- St. Peter Sandstone
St. Peter sandstone is an
Ordovician formation in the Chazyan stage of the Champlainian series. Thissandstone originated as a sheet ofsand in clear, shallow water near the shore of aPaleozoic sea and consists of fine-to-medium-size, well-roundedquartz grains with frosted surfaces. The extent of the formation spans north-south fromMinnesota toMissouri and east-west fromIllinois intoNebraska andSouth Dakota . The type locality for the formation isSt. Peter, Minnesota . In eastern Missouri the stone consists of quartz sand that is 99.44% silica.Layer
In Minnesota, the soft St. Peter Sandstone can be observed at the bluffs of the Mississippi River valley beneath a layer of Platteville
limestone . Examples can be seen at theMinnehaha Falls near Minneapolis and Minneopa Falls near Mankato.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 forabrasive s. Its purity is especially important to glassmakers. It is also important as a "frac sand" in oil and gas drilling – loose sand is pumped in a liquid mix under high pressure into an 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
*
Illinois :Ottawa, Illinois
*Minnesota :Kasota, Minnesota andOttawa Township, Minnesota
*Missouri : Pacific, Festus, Crystal City, Augusta, and PevelyThe
Unimin corporation is a large producer of commercial sand and operates the surface mines in many of these locations.References
* Unklesbay, A.G; & Vineyard, Jerry D. (1992). Missouri Geology – Three Billion Years of Volcanoes, Seas, Sediments, and Erosion. University of Missouri Press. ISBN 0-8262-0836-3.
* [http://www.newton.dep.anl.gov/askasci/env99/env156.htm Void ratio of sand] Argonne National Laboratory, Division of Educational Program
* [http://www.nps.gov/archive/miss/features/geology/geology.html Twin Cities Geology - Mississippi National River and Recreation Area] . National Park Service
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