Sioux Quartzite
Encyclopedia
Proterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
that is found in region around the intersection of Minnesota, South Dakota, and Iowa, and correlates with other rock units throughout the upper midwestern
Upper Midwest
The Upper Midwest is a region in the northern portion of the U.S. Census Bureau's Midwestern United States. It is largely a sub-region of the midwest. Although there are no uniformly agreed-upon boundaries, the region is most commonly used to refer to the states of Minnesota, Wisconsin, and...
and southwestern
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...
United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It was formed by braided river
Braided river
A braided river is one of a number of channel types and has a channel that consists of a network of small channels separated by small and often temporary islands called braid bars or, in British usage, aits or eyots. Braided streams occur in rivers with high slope and/or large sediment load...
deposits, and its correlative units are thought to possibly define a large sedimentary wedge that once covered the passive margin on the then-southern side of the North American craton. In human history, it provided the catlinite
Catlinite
Catlinite is a type of argillite , usually brownish-red in color, which occurs in a matrix of Sioux quartzite. Because it is fine-grained and easily worked, it is prized by Native Americans for use in making sacred pipes such as calumets and chanunpas...
, or pipestone, that was used by the Plains Indians
Plains Indians
The Plains Indians are the Indigenous peoples who live on the plains and rolling hills of the Great Plains of North America. Their colorful equestrian culture and resistance to White domination have made the Plains Indians an archetype in literature and art for American Indians everywhere.Plains...
to carve ceremonial pipes. With the arrival of Europeans, it was heavily quarried for building stone, and was used in many prominent structures in Sioux Falls, South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
.
Geology
The Sioux Quartzite is a red to pink ProterozoicProterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
. It is a thick stratigraphic unit (~3000 m) that crops out in southwestern Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, southeastern and south-central South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
, northwestern Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
, and a small part of northeastern Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....
. It is correlated with other sandstone and quartzite units across Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
(at Rib Mountain
Rib Mountain
Rib Mountain is a glacially-eroded monadnock in central Wisconsin, located in the Town of Rib Mountain in Marathon County...
, Baraboo, Barron
Barron, Wisconsin
Barron is a city in Barron County , in the U.S. state of Wisconsin. The population was 3,248 at the 2000 census...
, Waterloo, and Flambeau
Flambeau, Wisconsin
Flambeau is the name of some places in the U.S. state of Wisconsin:*Flambeau, Price County, Wisconsin*Flambeau, Rusk County, Wisconsin...
), southeastern Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
, southern Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....
, and north-central New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
and southeast-central Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
(Ortega, Mazatzal, and Deadman Quartzite).
Its age is constrained to be between 2280 ± 110 Ma (mega annum - million years ago) from the Uranium-Lead dating
Radiometric dating
Radiometric dating is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates...
of a rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
that underlies it in northwestern Iowa, and 1120 Ma from a Potassium-Argon
Radiometric dating
Radiometric dating is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates...
date of deformation of the Sioux Quartzite in Pipestone, Minnesota
Pipestone, Minnesota
As of the census of 2000, there were 4,280 people, 1,900 households, and 1,138 families residing in the city. The population density was 1,090.8 people per square mile . There were 2,097 housing units at an average density of 534.4 per square mile...
. Its age can be better-constrained by extrapolation correlative units to between 1760 ± 10 Ma. and 1640 ± 40 Ma This period in which The Sioux Quartzite and its correlative units were deposited is known as the Baraboo interval, in which high relative sea levels covered a large amount of North America.
The Sioux quartzite was primarily formed by braided river
Braided river
A braided river is one of a number of channel types and has a channel that consists of a network of small channels separated by small and often temporary islands called braid bars or, in British usage, aits or eyots. Braided streams occur in rivers with high slope and/or large sediment load...
deposits, of quartz arenite composition, with 95% of the rock being composed of rounded, fine to medium (0.125–0.5 mm) sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
-size quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
grains
Particle size (grain size)
Particle size, also called grain size, refers to the diameter of individual grains of sediment, or the lithified particles in clastic rocks. The term may also be applied to other granular materials. This is different from the crystallite size, which is the size of a single crystal inside the...
. The rivers are believed to flow southeast, at a relatively shallow gradient. Its basal conglomerate is thought to be braided stream deposits that are more proximal to the source, and there is possible marine influence on the upper part of the unit - this interpretation is supported by evidence of marine sediments (shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
s and banded iron formation
Banded iron formation
Banded iron formations are distinctive units of sedimentary rock that are almost always of Precambrian age. A typical BIF consists of repeated, thin layers of iron oxides, either magnetite or hematite , alternating with bands of iron-poor shale and chert...
s) atop its correlative unit in Baraboo, Wisconsin. In addition, the unit contains ~1 meter beds of claystone
Claystone
Claystone is a geological term used to describe a clastic sedimentary rock that is composed primarily of clay-sized particles ....
, which are known as Catlinite
Catlinite
Catlinite is a type of argillite , usually brownish-red in color, which occurs in a matrix of Sioux quartzite. Because it is fine-grained and easily worked, it is prized by Native Americans for use in making sacred pipes such as calumets and chanunpas...
or Pipestone
Catlinite
Catlinite is a type of argillite , usually brownish-red in color, which occurs in a matrix of Sioux quartzite. Because it is fine-grained and easily worked, it is prized by Native Americans for use in making sacred pipes such as calumets and chanunpas...
, because these beds were used by the natives of the area to carve pipe bowls. It is thought that the Sioux Quartzite and its correlative units are parts of a once-laterally-extensive sedimentary wedge that covered the then-southern passive margin of the North American craton.
The Sioux Quartzite is extremely resistant to erosion, and has formed a topographic high through most of Phanerozoic
Phanerozoic
The Phanerozoic Eon is the current eon in the geologic timescale, and the one during which abundant animal life has existed. It covers roughly 542 million years and goes back to the time when diverse hard-shelled animals first appeared...
time. It was inundated by Phanerozoic seas during the periods of maximum sea level, and subsequent erosion removed these sedimentary units. For this reason, the only geologic units to sit atop the Sioux Quartzite are of Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
age, deposited when a large portion of North America was covered by the Cretaceous Interior Seaway.
Many present-day outcrops of Sioux Quartzite were exposed by glacial erosion during the Quaternary. Some of these have been dated with the cosmogenic radionuclides beryllium-10
Beryllium-10
Beryllium-10 is a radioactive isotope of beryllium. It is formed mainly by cosmic ray spallation. Be-10 has a half-life of 1.36 × 106 years, and decays by beta decay to stable Boron-10 with a maximum energy of 556.2 keV....
and aluminum-26 to determine how long ago the Laurentide Ice Sheet
Laurentide ice sheet
The Laurentide Ice Sheet was a massive sheet of ice that covered hundreds of thousands of square miles, including most of Canada and a large portion of the northern United States, multiple times during Quaternary glacial epochs. It last covered most of northern North America between c. 95,000 and...
retreated from the Upper Midwest
Upper Midwest
The Upper Midwest is a region in the northern portion of the U.S. Census Bureau's Midwestern United States. It is largely a sub-region of the midwest. Although there are no uniformly agreed-upon boundaries, the region is most commonly used to refer to the states of Minnesota, Wisconsin, and...
. These dates show that southwestern Minnesota was last covered in glacial ice at least 500,000 years ago.