The St. Peter Sandstone is an

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

. It belongs to the Chazyan stage of the Champlainian series in North American regional

stratigraphy Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...

, equivalent to the late Darriwilian global stage. This

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

originated as a sheet of

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

in clear, shallow water near the shore of a

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

sea and consists of fine-to-medium-size, well-rounded

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

grains with frosted surfaces. The extent of the formation spans north–south from

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

and east–west from

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

into

Nebraska Nebraska ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Ka ...

and

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...

. The formation was named by

David Dale Owen David Dale Owen (24 June 1807 – 13 November 1860) was a prominent American geologist who conducted the first geological surveys of Indiana, Kentucky, Arkansas, Wisconsin, Iowa and Minnesota. Owen served as the first state geologist for three sta ...

(1847) after the

Minnesota River The Minnesota River () is a tributary of the Mississippi River, approximately 332 miles (534 km) long, in the U.S. state of Minnesota. It drains a watershed of in Minnesota and about in South Dakota and Iowa. It rises in southwestern ...

, then known as the St. Peter River. The type locality is at the confluence of the

Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...

and Minnesota Rivers near

Fort Snelling Fort Snelling is a former military fortification and National Historic Landmark in the U.S. state of Minnesota on the bluffs overlooking the confluence of the Minnesota and Mississippi Rivers. The military site was initially named Fort Saint An ...

, Minnesota. In eastern Missouri, the stone consists of quartz sand that is 99.44% silica.

Outcrop

, 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 The Platteville Limestone is the Ordovician limestone formation in the sedimentary sequence characteristic of the Upper Midwest, upper Midwestern United States. It is characterized by its gray color, rough texture, and numerous fossils. Its type ...

.Mossler, J. and Benson, S., 1995, 1999, 2006
Fossil Collecting in the Twin Cities Area
Minnesota at a Glance: Minnesota Geological Survey: University of Minnesota. Examples can be seen in the Mississippi River Gorge and at

Minnehaha Falls Minnehaha Park is a city park in Minneapolis, Minnesota, United States, and home to Minnehaha Falls and the lower reaches of Minnehaha Creek. Officially named Minnehaha Regional Park, it is part of the Minneapolis Park and Recreation Board sy ...

Minneapolis Minneapolis is a city in Hennepin County, Minnesota, United States, and its county seat. With a population of 429,954 as of the 2020 United States census, 2020 census, it is the state's List of cities in Minnesota, most populous city. Locat ...

, the bluffs from downtown to Mounds Park in

Saint Paul Paul, also named Saul of Tarsus, commonly known as Paul the Apostle and Saint Paul, was a Christian apostle ( AD) who spread the teachings of Jesus in the first-century world. For his contributions towards the New Testament, he is generally ...

, and Minneopa Falls near

Mankato Mankato ( ) is a city in Blue Earth, Nicollet, and Le Sueur counties in the U.S. state of Minnesota. It is the county seat of Blue Earth County, Minnesota. The population was 44,488 at the 2020 census, making it the 21st-largest city in Mi ...

. In Illinois, Castle Rock is a large bluff of St. Peter Sandstone, and

Starved Rock State Park Starved Rock State Park is a state park in the U.S. state of Illinois, characterized by the many canyons within its . Located just southeast of the village of Utica, Illinois, Utica, in Deer Park Township, LaSalle County, Illinois, Deer Park To ...

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 Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...

, for filter and molding sand, and for

abrasive An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflec ...

s. Its purity is especially important to glassmakers. It is also important, as proppant otherwise known as frac sand in

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturate ...

and

gas Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...

drilling Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross section (geometry), cross-section in solid materials. The drill bit is usually a rotary Cutting tool (machining), cutting tool, often multi-point. The bit i ...

– 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 A well is an excavation or structure created on the earth by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...

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 *

: Guion, Arkansas *

Ottawa, Illinois Ottawa is a city in LaSalle County, Illinois, United States, and its county seat. It is located at the confluence of the navigable Fox River (Illinois River tributary), Fox River and Illinois River, the latter being a conduit for river barges and ...

Sheridan, Illinois Sheridan is a village in LaSalle County, Illinois, United States. As of the 2020 census, the village's population was 2,431, up from 2,137 at the 2010 census. It is part of the Ottawa Micropolitan Statistical Area. Geography According to th ...

, Wedron, Illinois, Oregon, Illinois, and Naplate, Illinois *

: Kasota, Minnesota and Ottawa Township, Minnesota *

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

, 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

National Park Service
Generalized Stratigraphic Column of West Virginia
{{Authority control 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