The geology of Kansas encompasses the

geologic history The geological history of Earth follows the major geological events in Earth's past based on the geologic time scale, a system of chronological dating, chronological measurement based on the study of the planet's rock layers (stratigraphy). Ear ...

and the presently exposed

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wale ...

and

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

. Rock that crops out in the US state of

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

was formed during the

Phanerozoic eon The Phanerozoic is the current and the latest of the four geologic eons in the Earth's geologic time scale, covering the time period from 538.8 million years ago to the present. It is the eon during which abundant animal and plant life has ...

, which consists of three geologic eras: the

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 ...

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

and

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

. Paleozoic rocks at the surface in Kansas are primarily from the

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago * Mississippian cultures, a network of precontact cultures across the midwest and Easte ...

Pennsylvanian Pennsylvanian may refer to: * A person or thing from Pennsylvania * Pennsylvanian (geology) The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, on the International Commission on Stratigraphy, ICS geologic timesc ...

, and

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

periods.

Paleozoic Era

The oldest rocks at the surface in Kansas are Mississippian rocks that consist of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

, dolomite,

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

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 ...

s, and

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

s. The Mississippian consisted of an environment similar to present. Fast-moving streams and rivers cut into the limestone bedrock, and in some places, create caverns and

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...

s.Buchanan, R., ''Kansas Geology: An Introduction to Landscapes, Rock, Minerals, and Fossils,'' University Press of Kansas, 1984, Ch 1, p. 10 ff Pennsylvanian rocks consist predominantly of alternating marine and non-marine shales and limestones with some sandstone,

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

, chert, and conglomerate. The Pennsylvanian was a time when the region that is now eastern Kansas stayed nearly at sea level. Between the transgression and regression of the seas, swamps, and bogs formed, depositing dead vegetation and later, after burial under younger sediments, this dead vegetation formed into coal. Permian rocks predominantly consist of limestones, shales, and

evaporite An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as oce ...

s. The Permian in Kansas began as an environment consisting of warm, shallow seas. As the Permian progressed, the climate became very dry and the seas began to subside, creating bodies of water shut off from the open seas, in turn creating areas for the generation of dark shales and evaporite minerals such as

halite Halite ( ), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pi ...

and

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate Hydrate, dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk ...

as the waters evaporated. The end of the Permian marks the largest extinction period in Earth's history; over 90% of all life disappeared.

Mesozoic Era

Mesozoic rocks at the surface of Kansas consist predominantly of rocks from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

. A relatively small outcrop of

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

sediments is exposed in the southwest corner of the state. Cretaceous age rocks consist of

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Ch ...

, shale, and sandstone. The Cretaceous in Kansas was an open ocean or sea environment dominated by microscopic marine plants and animals that floated or swam near the surface of this ancient water body. As these microscopic creatures died, they sank to the bottom, formed a soft, limy ooze, and would preserve any larger creatures that died and sank into it.

Cenozoic Era

Cenozoic rocks at the surface were formed during the

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

Neogene The Neogene ( ,) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period million years ago. It is the second period of th ...

, and

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

periods. Paleogene to Neogene rocks in Kansas consist of river silt, sand, freshwater limestones, and some

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

derived from eruptions in the western United States. Near the beginning of the Paleogene, the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

were formed, as were the streams and rivers heading eastward out from the mountains into Kansas. Over 60 million years of

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

, the Rocky Mountains created a wedge of material extending to the

Flint Hills The Flint Hills, historically known as Bluestem Pastures or Blue Stem Hills, are a region of hills and prairies that lie mostly in eastern Kansas. It is named for the abundant residual flint eroded from the bedrock that lies near or at the surfa ...

of eastern Kansas. Quaternary rocks in Kansas consist of these:

glacial drift In geology, drift is a name for all sediment (clay, silt, sand, gravel, boulders) transported by a glacier and deposited directly by or from the ice, or by glacial meltwater. Drift is often subdivided into unstratified (unsorted) drift ( glac ...

; river silt, sand, and gravel;

dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

sand; and wind-blown silt. The Quaternary Period in western Kansas was very similar to the Neogene, continual erosion of the Rocky Mountains deposited additional sediments.

Physiographic regions

Kansas has been divided into eleven different

physiographic Physical geography (also known as physiography) is one of the three main branches of geography. Physical geography is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere, h ...

regions.

Ozark plateau

Mississippian limestones and cherts of the Ozark Plateau are exposed in extreme southeastern Kansas in Cherokee County. This area was part of the

Tri-state district The Tri-State district was a historic lead-zinc mining district located in present-day southwest Missouri, southeast Kansas and northeast Oklahoma. The district produced lead and zinc for over 100 years. Production began in the 1850s and 1860s ...

of the nineteenth and twentieth centuries.

Galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crysta ...

was a center of

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

and

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...

in the area.

Cherokee lowlands

The Cherokee lowlands is a region of southeast Kansas immediately north and west of the Ozark plateau in Cherokee, Labette, Crawford and Bourbon Counties. The lowlands are developed on areas of gently rolling hills developed on the shale and sandstone of the Cherokee Group of the Pennsylvanian age. The Cherokee Group is noted for rich deposits of coal in Kansas and across the midwestern United States.

Osage Cuestas

The Osage cuesta region underlies twenty counties in southeastern Kansas. The

cuesta A cuesta () is a hill or ridge with a gentle slope on one side, and a steep slope on the other. In geology, the term is more specifically applied to a ridge where a harder sedimentary rock overlies a softer layer, the whole being tilted somew ...

s are a region of east to southeast facing

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. Due to the similarity, the term '' scarp'' may mistakenly be incorrectly used inte ...

s ( high) formed on resistant limestone units which dip gently to the west and northwest. Areas between escarpments are underlain by shales. The cuesta region contains coal, black shale and some

oil shale Oil shale is an organic-rich Granularity, fine-grained sedimentary rock containing kerogen (a solid mixture of Organic compound, organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general compos ...

Lamproite Lamproite is an ultrapotassic mantle-derived volcanic or subvolcanic rock. It has low CaO, Al2O3, Na2O, high K2O/Al2O3, a relatively high MgO content and extreme enrichment in incompatible elements. Lamproites are geographically widespre ...

sills occur within the cuesta units of Woodson and Wilson counties. These unusual

igneous rock Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...

s were intruded in the Cretaceous Period.

Chautauqua Hills

The Chautauqua Hills represent a narrow region in southeast Kansas of sandstone-capped ridges and rolling hills. The Pennsylvanian age sandstones were deposited in a large river valley. The sandstones are the Tonganoxie Sandstone Member of the Stranger Formation and the Ireland Sandstone Member of the Lawrence Formation. The hills occur in the western portions of Montgomery, Wilson and Woodson counties and the eastern edges of

Chautauqua Chautauqua ( ) is an adult education and social movement in the United States that peaked in popularity in the late 19th and early 20th centuries. Chautauqua assemblies expanded and spread throughout rural America until the mid-1920s. The Cha ...

Elk The elk (: ''elk'' or ''elks''; ''Cervus canadensis'') or wapiti, is the second largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. ...

and Greenwood counties. The sandstones continue into northern Oklahoma.

Flint Hills

The Flint Hills developed on the north–south exposure of Permian

y limestones. The region extends from Marshall County in the north, to Cowley County and on into northern Oklahoma where they are known as the

Osage Hills The Osage Hills is a hilly area in Oklahoma, commonly known as ''The Osage''. The name refers to the broad rolling hills and rolling tallgrass prairie and Cross Timbers encompassing Osage County and surrounding areas, including portions of May ...

. The Permian limestones contain abundant

weathering Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...

resistant chert (or flint) and the residuum and soils of the hilltops and the streambeds of the region contain abundant cherty gravels. Surface exposures of the rare igneous

kimberlite Kimberlite is an igneous rock and a rare variant of peridotite. It is most commonly known as the main host matrix for diamonds. It is named after the town of Kimberley, Northern Cape, Kimberley in South Africa, where the discovery of an 83.5-Car ...

s occur in

Riley Riley may refer to: Businesses * Riley (brand), British sporting goods brand founded in 1878 * Riley Motor, British motorcar and bicycle manufacturera 1890–1969 * Riley Technologies, American auto racing constructor and team, founded by Bob ...

and Marshall counties. The kimberlite

diatreme A diatreme, sometimes known as a maar-diatreme volcano, is a volcanic pipe associated with a gaseous explosion. When magma rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater, rapid expansion of heated ...

s are of Cretaceous age. No diamonds have been found in the Kansas kimberlite occurrences.

Garnet Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnet minerals, while sharing similar physical and crystallographic properties, exhibit a wide range of chemical compositions, de ...

crystals from the kimberlites have been reported in local stream gravels.

Red Hills

The Red Hills cover a section of southern Kansas in

Clark Clark is an English language surname with historical links to England, Scotland, and Ireland, ultimately derived from the Latin ''clericus'' meaning "scribe", "secretary" or a scholar within a religious order, referring to someone who was educated ...

Comanche The Comanche (), or Nʉmʉnʉʉ (, 'the people'), are a Tribe (Native American), Native American tribe from the Great Plains, Southern Plains of the present-day United States. Comanche people today belong to the List of federally recognized tri ...

, and Barber counties along the Oklahoma border. The Red Hills are named for their color derived from the Permian

red bed Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone, siltstone, and shale, that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain t ...

s which outcrop and underlie the region. The red color is produced by abundant

iron oxide An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust. Iron ...

s in the weathering sediments. The region is underlain by red shales, siltstones, and sandstones along with interbedded dolomites and

layers. Massive gypsum deposits are mined near Sun City in northwestern Barber County. The Gyp Hills near Medicine Lodge were named for the gypsum of the Blaine Formation. The soluble gypsum,

anhydrite Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the ...

and dolomite produce many

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

s in the area. The Big Basin of

Clark County Clark County may refer to: *Clark County, Arkansas *Clark County, Idaho *Clark County, Illinois *Clark County, Indiana *Clark County, Kansas *Clark County, Kentucky *Clark County, Missouri *Clark County, Nevada, containing Las Vegas *Clark County, ...

is a diameter, deep, dissolution collapse feature that formed by the dissolution of salt beds in the subsurface.

Smoky Hills

The Smoky Hills constitute a large area of north central Kansas. The area is underlain by Cretaceous sediments. Rocks outcropping in the area include the sandstones of the

Dakota Formation The Dakota is a sedimentary rock, sedimentary geologic unit name of Formation (stratigraphy), formation and Group (stratigraphy), group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and ...

, the

Greenhorn Limestone The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States, dating to the Cenomanian and Turonian ages of the Late Cretaceous period. The formation gives its name to the Greenhorn cycle ...

, and the thick

Niobrara Chalk The Niobrara Formation , also called the Niobrara Chalk, is a Formation (stratigraphy), geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the La ...

. Stratigraphically the Dakota is overlain by the Greenhorn and that by the Niobrara. The Dakota outcrops in the eastern portion of the region as gently westward dipping resistant ridges. Although the sandstones are the most resistant and therefore most prominent the Dakota includes shales and clays. The formation contains abundant brown iron oxides and many

concretion A concretion is a hard and compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes a ...

s are found in the area. In the western portions of the area, the bedrock is

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

iferous

of the Niobrara Formation which includes the

Smoky Hill Chalk The Smoky Hill Chalk Member of the Niobrara Chalk formation is a Cretaceous conservation Lagerstätte, or fossil rich geological member, known primarily for its exceptionally well-preserved marine reptiles. Named for the Smoky Hill River, the S ...

member noted for abundant fish and

marine reptile Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including mari ...

fossils.

High Plains

The western third of Kansas is in the High Plains area. The highest point in Kansas, Mount Sunflower (), is located in the High Plains physiographic region. The

tectonic uplift Tectonic uplift is the orogeny, geologic uplift of Earth#Surface, Earth's surface that is attributed to plate tectonics. While Isostasy, isostatic response is important, an increase in the mean elevation of a region can only occur in response to ...

of the

during the

resulted in erosion and deposition of vast quantities of non-marine sediments eastward across the High Plains. The

Ogallala Formation The Ogallala Formation is a Miocene to early Pliocene geologic formation in the central High Plains of the western United States and the location of the Ogallala Aquifer. In Nebraska and South Dakota it is also classified as the Ogallala Group ...

consists of a large wedge of unconsolidated sands and silts that is a significant

aquifer An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...

under the plains. The Ogallala contains a sandstone layer cemented with

opal Opal is a hydrated amorphous form of silicon dioxide, silica (SiO2·''n''H2O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a ...

. In the southwest corner of the state in Morton County rocks of

age outcrop along the Cimarron River.

Loess A loess (, ; from ) is a clastic rock, clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loesses or similar deposition (geology), deposits. A loess ...

deposits cover much of the High Plains in north and northwest Kansas.

Glaciated Region

The northeast corner of the state, north of the

Kansas River The Kansas River, also known as the Kaw, is a meandering river in northeastern Kansas in the United States. It is potentially the southwestern most part of the Missouri River drainage, which is sometimes in turn the northwesternmost portion of ...

and east of the Big Blue River, is covered by

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

debris deposited during the Pre-Illinoian glaciations which occurred 600,000 years ago in the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

. The Pennsylvanian and Permian bedrock is buried under thick deposits of glacial debris, largely loess. A variety of

glacial erratic A glacial erratic is a glacially deposited rock (geology), rock differing from the type of country rock (geology), rock native to the area in which it rests. Erratics, which take their name from the Latin word ' ("to wander"), are carried by gla ...

s were left by the melting glaciers. Many of these are of

Sioux Quartzite The Sioux Quartzite is a Proterozoic quartzite that is found in the region around the intersection of Minnesota, South Dakota, and Iowa, and correlates with other rock units throughout the Upper Midwest, upper midwestern and Southwestern United ...

carried south from the

Sioux Falls, South Dakota Sioux Falls ( ) is the List of cities in South Dakota, most populous city in the U.S. state of South Dakota and the List of United States cities by population, 117th-most populous city in the United States. It is the county seat of Minnehaha Coun ...

area.

Wellington-McPherson Lowlands

The Wellington-McPherson Lowlands of south-central Kansas in

Sumner Sumner may refer to: Places Antarctica * Mount Sumner, a mountain in the Rare Range, Antarctica * Sumner Glacier, southern Graham Land, Antarctica Australia * Sumner, Queensland, a suburb of Brisbane New Zealand * Sumner, New Zealand, a seasi ...

, Sedgwick, Harvey and McPherson counties is underlain by fluvial sediments deposited in the ancestral

Arkansas River The Arkansas River is a major tributary of the Mississippi River. It generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's source basin lies in Colorado, specifically ...

valley during the Pleistocene Epoch one to two million years ago. The sediments consist largely of sands, silts, and gravel. These include the Equus Beds Aquifer sediments, named for the Pleistocene modern horse fossils they contain. Also under this area is the Permian Hutchinson salt bed which reaches a thickness of . The area also contains inactive sand dunes.http://www.kgs.ku.edu/Extension/lowlands/lowlands.html Arkansas River Lowlands and Wellington-McPherson Lowlands

Arkansas River Lowlands

The Arkansas River Lowlands follows the course of the

through southwest and south-central Kansas. The broad floodplain contains large quantities of sand and silt carried from the Rocky Mountains by the river. A significant area of sand dunes occur on the south side of the plain formed by the prevailing winds from the glaciers to the north during the Pleistocene.

Subsurface geology

The subsurface geology of Kansas consists of several sequences of sedimentary

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

deposited on the

Pre-Cambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the ...

basement A basement is any Storey, floor of a building that is not above the grade plane. Especially in residential buildings, it often is used as a utility space for a building, where such items as the Furnace (house heating), furnace, water heating, ...

of the

North American Craton North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' ...

. Several regional subsurface structures including five

sedimentary basin Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock They form when long-term subsidence ...

s exist under Kansas. These structures are important in controlling the vast deposits of

petroleum Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...

and

natural gas Natural gas (also fossil gas, methane gas, and gas) is a naturally occurring compound of gaseous hydrocarbons, primarily methane (95%), small amounts of higher alkanes, and traces of carbon dioxide and nitrogen, hydrogen sulfide and helium ...

in the state. The Central Kansas Uplift is a broad arch in the rocks of west-central Kansas. The rock units within this arch have been major oil producers. The

Anadarko Basin The Anadarko Basin is a geologic depositional and structural basin centered in the western part of the state of Oklahoma and the Texas Panhandle, and extending into southwestern Kansas and southeastern Colorado. The basin covers an area of . By t ...

of southwest Kansas contains significant natural gas. The Sedgwick Basin, the Cherokee Basin and the Forest City Basin of south and east Kansas also produce petroleum and natural gas.

Proterozoic basement

The Nemaha uplift is a deep

fault zone In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic f ...

which runs diagonally across east Kansas and extends from just south of

Omaha, Nebraska Omaha ( ) is the List of cities in Nebraska, most populous city in the U.S. state of Nebraska. It is located in the Midwestern United States along the Missouri River, about north of the mouth of the Platte River. The nation's List of United S ...

Oklahoma City Oklahoma City (), officially the City of Oklahoma City, and often shortened to OKC, is the List of capitals in the United States, capital and List of municipalities in Oklahoma, most populous city of the U.S. state of Oklahoma. The county seat ...

. This fault zone directly overlies a

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

"high" in the Precambrian basement and is structurally active as the Humboldt Fault. Some fifty miles to the west the southernmost extension of the

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

Midcontinent Rift System The Midcontinent Rift System (MRS) or Keweenawan Rift is a long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton, b ...

extends into northeastern Kansas. The northern two-thirds of Kansas is underlain by a Proterozoic sequence known as the Central Plains Orogen. The igneous and metamorphic rocks of this orogenic zone are considered to be an extension of the 1.7 Ga fold belt exposed in Colorado and Wyoming.P. K. Sims and Z. E. Petermar, ''Early Proterozoic Central Plains orogen: A major buried structure in the north-central United States,'' Geology 1986;14;488-491 The southern approximately one-third of the state is underlain by the Southern granite-rhyolite province dating to 1.35 to 1.48 Ga.Ben A. Van der Pluijm, Paul A. Catacosinos, ''Basement and basins of eastern North America,'' Geological Society of America, Special Paper 308, 1996, p. 14

References

External links

Kansas Geological Survey
{{Geology of the United States by political division

Natural history of Kansas