Niobrara Formation

Last updated
Niobrara Formation
Stratigraphic range: Coniacian–Campanian
Chalk badlands (Niobrara Formation, Upper Cretaceous; chalk bluffs south of Castle Rock, Gove County, Kansas, USA) 7 (38417957134).jpg
Smoky Hill Chalk badlands, Niobrara Formation, in Kansas
Type Formation
Sub-units Smoky Hill Chalk Member
Fort Hays Limestone Member
Underlies Pierre Shale
Overlies Carlile Formation
Or Benton Shale where the Carlile or Greenhorn Formations are not developed
Primary Chalk
Other Shale
Coordinates 42°44′49″N98°02′24″W / 42.747°N 98.040°W / 42.747; -98.040
RegionNorth America
CountryFlag of Canada (Pantone).svg  Canada
Flag of the United States.svg  United States
Type section
Named for Niobrara River, Knox Co., Nebraska [1]
Named by Meek, F.B., and Hayden, F.V.
Year defined1862
Usa edcp relief location map.png
Lightgreen pog.svg
Niobrara Formation (the United States)
USA Nebraska relief location map.svg
Lightgreen pog.svg
Niobrara Formation (Nebraska)
Monument Rocks, Smoky Hill Chalk Monument Rocks, Gove, Kansas.jpg
Monument Rocks, Smoky Hill Chalk
Cremnoceramus deformis, index fossil of the Fort Hays Limestone Member Fort Hays Limestone, Cremnoceramus deformis 20180915.jpg
Cremnoceramus deformis, index fossil of the Fort Hays Limestone Member
Niobrara Chalk, weathered and opalized in the Valentine phase of the Ogallala Niobrara, opalized, Ellis County 20180915 110441.jpg
Niobrara Chalk, weathered and opalized in the Valentine phase of the Ogallala

The Niobrara Formation /ˌn.əˈbrærə/ , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous. It is composed of two structural units, the Smoky Hill Chalk Member overlying the Fort Hays Limestone Member. The chalk formed from the accumulation of coccoliths from microorganisms living in what was once the Western Interior Seaway, an inland sea that divided the continent of North America during much of the Cretaceous. It underlies much of the Great Plains of the US and Canada. Evidence of vertebrate life is common throughout the formation and includes specimens of plesiosaurs, mosasaurs, and pterosaurs as well as several primitive aquatic birds. The type locality for the Niobrara Chalk is the Niobrara River in Knox County in northeastern Nebraska.


History of exploration

The Niobrara Chalk was recorded (1857) and named (1862) by Meek, F.B., and Hayden, F.V.. [1] It was first studied during an expedition led by Othniel Charles Marsh of Yale University in 1870. This and following expeditions to the area in 1871 and 1872 yielded the first of many fossil vertebrate remains commonly attributed with the formation. Excavations continued through the following years up to 1879 under the direction of professional fossil collectors such as B. F. Mudge and S. W. Williston appointed by Marsh.

The Niobrara Chalk has been continuously explored ever since, with specimens being found by H. T. Martin of the University of Kansas and George F. Sternberg, the son of the famous fossil collector Charles H. Sternberg. Much of the best material from the formation is on display at the Sternberg Museum of Natural History in Hays, Kansas.


The Smoky Hill Chalk Member of the Niobrara Chalk contains the majority of the fossils found in the formation, and is subdivided into 23 marker beds. Most vertebrates are present from the upper half of the member. Most of the vertebrate remains were collected and described before the stratigraphy of the Niobrara Chalk was fully understood. Specimens were described as being from layers referred to as being either of gray-blue shale or yellow chalk. This dichotomy is not indicative of different stratigraphic units as was previously thought, but rather is seen as a weathering phenomenon that can be found at varying points in the same outcrop. [2]

The Fort Hays Limestone Member consists of somewhat harder, massive limestone beds. [3]

The Niobrara Formation is overlain by the marine Pierre Shale and is underlain by the Carlile Shale or Benton Shale.

Flora and fauna

During the time of the deposition of the Niobrara Chalk, much life inhabited the seas of the Western Interior Seaway. By this time in the Late Cretaceous many new lifeforms appeared such as mosasaurs, which were to be some of the last of the aquatic lifeforms to evolve before the end of the Mesozoic. Life of the Niobrara Chalk is comparable to that of the Dakota Formation, although the Dakota Formation, which was deposited during the Cenomanian, predates the chalk by about 10 million years.

Mineral resources

Various exposures of Niobrara Chalk were covered and partially silicified as the Ogallala sediments covered the Neogene plains. Re-exposed during the Quaternary, [4] these cherty materials, known as Smoky Hill Jasper and Smoky Hill silicified chalk, or more recently as Niobrara Jasper or Niobrarite, became source material for stone tools from the earliest human habitation of the High Plains. [5] [6]

In some regions, the Niobrara is a commercial hydrocarbon reservoir. Natural gas is produced from the Niobrara in the eastern Denver Basin. Oil is produced from the Niobrara in the North Park Basin, and new fracturing methods are allowing much larger areas to be tapped for oil. [7]

The Fort Hays member was historically quarried on the High Plains for the manufacture of Portland cement at Superior, Nebraska and Yocemento, Kansas, as well as along the Dakota Hogback in Colorado from Lyons to Boulder, and around Pueblo and Florence. [8] Along the Dakota Hogback north of Laporte, Colorado, the Fort Hays Limestone formed a secondary hogback, which was extensively quarried for manufacture of up to 450,000 tons of cement a year. [9] The full depth of the Niobrara was quarried by the [[commons::File:Western Portland Cement plant (Yankton SD) stack 1.JPG|Western Portland Cement Company]] at Yankton, South Dakota, which supplied cement to the Panama Canal project. [10]

Related Research Articles

<i>Xiphactinus</i> Extinct genus of fishes

Xiphactinus is an extinct genus of large predatory marine bony fish that lived during the Late Cretaceous. When alive, the fish would have resembled a gargantuan, fanged tarpon. The species Portheus molossus described by Cope is a junior synonym of X. audax. Skeletal remains of Xiphactinus have come from the Carlile Shale and Greenhorn Limestone of Kansas, and Cretaceous formations all over the East Coast in the United States, as well as Europe, Australia, the Kanguk and Ashville Formations of Canada, La Luna Formation of Venezuela and the Salamanca Formation in Argentina.

Smoky Hills

The Smoky Hills are an upland region of hills in the central Great Plains of North America. They are located in the Midwestern United States, encompassing north-central Kansas and a small portion of south-central Nebraska.

<i>Niobrarasaurus</i> Extinct genus of reptiles

Niobrarasaurus is an extinct genus of nodosaurid ankylosaur which lived during the Cretaceous 87 to 82 million years ago. Its fossils were found in the Smoky Hill Chalk Member of the Niobrara Formation, in western Kansas, which would have been near the middle of Western Interior Sea during the Late Cretaceous. It was a nodosaurid, an ankylosaur without a clubbed tail. It was closely related to Nodosaurus.

Tylosaurinae Extinct subfamily of lizards

The Tylosaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "tylosaurines" and have been recovered from every continent except for South America. The subfamily includes the genera Tylosaurus, Taniwhasaurus, Hainosaurus and Kaikaifilu.

<i>Protosphyraena</i> Extinct genus of fishes

Protosphyraena is a fossil genus of swordfish-like marine fish, that thrived worldwide during the Upper Cretaceous Period (Coniacian-Maastrichtian). Though fossil remains of this taxon have been found in both Europe and Asia, it is perhaps best known from the Smoky Hill Member of the Niobrara Chalk Formation of Kansas. Protosphyraena was a large fish, averaging 2–3 metres in length. Protosphyraena shared the Cretaceous oceans with aquatic reptiles, such as mosasaurs and plesiosaurs, as well as with many other species of extinct predatory fish. The name Protosphyraena is a combination of the Greek word protos ("early") plus Sphyraena, the genus name for barracuda, as paleontologists initially mistook Protosphyraena for an ancestral barracuda. Recent research shows that the genus Protosphyraena is not at all related to the true swordfish-family Xiphiidae, but belongs to the extinct family Pachycormidae.

<i>Dolichorhynchops</i> Extinct genus of reptiles

Dolichorhynchops is an extinct genus of polycotylid plesiosaur from the Late Cretaceous of North America, containing three species, D. osborni, D. bonneri and D. tropicensis, as well as a questionably referred fourth species, D. herschelensis. Dolichorhynchops was an oceangoing prehistoric reptile. Its Greek generic name means "long-nosed face".

Dakota Formation

The Dakota is a sedimentary geologic unit name of formation and group rank composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway. The usage of the name Dakota for this particular Albian-Cenomanian strata is exceptionally widespread; from British Columbia and Alberta to Montana and Wisconsin to Colorado and Kansas to Utah and Arizona. It is famous for producing massive colorful rock formations in the Rocky Mountains and the Great Plains of the United States, and for preserving both dinosaur footprints and early deciduous tree leaves.

Geology of Kansas

The Geology of Kansas encompasses the geologic history of the US state of Kansas and the present-day rock and soil that is exposed there. Rock that crops out in Kansas was formed during the Phanerozoic eon, which consists of three geologic eras: the Paleozoic, Mesozoic and Cenozoic. Paleozoic rocks at the surface in Kansas are primarily from the Mississippian, Pennsylvanian and Permian periods.

<i>Toxochelys</i> Extinct genus of turtles

Toxochelys is an extinct genus of marine turtle from the Late Cretaceous period. It is the most commonly found fossilized turtle species in the Smoky Hill Chalk, in western Kansas.

Smoky Hill Chalk

The Smoky Hill Chalk Member of the Niobrara Chalk formation is a Cretaceous conservation Lagerstätte, or fossil rich geological formation, known primarily for its exceptionally well-preserved marine reptiles. Named for the Smoky Hill River, the Smoky Hill Chalk Member is the uppermost of the two structural units of the Niobrara Chalk. It is underlain by the Fort Hays Limestone Member; and the Pierre Shale overlies the Smoky Hill Chalk. The Smoky Hill Chalk outcrops in parts of northwest Kansas, its most famous localities for fossils, and in southeastern Nebraska. Large well-known fossils excavated from the Smoky Hill Chalk include marine reptiles such as plesiosaurs, large bony fish such as Xiphactinus, mosasaurs, flying reptiles or pterosaurs, flightless marine birds such as Hesperornis, and turtles. Many of the most well-known specimens of the marine reptiles were collected by dinosaur hunter Charles H. Sternberg and his son George. The son collected a unique fossil of the giant bony fish Xiphactinus audax with the skeleton of another bony fish, Gillicus arcuatus inside the larger one. Another excellent skeleton of Xiphactinus audax was collected by Edward Drinker Cope during the late nineteenth century heyday of American paleontology and its Bone Wars.

Colorado is a geologic name applied to certain rocks of Cretaceous age in the North America, particularly in the western Great Plains. This name was originally applied to classify a group of specific marine formations of shale and chalk known for their importance in Eastern Colorado. The surface outcrop of this group produces distinctive landforms bordering the Great Plains and it is a significant feature of the subsurface of the Denver Basin and the Western Canadian Sedimentary Basin. These formations record important sequences of the Western Interior Seaway, and as the geology of this seaway was studied, this name came to be used in states beyond Colorado, but was later replaced in several of these states with more localized names.

Paleobiota of the Niobrara Formation

During the time of the deposition of the Niobrara Chalk, much life inhabited the seas of the Western Interior Seaway. By this time in the Late Cretaceous many new lifeforms appeared such as mosasaurs, which were to be some of the last of the aquatic lifeforms to evolve before the end of the Mesozoic. Life of the Niobrara Chalk is comparable to that of the Dakota Formation, although the Dakota Formation, which was deposited during the Cenomanian, predates the chalk by about 10 million years.

Carlile Shale A geologic formation in the western US

The Carlile Shale is a Turonian age Upper/Late Cretaceous series shale geologic formation in the central-western United States, including in the Great Plains region of Colorado, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, and Wyoming.

Graneros Shale

The Graneros Shale is a geologic formation in the United States identified in the Great Plains as well as New Mexico that dates to the Cenomanian Age of the Cretaceous Period. It is defined as the argillaceous or clayey near-shore/marginal-marine shale that lies above the older, non-marine Dakota sand and mud, but below the younger, chalky open-marine shale of the Greenhorn. This definition was made in Colorado by G. K. Gilbert and has been adopted in other states that use Gilbert's division of the Benton's shales into Carlile, Greenhorn, and Graneros. These states include Kansas, Texas, Oklahoma, Nebraska, and New Mexico as well as corners of Minnesota and Iowa. North Dakota, South Dakota, Wyoming, and Montana have somewhat different usages — in particular, north and west of the Black Hills, the same rock and fossil layer is named Belle Fourche Shale.

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 Valentine Formation is a geologic unit formation or member within the Ogallala unit in northcentral Nebraska near the South Dakota border. It preserves fossils dating to the Neogene period and is particularly noted for Canid fossils. A particular feature of the Valentine is lenticular beds of green-gray opaline sandstone that can be identified in other states, including South Dakota, Nebraska, Kansas, and Colorado. Even though three mammalian fauna stages can be mapped throughout the range of the Ogallala, no beddings of the Ogallala are mappable and all attempts of formally applying the Valentine to any mappable lithology beyond the type location have been abandoned. Even so, opaline sandstone has been used to refer to the green-gray opalized conglomerate sandstone that is a particular feature of the lower Ogallala.

Timeline of mosasaur research

This timeline of mosasaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of mosasaurs, a group of giant marine lizards that lived during the Late Cretaceous Epoch. Although mosasaurs went extinct millions of years before humans evolved, humans have coexisted with mosasaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about warfare between serpentine water monsters and aerial thunderbirds told by the Native Americans of the modern western United States may have been influenced by observations of mosasaur fossils and their co-occurrence with creatures like Pteranodon and Hesperornis.

Fort Hays Limestone Member

The Fort Hays Limestone is a member of the Niobrara Formation of the Colorado Group exposed in Colorado, Kansas, Nebraska, and South Dakota and is named for the bluffs near the old Fort Hays, a well-known landmark in western Kansas.

The geology of South Dakota began to form more than 2.5 billion years ago in the Archean eon of the Precambrian. Igneous crystalline basement rock continued to emplace through the Proterozoic, interspersed with sediments and volcanic materials. Large limestone and shale deposits formed during the Paleozoic, during prevalent shallow marine conditions, followed by red beds during terrestrial conditions in the Triassic. The Western Interior Seaway flooded the region, creating vast shale, chalk and coal beds in the Cretaceous as the Laramide orogeny began to form the Rocky Mountains. The Black Hills were uplifted in the early Cenozoic, followed by long-running periods of erosion, sediment deposition and volcanic ash fall, forming the Badlands and storing marine and mammal fossils. Much of the state's landscape was reworked during several phases of glaciation in the Pleistocene. South Dakota has extensive mineral resources in the Black Hills and some oil and gas extraction in the Williston Basin. The Homestake Mine, active until 2002, was a major gold mine that reached up to 8000 feet underground and is now used for dark matter and neutrino research.

Fencepost limestone

Fencepost limestone, Post Rock limestone, or Stone Post is a stone bed in the Great Plains notable for its historic use as fencing and construction material in north-central Kansas resulting in unique cultural expression. The source of this stone is the topmost layer of the Greenhorn Limestone formation. It is a regional marker bed as well as a valued construction material of the late 19th and early 20th centuries in Kansas. This stone was very suitable for early construction in treeless settlements and it adds a notable rust orange tint to the region's many historic stone buildings. But the most famous use is seen in the countless miles of stone posts lining country roads and highways. This status gives rise to such regional appellations as Stone Post Country, Post Rock Scenic Byway, and The Post Rock Capital of Kansas. This rustic quality finds Fencepost limestone still used in Kansas landscaping today.


  1. 1 2 "Geologic Unit: Niobrara". National Geologic Database. Geolex — Significant Publications. United States Geological Survey. Retrieved 2020-06-05.
  2. Williston, S. W., 1897, The Kansas Niobrara Cretaceous: The University Geological Survey of Kansas, v. 2, p. 237–246.
  3. Howard E. Simpson. "Geology of the Yankton Area South Dakota and Nebraska" (PDF). Geological Survey Professional Paper. U.S. Department of the Interior.
  4. Alvin R. Leonard and Delmar W. Berry (1961). Geology and Ground-water Resources of Southern Ellis County and Parts of Trego and Rush Counties, Kansas, Bulletin 149. University of Kansas Publications, State Geological Survey of Kansas. p. Geomorphology / Stream Development. At the close of Pliocene time, the area from the Rocky Mountains to the Flint Hills was a nearly featureless aggradational plain crossed by streams flowing toward the east. During the formation of this [Ogallala] plain in central Kansas the Cretaceous [Niobrara] rocks were buried under a mantle of debris, ...CS1 maint: uses authors parameter (link)
  5. "Smoky Hill Jasper". Kansas Memory. Kansas Historical Society.
  6. Carl M. Wright (1985). "Complex Aspects of the "Smoky Hill Jasper", Now Known as Niobrarite".
  7. Google article
  8. Kansas Geological Survey: Fort Hays Chalk, accessed 20 January 2009.
  9. Cement plant closure opens door to uncertain future, accessed 4 July 2016.
  10. Kathy K. Grow, Lois H. Varvel. Yankton, South Dakota in Vintage Postcards. p. 24. Retrieved 2018-08-03.CS1 maint: uses authors parameter (link)

Further reading