Nebraska /nᵻˈbræskə/ is a state that lies in both the Great Plains and the Midwestern United States. Its area is just over 77,220 sq mi with almost 1.9 million people and its largest city is Omaha, which is on the Missouri River. The state is crossed by many trails and was explored by the Lewis. Nebraska was admitted as the 37th state of the United States in 1867 and it is the only state in the United States whose legislature is unicameral and officially nonpartisan. Nebraska is composed of two major regions, the Dissected Till Plains and the Great Plains. The Dissected Till Plains is a region of rolling hills. The Great Plains occupy most of western Nebraska, characterized by treeless prairie, the state has a large agriculture sector and is a major producer of beef, pork and soybeans. Two major climatic zones are represented in Nebraska, the half of the state has a humid continental climate, and the western half. Indigenous peoples lived in the region of present-day Nebraska for thousands of years before European exploration.
The historic tribes in the state included the Omaha, Ponca, Otoe, when European exploration and settlement began, both Spain and France sought to control the region. In the 1690s, Spain established trade connections with the Apaches, by 1703, France had developed a regular trade with the native peoples along the Missouri River in Nebraska, and by 1719 had signed treaties with several of these peoples. After war broke out between the two countries, Spain dispatched an expedition to Nebraska under Lieutenant General Pedro de Villasur in 1720. The party was attacked and destroyed near present-day Columbus by a force of Pawnees and Otoes. The massacre of the Villasur expedition effectively put an end to Spanish exploration of Nebraska for the remainder of the 18th century, in 1762, during the Seven Years War, France ceded the Louisiana territory to Spain. Frances withdrawal from the area left Britain and Spain competing for dominance along the Mississippi, by 1773, that year, Mackays party built a trading post, dubbed Fort Carlos IV, near present-day Homer.
In 1819, the United States established Fort Atkinson as the first U. S. Army post west of the Missouri River, the army abandoned the fort in 1827 as migration moved further west. European-American settlement did not begin in any numbers until after 1848, on May 30,1854, the US Congress created the Kansas and the Nebraska territories, divided by the Parallel 40° North, under the Kansas–Nebraska Act. The Nebraska Territory included parts of the current states of Colorado, North Dakota, South Dakota, the territorial capital of Nebraska was Omaha
Dinosaurs are a diverse group of reptiles of the clade Dinosauria that first appeared during the Triassic. Although the exact origin and timing of the evolution of dinosaurs is the subject of active research and they became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201 million years ago. Their dominance continued through the Jurassic and Cretaceous periods and ended when the Cretaceous–Paleogene extinction event led to the extinction of most dinosaur groups 66 million years ago, until the late 20th century, all groups of dinosaurs were believed to be extinct. As such, birds were the dinosaur lineage to survive the mass extinction event. This article deals primarily with non-avian dinosaurs, Dinosaurs are a varied group of animals from taxonomic and ecological standpoints. Birds, at over 10,000 living species, are the most diverse group of vertebrates besides perciform fish, using fossil evidence, paleontologists have identified over 500 distinct genera and more than 1,000 different species of non-avian dinosaurs.
Dinosaurs are represented on every continent by both extant species and fossil remains, while dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, evidence suggests that egg laying and nest building are additional traits shared by all dinosaurs.7 meters and heights of 18 meters and were the largest land animals of all time. Still, the idea that dinosaurs were uniformly gigantic is a misconception based in part on preservation bias, as large. Many dinosaurs were small, for example, was only about 50 cm long. Through the first half of the 20th century, before birds were recognized to be dinosaurs, most of the community believed dinosaurs to have been sluggish. Most research conducted since the 1970s, has indicated that all dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction.
The large sizes of some groups, as well as their seemingly monstrous and fantastic nature, have ensured dinosaurs regular appearance in best-selling books and films. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, the term is derived from the Greek words δεινός and σαῦρος. Though the taxonomic name has often interpreted as a reference to dinosaurs teeth, claws. Instead, like many forms of reptile sub-groups, did not exhibit characteristics which were traditionally regarded as reptilian. Under phylogenetic nomenclature, dinosaurs are usually defined as the group consisting of Triceratops, their most recent common ancestor, Birds are now recognized as being the sole surviving lineage of theropod dinosaurs. In traditional taxonomy, birds were considered a class that had evolved from dinosaurs
Algae is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as Chlorella and the diatoms, to forms, such as the giant kelp. Most are aquatic and autotrophic and lack many of the cell and tissue types, such as stomata and phloem. No definition of algae is generally accepted, one definition is that algae have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. Some authors exclude all prokaryotes thus do not consider cyanobacteria as algae, Algae constitute a polyphyletic group since they do not include a common ancestor, and although their plastids seem to have a single origin, from cyanobacteria, they were acquired in different ways. Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria and brown algae are examples of algae with secondary chloroplasts derived from an endosymbiotic red alga.
Algae exhibit a range of reproductive strategies, from simple asexual cell division to complex forms of sexual reproduction. Algae lack the various structures that characterize land plants, such as the phyllids of bryophytes, rhizoids in nonvascular plants, and the roots and other organs found in tracheophytes. Most are phototrophic, although some are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some other heterotrophic organisms, such as the apicomplexans, are derived from cells whose ancestors possessed plastids. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago, the singular alga is the Latin word for seaweed and retains that meaning in English. Although some speculate that it is related to Latin algēre, be cold, a more likely source is alliga, entwining. The Ancient Greek word for seaweed was φῦκος, which could mean either the seaweed or a red dye derived from it, the Latinization, fūcus, meant primarily the cosmetic rouge.
It could be any color, red, accordingly, the modern study of marine and freshwater algae is called either phycology or algology, depending on whether the Greek or Latin root is used. The name Fucus appears in a number of taxa, most algae contain chloroplasts that are similar in structure to cyanobacteria. Chloroplasts contain circular DNA like that in cyanobacteria and presumably represent reduced endosymbiotic cyanobacteria, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting their acquisition during different endosymbiotic events. The table below describes the composition of the three groups of algae. Their lineage relationships are shown in the figure in the upper right, many of these groups contain some members that are no longer photosynthetic
Clay is a fine-grained natural rock or soil material that combines one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are plastic due to water content and become hard, brittle. Depending on the content in which it is found, clay can appear in various colours from white to dull grey or brown to deep orange-red. Although many naturally occurring deposits include both silts and clay, clays are distinguished from other fine-grained soils by differences in size, which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. There is, some overlap in size and other physical properties. The distinction between silt and clay varies by discipline and soil scientists usually consider the separation to occur at a particle size of 2 µm, sedimentologists often use 4–5 μm, and colloid chemists use 1 μm.
Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils Atterberg limits, ISO14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. These solvents, usually acidic, migrate through the rock after leaching through upper weathered layers. In addition to the process, some clay minerals are formed through hydrothermal activity. There are two types of deposits and secondary. Primary clays form as residual deposits in soil and remain at the site of formation, secondary clays are clays that have been transported from their original location by water erosion and deposited in a new sedimentary deposit. Clay deposits are associated with very low energy depositional environments such as large lakes. Depending on the source, there are three or four main groups of clays, montmorillonite-smectite and chlorite. Chlorites are not always considered to be a clay, sometimes being classified as a group within the phyllosilicates.
There are approximately 30 different types of clays in these categories. Varve is clay with visible annual layers, which are formed by deposition of those layers and are marked by differences in erosion. This type of deposit is common in glacial lakes
A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi in a symbiotic relationship. The combined lichen has properties different from those of its component organisms, Lichens come in many colours and forms. The properties are sometimes plant-like, but lichens are not plants, Lichens may have tiny, leafless branches, flat leaf-like structures, flakes that lie on the surface like peeling paint, or other growth forms. A macrolichen is a lichen that is either bush-like or leafy, here and micro do not refer to size, but to the growth form. Common names for lichens may contain the word moss, and lichens may superficially look like and grow with mosses, Lichens do not have roots that absorb water and nutrients as plants do, but like plants, they produce their own food by photosynthesis. When they grow on plants, they do not live as parasites, Lichens occur from sea level to high alpine elevations, in many environmental conditions, and can grow on almost any surface.
Lichens are abundant growing on bark, mosses, on other lichens and they grow on rock, gravestones, exposed soil surfaces, and in the soil as part of a biological soil crust. Different kinds of lichens have adapted to survive in some of the most extreme environments on Earth, arctic tundra, hot dry deserts, rocky coasts and they can even live inside solid rock, growing between the grains. It is estimated that 6% of Earths land surface is covered by lichen, there are about 20,000 known species of lichens. Some lichens have lost the ability to reproduce sexually, yet continue to speciate, Lichens may be long-lived, with some considered to be among the oldest living things. They are among the first living things to grow on fresh rock exposed after an event such as a landslide, the long life-span and slow and regular growth rate of some lichens can be used to date events. In American English, lichen is pronounced the same as the verb liken, in British English, both this pronunciation and one rhyming with kitchen /ˈlɪtʃən/) are used.
Lichens grow in a range of shapes and forms. The shape of a lichen is determined by the organization of the fungal filaments. The nonreproductive tissues, or vegetative body parts, is called the thallus, Lichens are grouped by thallus type, since the thallus is usually the most visually prominent part of the lichen. Thallus growth forms typically correspond to a few basic internal structure types, Common names for lichens often come from a growth form or color that is typical of a lichen genus. When a crustose lichen gets old, the center may start to crack up like old-dried paint, old-broken asphalt paving and this is called being rimose or areolate, and the island pieces separated by the cracks are called areolas. The areolas appear separated, but are connected by an underlying prothallus or hypothallus, when a crustose lichen grows from a center and appears to radiate out, it is called crustose placodioid
Dinosaur National Monument
Dinosaur National Monument is a U. S. National Monument located on the southeast flank of the Uinta Mountains on the border between Colorado and Utah at the confluence of the Green and Yampa Rivers. Although most of the monument area is in Moffat County, the nearest communities are Jensen and Dinosaur, Colorado. This park contains over 800 paleontological sites and has fossils of dinosaurs including Allosaurus, Deinonychus and various long-neck and it was declared a National Monument on October 4,1915. The rock layer enclosing the fossils is a sandstone and conglomerate bed of alluvial or river bed known as the Morrison Formation from the Jurassic Period some 150 million years old. The dinosaurs and other ancient animals were carried by the system which eventually entombed their remains. The pile of sediments were buried and lithified into solid rock. The layers of rock were uplifted and tilted to their present angle by the mountain building forces that formed the Uintas during the Laramide orogeny, the relentless forces of erosion exposed the layers at the surface to be found by paleontologists.
The dinosaur fossil beds were discovered in 1909 by Earl Douglass and he and his crews excavated thousands of fossils and shipped them back to the museum in Pittsburgh, Pennsylvania for study and display. President Woodrow Wilson proclaimed the dinosaur beds as Dinosaur National Monument in 1915, though lesser-known than the fossil beds, the petroglyphs in Dinosaur National Monument are another treasure the monument holds. Due to problems with vandals, many of the sites are not listed on area maps, the controversy assumed major proportions, dominating conservation politics for years. They argued that, if a national monument was not safe from development, after much debate, Congress settled on a compromise that eliminated Echo Park Dam and authorized the rest of the project. The Colorado River Storage Project Act became law on April 11,1956. It stated, “that no dam or reservoir constructed under the authorization of the Act shall be within any National Park or Monument. ”Historians view the Echo Park Dam controversy as signaling the start of an era that includes major conservationist political successes such as the Wilderness Act and the Wild and Scenic Rivers Act.
Mantles Cave is a prehistoric Fremont culture residential site from 499 BC - AD1749, typical of high deserts, summer temperatures can be exceedingly hot, while winter temperatures can be very cold. Snowfall is common, but the snow melts rapidly in the arid, rainfall is very low, and the evaporation rate classifies the area as desert, even though the rainfall just barely exceeds 10 inches. The Wall of Bones located within the Dinosaur Quarry building in the consists of a steeply tilted rock layer which contains hundreds of dinosaur fossils. The enclosing rock has been chipped away to reveal the fossil bones intact for public viewing, in July 2006, the Quarry Visitor Center was closed due to structural problems that since 1957 had plagued the building because it was built on unstable clay. It was announced in April 2009 that Dinosaur National Monument would receive $13.1 million to refurbish, the Park Service successfully rebuilt the Quarry Exhibit Hall, supporting its weight on 70-foot steel micropile columns that extend to the bedrock below the unstable clay
Wyoming /waɪˈoʊmɪŋ/ is a state in the mountain region of the western United States. The state is the tenth largest by area, the least populous, Wyoming is bordered on the north by Montana, on the east by South Dakota and Nebraska, on the south by Colorado, on the southwest by Utah, and on the west by Idaho. Cheyenne is the capital and the most populous city in Wyoming, the state population was estimated at 586,107 in 2015, which is less than the population of 31 of the largest U. S. cities. The Crow, Arapaho and Shoshone were some of the inhabitants of the region. Southwestern Wyoming was included in the Spanish Empire and Mexican territory until it was ceded to the United States in 1848 at the end of the Mexican–American War. The region acquired the name Wyoming when a bill was introduced to Congress in 1865 to provide a government for the territory of Wyoming. The territory was named after the Wyoming Valley in Pennsylvania, with the name ultimately being derived from the Munsee word xwé, wamənk, the mineral extraction industry—especially coal, natural gas, and trona—along with the travel and tourism sector are the main drivers behind Wyomings economy.
Agriculture has historically been an important component of the economy with the main commodities being livestock, sugar beets, grain. The climate is generally semi-arid and continental, being drier and windier in comparison to the rest of the United States, except for the 1964 election, Wyoming has been a politically conservative state since the 1950s, with the Republican party winning every presidential election. Wyoming is one of three states to have borders along only straight latitudinal and longitudinal lines, rather than being defined by natural landmarks. Wyoming is bordered on the north by Montana, on the east by South Dakota and Nebraska, on the south by Colorado, on the southwest by Utah, and on the west by Idaho. It is the tenth largest state in the United States in total area, from the north border to the south border it is 276 miles, and from the east to the west border is 365 miles at its south end and 342 miles at the north end. The Great Plains meet the Rocky Mountains in Wyoming, the state is a great plateau broken by many mountain ranges.
Surface elevations range from the summit of Gannett Peak in the Wind River Mountain Range, at 13,804 feet, to the Belle Fourche River valley in the states northeast corner, at 3,125 feet. In the northwest are the Absaroka, Owl Creek, Gros Ventre, Wind River, in the north central are the Big Horn Mountains, in the northeast, the Black Hills, and in the southern region the Laramie and Sierra Madre ranges. The Snowy Range in the central part of the state is an extension of the Colorado Rockies in both geology and appearance. The Wind River Range in the west central part of the state is remote and includes more than 40 mountain peaks in excess of 13,000 ft tall in addition to Gannett Peak, the highest peak in the state. The Big Horn Mountains in the central portion are somewhat isolated from the bulk of the Rocky Mountains
The Navajo are a Native American people of the Southwestern United States. After the Cherokee, they are the second-largest federally recognized tribe in the United States, the Navajo language is spoken throughout the region, with most Navajos speaking English, as well. The states with the largest Navajo populations are Arizona and New Mexico, over three-quarters of the Navajo population reside in these two states. The Navajos are speakers of a Na-Dené Southern Athabaskan language known within the language as Diné bizaad, the language comprises two geographic, mutually intelligible dialects. It is closely related to the Apache language, as the Navajos and Apaches are believed to have migrated from northwestern Canada and eastern Alaska, speakers of various other Athabaskan languages located in Canada may still comprehend the Navajo language despite the geographic and linguistic deviation of the languages. Additionally, some Navajos speak Navajo Sign Language, which is either a dialect or daughter of Plains Sign Talk and historical evidence suggests the Athabaskan ancestors of the Navajos and Apaches entered the Southwest around 1400 CE.
The Navajo oral tradition is said to retain references of this migration, until contact with Pueblos and the Spanish, the Navajos were largely hunters and gatherers. The tribe adopted crop-farming techniques from the Pueblo peoples, growing corn, beans. When the Spanish arrived, the Navajos began herding sheep and goats as a source of trade and food. Sheep became a form of currency and status symbols among the Navajos based on the quantity of herds a family maintained. In addition, the practice of spinning and weaving wool into blankets and clothing became common, in the 18th century, the Spanish reported the Navajos maintaining large herds of livestock and cultivating large crop areas. Navahu comes from the Tewa, meaning area of cultivated lands. By the 1640s, the Spanish began using the term Navajo to refer to the Diné, during the 1670s, the Spanish wrote that the Diné lived in a region known as Dinétah, about 60 miles west of the Rio Chama valley region. In the 1780s, the Spanish sent military expeditions against the Navajos in the Mount Taylor, the Navajos came into contact with the United States Army in 1846, when General Stephen W.
Kearny invaded Santa Fe with 1,600 men during the Mexican–American War. The treaty was not honored by many young Navajo raiders, who continued to steal livestock from New Mexican villages, New Mexicans, on their part, together with Utes, continued to raid Navajo country, stealing livestock and taking women and children for sale as slaves. In 1849, the governor of New Mexico, Colonel John MacRae Washington—accompanied by John S. The treaty acknowledged the jurisdiction of the United States and allowed forts, the United States, on its part, promised such donations such other liberal and humane measures, as may deem meet and proper. While en route to this treaty signing, Narbona, a prominent Navajo peace leader, was killed, during the next 10 years, the U. S. established forts on traditional Navajo territory
Badlands National Park
The park is managed by the National Park Service. Authorized as Badlands National Monument on March 4,1929, it was not established until January 25,1939 and it was redesignated a national park on November 10,1978. Under the Mission 66 plan, the Ben Reifel Visitor Center was constructed for the monument in 1957–58, the park administers the nearby Minuteman Missile National Historic Site. Long before the Lakota were the little-studied paleo-Indians, followed by the Arikara people and their descendants live today in North Dakota as a part of the Three Affiliated Tribes. Archaeological records combined with oral traditions indicate that these people camped in secluded valleys where fresh water and game were available year round. Eroding out of the stream banks today are the rocks and charcoal of their campfires, as well as the arrowheads and tools used to butcher bison, rabbits. From the top of the Badlands Wall, they could scan the area for enemies, if hunting was good, they might hang on into winter, before retracing their way to their villages along the Missouri River.
By one hundred and fifty years ago, the Great Sioux Nation consisting of seven including the Oglala Lakota, had displaced the other tribes from the northern prairie. The next great change came toward the end of the 19th century as homesteaders moved into South Dakota, the U. S. government stripped Native Americans of much of their territory and forced them to live on reservations. In the fall and early winter of 1890, thousands of Native American followers, including many Oglala Sioux and his vision called for the native people to dance the Ghost Dance and wear Ghost shirts, which would be impervious to bullets. Wovoka had predicted that the man would vanish and their hunting grounds would be restored. One of the last known Ghost Dances was conducted on Stronghold Table in the South Unit of Badlands National Park, as winter closed in, the ghost dancers returned to Pine Ridge Agency. The climax of the came in late December,1890. Headed south from the Cheyenne River, a band of Minneconjou Sioux crossed a pass in the Badlands Wall, pursued by units of the U. S.
Army, they were seeking refuge in the Pine Ridge Reservation. The band, led by Chief Spotted Elk, was overtaken by the soldiers near Wounded Knee Creek in the Reservation. The troops attempted to disarm Big Foots band the next morning, before it was over, nearly three hundred Indians and thirty soldiers lay dead. Wounded Knee is not within the boundaries of Badlands National Park and it is located approximately 45 miles south of the park on Pine Ridge Reservation. The U. S. government and the Oglala Lakota Nation have agreed that this is a story to be told by the Oglala of Pine Ridge, the interpretation of the site and its tragic events are held as the primary responsibility of these survivors
Theodore Roosevelt National Park
Theodore Roosevelt National Park is a United States National Park comprising three geographically separated areas of badlands in western North Dakota. The park was named for U. S. President Theodore Roosevelt, the park covers 70,446 acres of land in three sections, the North Unit, the South Unit, and the Elkhorn Ranch Unit. The parks larger South Unit lies alongside Interstate 94 near Medora, the smaller North Unit is situated about 80 mi north of the South Unit, on U. S. Highway 85, just south of Watford City, North Dakota. Roosevelts Elkhorn Ranch is located between the North and South units, approximately 20 mi west of US85 and Fairfield, the Little Missouri River flows through all three units of the park. The Maah Daah Hey Trail connects all three units, the park received 753,880 recreational visitors in 2016, which is an increase of 30% from the prior year. Roosevelt first came to the North Dakota badlands to hunt bison in September 1883, during that first short trip, he got his bison and fell in love with the rugged lifestyle and the perfect freedom of the West.
He invested $14,000 in the Maltese Cross Ranch, which was already being managed by Sylvane Ferris and that winter and Merrifield built the Maltese Cross Cabin. After the death of both his wife and his mother on February 14,1884, Teddy Roosevelt returned to his North Dakota ranch seeking solitude and time to heal. That summer, he started his second ranch, the Elkhorn Ranch,35 miles north of Medora, Teddy Roosevelt took great interest in his ranches and in hunting in the West, detailing his experiences in pieces published in eastern newspapers and magazines. He wrote three works on his life in the West, Ranch Life and the Hunting Trail, Hunting Trips of a Ranchman. Following Theodore Roosevelts death in 1919, the Little Missouri Badlands were explored to determine possible park sites, civilian Conservation Corps camps were established in both of the future park units from 1934 to 1941, and they developed roads and other structures in use today. The area was designated the Roosevelt Recreation Demonstration Area in 1935, in 1946 it was transferred to the United States Fish and Wildlife Service as the Theodore Roosevelt National Wildlife Refuge.
President Truman established the Theodore Roosevelt National Memorial Park on April 25,1947, in 1978, in addition to boundary adjustments and the establishment of 29,920 acres of the Theodore Roosevelt Wilderness, the parks designation was changed to Theodore Roosevelt National Park. Both main units of the park have scenic drives, approximately 100 miles of foot and horse trails, wildlife viewing, and opportunities for back country hiking and camping. There are three developed campgrounds, Juniper Campground in the North Unit, Cottonwood Campground in the South Unit, one of the most popular attractions is wildlife viewing. Bison may be dangerous and visitors are advised to them from a distance. Bison and bighorn sheep have been reintroduced to the park. The scenery changes constantly in relationship with the seasons, the brown, dormant grass dominates from late summer through the winter, but explodes into green color in the early summer along with hundreds of species of flowering plants
The Eocene Epoch, lasting from 56 to 33.9 million years ago, is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. As with other periods, the strata that define the start and end of the epoch are well identified. The name Eocene comes from the Ancient Greek ἠώς and καινός, the Eocene epoch is conventionally divided into early and late subdivisions. The corresponding rocks are referred to as lower, the Ypresian stage constitutes the lower, the Priabonian stage the upper, and the Lutetian and Bartonian stages are united as the middle Eocene. The Eocene Epoch contained a variety of different climate conditions that includes the warmest climate in the Cenozoic Era.
During this period of time, little to no ice was present on Earth with a difference in temperature from the equator to the poles. Following the maximum was a descent into an icehouse climate from the Eocene Optimum to the Eocene-Oligocene transition at 34 million years ago. During this decrease ice began to reappear at the poles, greenhouse gases, in particular carbon dioxide and methane, played a significant role during the Eocene in controlling the surface temperature. For the early Eocene there is discussion on how much carbon dioxide was in the atmosphere. This is due to numerous proxies representing different atmospheric carbon dioxide content, for contrast, today the carbon dioxide levels are at 400 ppm or 0. 04%. At about the beginning of the Eocene Epoch the amount of oxygen in the atmosphere more or less doubled. During the early Eocene, methane was another gas that had a drastic effect on the climate. In comparison to carbon dioxide, methane has much effect on temperature as methane is ~34 times more effective per molecule than carbon dioxide on a 100-year scale.
Most of the methane released to the atmosphere during this period of time would have been from wetlands, the atmospheric methane concentration today is 0. 000179% or 1.79 ppmv. Due to the climate and sea level rise associated with the early Eocene, more wetlands, more forests. Comparing the early Eocene production of methane to current levels of atmospheric methane, biogenic production of methane produces carbon dioxide and water vapor along with the methane, as well as yielding infrared radiation
Scoria is a highly vesicular, dark colored volcanic rock that may or may not contain crystals. It is typically dark in color, and basaltic or andesitic in composition, Scoria is relatively low in density as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity greater than 1, and sinks in water. Scoria may form as part of a flow, typically near its surface, or as fragmental ejecta. Most scoria is composed of fragments, and may contain phenocrysts. The word scoria comes from the Greek σκωρία, skōria, rust, an old name for scoria is cinder. Scoria differs from pumice, another vesicular volcanic rock, in having larger vesicles and thicker vesicle walls, the difference is probably the result of lower magma viscosity, allowing rapid volatile diffusion, bubble growth and bursting. As rising magma encounters lower pressures, dissolved gases are able to exsolve, some of the vesicles are trapped when the magma chills and solidifies. Vesicles are usually small, spheroidal and do not impinge upon one another, volcanic cones of scoria can be left behind after eruptions, usually forming mountains with a crater at the summit.
An example is Maungarei in New Zealand, which like Te Tatua-a-Riukiuta in the south of the city has been extensively quarried. Quincan, a form of Scoria, is quarried at Mount Quincan in Far North Queensland. Scoria has several characteristics that influence how it is used. It is somewhat porous, has high surface area and strength for its weight, Scoria is often used in landscaping and drainage works. It is used in gas barbecue grills. Scoria can be used for high-temperature insulation, Scoria is used on oil well sites to limit mud issues with heavy truck traffic. It is used as a traction aid on ice- and snow-covered roads, cinder Tuff Pumice Volcanoes List of rock types Rock