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White River Formation
The White River Formation is a geologic formation of the Paleogene Period, in the northern Great Plains and central Rocky Mountains, within the United States. It has been found in northeastern Colorado, Dawes County in western Nebraska, Badlands of western South Dakota, and Douglas area of southeastern Wyoming. Fossil record The geologic formation preserves fossils dating back to the Eocene and Oligocene Epochs of the Paleogene Period, during the Cenozoic Era. It contains the most complete Late Eocene−Priabonian and Early Oligocene−Rupelian vertebrate record in North America. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Badlands
Badlands are a type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded."Badlands" in '' Chambers's Encyclopædia''. London: George Newnes, 1961, Vol. 2, p. 47. They are characterized by steep slopes, minimal vegetation, lack of a substantial regolith, and high drainage density.A.J. Parsons and A.D. Abrahams, Editors (2009) ''Geomorphology of Desert Environments'' (2nd ed.) Springer Science & Business Media Ravines, gullies, buttes, hoodoos and other such geologic forms are common in badlands. Badlands are found on every continent except Antarctica, being most common where there are unconsolidated sediments. They are often difficult to navigate by foot, and are unsuitable for agriculture. Most are a result of natural processes, but destruction of vegetation by overgrazing or pollution can produce anthropogenic badlands. Badlands topography Badlands are characterized by a distinctive badlands topography. This is terrain in whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chadron Formation
Chadron Formation is a rock formation in North Dakota, South Dakota, northwestern Nebraska, and eastern Wyoming. It is named after the town of Chadron, Nebraska Chadron ( ) is a city in and the county seat of Dawes County, Nebraska, United States, in the Great Plains region. The population was 5,206 at the 2020 United States census, 2020 census. The city is home to an 11-story high-rise on the campus o .... It was mapped out by Carl Vondra in the 1950s. References Paleogene geology of North Dakota Paleogene geology of South Dakota Paleogene Colorado Paleogene geology of Nebraska Paleogene geology of Wyoming Tuff formations of the United States Sandstone formations of the United States {{NorthDakota-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Eocene
The Priabonian is, in the International Commission on Stratigraphy, ICS's geologic timescale, the latest age (geology), age or the upper stage (stratigraphy), stage of the Eocene epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between . The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage of the Oligocene. ''Priabona florissantius, Priabona'', an extinct dipteran of Pipunculidae family, is named after Priabonian, the age of deposits from which this insect is known. History and naming The Priabonian Stage was introduced in scientific literature by Ernest Munier-Chalmas and Albert de Lapparent in 1893. The stage is named after the small hamlet of Priabona (Monte di Malo), Priabona in the community of Monte di Malo, in the Veneto region of northern Italy. Stratigraphic definition The base of the Priabonian Stage is at the first appearance datum, first appearance of calcareous nannoplankton species ''Chiasmolithus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenozoic Era
The Cenozoic Era ( ; ) is Earth's current geological Era (geology), era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, Insect, insects, birds and flowering plant, angiosperms (flowering plants). It is the latest of three geological eras of the Phanerozoic Eon (geology), Eon, preceded by the Mesozoic and Paleozoic. The Cenozoic started with the Cretaceous–Paleogene extinction event, when many species, including the non-avian dinosaurs, became extinct in an event attributed by most experts to the impact of a large asteroid or other celestial body, the Chicxulub impactor. The Cenozoic is also known as the Age of Mammals because the terrestrial animals that dominated both hemispheres were mammalsthe eutherians (placentals) in the Northern Hemisphere and the metatherians (marsupials, now mainly restricted to Australia and to some extent South America) in the Southern Hemisphere. The extinction of many groups allowed mamma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (geology)
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardised international units of geological time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils
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 preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of '' Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before print. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Douglas, Wyoming
Douglas is a city in and the county seat of Converse County, Wyoming, United States. The population was 6,386 at the 2020 United States census, 2020 census. It is the home of the Wyoming State Fair. History Douglas was platted in 1886 when the Wyoming Central Railway (later the Chicago and North Western Transportation Company) established a railway station; the settlement had been in existence since 1867 when Fort Fetterman was built and was first known as "Tent City"American Automobile Association (2002) ''Tourbook: Idaho, Montana & Wyoming'' AAA Publishing, Heathrow, Florida, p. 148 ISSN 0363-2695 before it was officially named "Douglas", after Senator Stephen A. Douglas. It served as a supply point, warehousing and retail, for surrounding cattle ranches, as well as servicing railway crews, cowboys and the troops of the United States Army, U.S. Army stationed at Fort Fetterman. Douglas was the home of a Camp Douglas (Wyoming), World War II prisoner of war camp. Its former rai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Dakota Badlands
Badlands National Park () is a List of national parks of the United States, national park of the United States in southwestern South Dakota. The park protects of sharply Erosion, eroded buttes and Pinnacle (geology), pinnacles, along with the largest undisturbed mixed grass prairie in the United States. The National Park Service manages the park, with the South Unit being co-managed with the Oglala Lakota tribe. Located within the White River (Missouri River), White River drainage, the Badlands Wilderness protects of the park's North Unit as a designated wilderness area, and is one site where the black-footed ferret, one of the most Endangered species, endangered mammals in the world, was Species reintroduction, reintroduced to the wild. The South Unit, or Stronghold District, includes sites of 1890s Ghost Dances, a former United States Air Force bomb and gunnery range, and Red Shirt Table, the park's highest point at . Authorized as Badlands National Monument on March 4, 1929 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dawes County, Nebraska
Dawes County is a county in the U.S. state of Nebraska. As of the 2020 United States census, the population was 8,199. Its county seat is Chadron. The county was formed in 1885; it was named for James W. Dawes, the Nebraska Governor at the time. In the Nebraska license-plate system, Dawes County is represented by the prefix 69 (it had the 69th-largest number of vehicles registered when the license-plate system was established in 1922). History Dawes County was a part of the unorganized area of northwestern Nebraska until February 19, 1877, when it became a part of Sioux County from which it was separated February 19, 1885, and was given its present name. Geography Dawes County lies on the north border of Nebraska. Its north boundary line abuts the south boundary line of the state of South Dakota. According to the US Census Bureau, the county has an area of , of which is land and (0.3%) is water. Since it lies in the western part of Nebraska, Dawes County residents observe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Period (geology)
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardised international units of geological time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 first period of the Cenozoic Era, the tenth period of the Phanerozoic and is divided into the Paleocene, Eocene, and Oligocene epochs. The earlier term Tertiary Period was used to define the time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use. Paleogene is often abbreviated "Pg", although the United States Geological Survey uses the abbreviation "" for the Paleogene on the Survey's geologic maps. Much of the world's modern vertebrate diversity originated in a rapid surge of diversification in the early Paleogene, as survivors of the Cretaceous–Paleogene extinction event took advantage of empty ecolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (geology)
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 exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
