formations-of-the-united-states", "ordovician-arkansas", "ordovician-illinois", "ordovician-iowa", "ordovician-minnesota", "ordovician-missouri", "ordovician-south-dakota", "ordovician-wisconsin", "ordovician-nebraska"] description: "North American geological formation" topic_path: "geography/united-states" source: "https://en.wikipedia.org/wiki/St._Peter_Sandstone" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary North American geological formation ::
::data[format=table title="Infobox rockunit"]
| Field | Value |
|---|---|
| name | St. Peter Sandstone |
| image | St Peters Sandstone Pacific MO 5-med.jpg |
| caption | Old mine entrances in the St. Peter Sandstone formation in Pacific, Missouri, where it is still actively quarried nearby. |
| type | Formation |
| age | Middle Ordovician |
| period | Middle Ordovician |
| namedfor | St. Peters River (now Minnesota River), Minnesota |
| namedby | David Dale Owen |
| region | Midwest |
| country | United States |
| unitof | Ancell Group |
| underlies | Dutchtown Formation, Glenwood Shale, Joachim Dolomite, and Wells Creek Formation |
| overlies | Beekmantown Dolomite, Everton Formation, Shakopee Dolomite |
| extent | Arkansas, Illinois, Indiana, Iowa, Minnesota, Missouri, Wisconsin and West Virginia |
| :: |
| name = St. Peter Sandstone | image = St Peters Sandstone Pacific MO 5-med.jpg | caption = Old mine entrances in the St. Peter Sandstone formation in Pacific, Missouri, where it is still actively quarried nearby. | type = Formation | age = Middle Ordovician | period = Middle Ordovician | prilithology = | otherlithology = | namedfor = St. Peters River (now Minnesota River), Minnesota | namedby = David Dale Owen | region = Midwest | country = United States | coordinates = | unitof = Ancell Group | subunits = | underlies = Dutchtown Formation, Glenwood Shale, Joachim Dolomite, and Wells Creek Formation | overlies = Beekmantown Dolomite, Everton Formation, Shakopee Dolomite | thickness = | extent = Arkansas, Illinois, Indiana, Iowa, Minnesota, Missouri, Wisconsin and West Virginia | area = | map = | map_caption =
Outcrop
In Minnesota, the soft St. Peter Sandstone can be observed at the bluffs of the Mississippi River valley beneath a very thin layer of Glenwood Shale and a much thicker layer of Platteville limestone. Examples can be seen in the Mississippi River Gorge and at Minnehaha Falls in Minneapolis, the bluffs from downtown to Mounds Park in Saint Paul, and Minneopa Falls near Mankato. In Illinois, Castle Rock is a large bluff of St. Peter Sandstone, and Starved Rock State Park and Matthiessen State Park feature numerous outcroppings and canyons.
Commercial use
St. Peter sandstone, also called "Ottawa Sand" in commercial applications, has a relatively uniform size and shape for each grain. It is used for the manufacture of glass, for filter and molding sand, and for abrasives. Its purity is especially important to glassmakers.
It is also important, as proppant otherwise known as frac sand in oil and gas drilling – In Garnavillo, Iowa, Northeast Iowa the Pattson sand company has been mining the sand and shipping it to the fracking areas of the US via rail cars. loose sand pumped in a liquid mix under high pressure into a well where the sand grains wedge into and hold open any fractures in the rock, enhancing the extraction of hydrocarbons. The uniform particle size also makes the sand useful for laboratory experiments.
Mining locations
St. Peter sandstone is or has been mined
- Arkansas: Guion, Arkansas
- Illinois: Ottawa, Illinois, Sheridan, Illinois, Wedron, Illinois, Oregon, Illinois, and Naplate, Illinois
- Minnesota: Kasota, Minnesota and Ottawa Township, Minnesota
- Missouri: Pacific, Festus, Crystal City, Augusta, and Pevely
- Garnavillo, Iowa
The Unimin Corporation is a large producer of commercial sand and operates surface mines in many of these locations.
Notes
References
- Unklesbay, A.G; & Vineyard, Jerry D. (1992). Missouri Geology – Three Billion Years of Volcanoes, Seas, Sediments, and Erosion. University of Missouri Press. .
- Void ratio of sand Argonne National Laboratory, Division of Educational Program
- Twin Cities Geology - Mississippi National River and Recreation Area. National Park Service
- Generalized Stratigraphic Column of West Virginia
References
- (1847). "Preliminary report containing oulines of the progress of the geological survey of Wisconsin and Iowa, up to October 11, 1847". U.S. 30th Congress, 1st Session, Senate Executive Document Serial Set.
- Owen, D.D., 1847, Preliminary report of the geological survey of Wisconsin and Iowa: U.S. Gen. Land Office Rept., 1847, p. 160-173.
- (1934). "Type Paleozoic Sections in the Minnesota Valley". The Journal of Geology.
- Mossler, J. and Benson, S., 1995, 1999, 2006, [https://web.archive.org/web/20170712030525/ftp://mgssun6.mngs.umn.edu/pub2/mnglance/.%2FMn_Fossils.pdf Fossil Collecting in the Twin Cities Area]. Minnesota at a Glance: Minnesota Geological Survey: University of Minnesota.
- "Proppants".
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