Colorado is a state of the Western United States encompassing most of the southern Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. It is the 8th most extensive and 21st most populous U. S. state. The estimated population of Colorado was 5,695,564 on July 1, 2018, an increase of 13.25% since the 2010 United States Census. The state was named for the Colorado River, which early Spanish explorers named the Río Colorado for the ruddy silt the river carried from the mountains; the Territory of Colorado was organized on February 28, 1861, on August 1, 1876, U. S. President Ulysses S. Grant signed Proclamation 230 admitting Colorado to the Union as the 38th state. Colorado is nicknamed the "Centennial State" because it became a state one century after the signing of the United States Declaration of Independence. Colorado is bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, Oklahoma to the southeast, New Mexico to the south, Utah to the west, touches Arizona to the southwest at the Four Corners.
Colorado is noted for its vivid landscape of mountains, high plains, canyons, plateaus and desert lands. Colorado is part of the western and southwestern United States, is one of the Mountain States. Denver is most populous city of Colorado. Residents of the state are known as Coloradans, although the antiquated term "Coloradoan" is used. Colorado is notable for its diverse geography, which includes alpine mountains, high plains, deserts with huge sand dunes, deep canyons. In 1861, the United States Congress defined the boundaries of the new Territory of Colorado by lines of latitude and longitude, stretching from 37°N to 41°N latitude, from 102°02'48"W to 109°02'48"W longitude. After 158 years of government surveys, the borders of Colorado are now defined by 697 boundary markers and 697 straight boundary lines. Colorado and Utah are the only states that have their borders defined by straight boundary lines with no natural features; the southwest corner of Colorado is the Four Corners Monument at 36°59'56"N, 109°2'43"W.
This is the only place in the United States where four states meet: Colorado, New Mexico and Utah. The summit of Mount Elbert at 14,440 feet elevation in Lake County is the highest point in Colorado and the Rocky Mountains of North America. Colorado is the only U. S. state that lies above 1,000 meters elevation. The point where the Arikaree River flows out of Yuma County and into Cheyenne County, Kansas, is the lowest point in Colorado at 3,317 feet elevation; this point, which holds the distinction of being the highest low elevation point of any state, is higher than the high elevation points of 18 states and the District of Columbia. A little less than half of Colorado is flat and rolling land. East of the Rocky Mountains are the Colorado Eastern Plains of the High Plains, the section of the Great Plains within Nebraska at elevations ranging from 3,350 to 7,500 feet; the Colorado plains are prairies but include deciduous forests and canyons. Precipitation averages 15 to 25 inches annually. Eastern Colorado is presently farmland and rangeland, along with small farming villages and towns.
Corn, hay and oats are all typical crops. Most villages and towns in this region boast both a grain elevator. Irrigation water is available from subterranean sources. Surface water sources include the South Platte, the Arkansas River, a few other streams. Subterranean water is accessed through artesian wells. Heavy use of wells for irrigation caused underground water reserves to decline. Eastern Colorado hosts considerable livestock, such as hog farms. 70% of Colorado's population resides along the eastern edge of the Rocky Mountains in the Front Range Urban Corridor between Cheyenne and Pueblo, Colorado. This region is protected from prevailing storms that blow in from the Pacific Ocean region by the high Rockies in the middle of Colorado; the "Front Range" includes Denver, Fort Collins, Castle Rock, Colorado Springs, Pueblo and other townships and municipalities in between. On the other side of the Rockies, the significant population centers in Western Colorado are the cities of Grand Junction and Montrose.
The Continental Divide of the Americas extends along the crest of the Rocky Mountains. The area of Colorado to the west of the Continental Divide is called the Western Slope of Colorado. West of the Continental Divide, water flows to the southwest via the Colorado River and the Green River into the Gulf of California. Within the interior of the Rocky Mountains are several large parks which are high broad basins. In the north, on the east side of the Continental Divide is the North Park of Colorado; the North Park is drained by the North Platte River, which flows north into Nebraska. Just to the south of North Park, but on the western side of the Continental Divide, is the Middle Park of Colorado, drained by the Colorado River; the South Park of Colorado is the region of the headwaters of the South Platte River. In southmost Colorado is the large San Luis Valley, where the headwaters of the Rio Grande are located; the valley sits between the Sangre De Cristo Mountains and San Juan Mountains, consists of large desert lands that run into the mountains.
The Rio Grande drains due south into New Mexico and Texas. Across the Sangre de Cristo Range to the east of the S
The Book Cliffs are a series of desert mountains and cliffs in western Colorado and eastern Utah, in the western United States. They are so named because the cliffs of Cretaceous sandstone that cap many of the south-facing buttes appear similar to a shelf of books. Stretching nearly 200 miles from east to west, the Book Cliffs begin where the Colorado River descends south through De Beque Canyon into the Grand Valley to Price Canyon; the Book Cliffs appear along the southern and western edge of the Tavaputs Plateau. The cliffs are composed of sedimentary materials; the Book Cliffs are within the Colorado Plateau geologic province. In the Colorado stretch of the Book Cliffs, abandoned coal mines are present, as significant coal resources were present in the region; these mines are now capped for safety, but several fatalities of recreational hikers have occurred at these mines since 1989. In some places, "wild" horses can be found in the Book Cliffs, for example, a band of four was spotted near the abandoned Gearhart coal mine in Mesa County, Colorado.
The Book Cliffs are one of the world's best places to study sequence stratigraphy. In the 1980s, Exxon scientists used the Cretaceous strata of the Book Cliffs to develop the science of sequence stratigraphy; the Book Cliffs have preserved excellent strata of the foreland basin of the ancient Western Interior Seaway that stretched north from the Gulf of Mexico to the Yukon in the Cretaceous time. Components of deltaic and shallow marine reservoirs are well preserved in the Book Cliffs. Large mammals found in the Book Cliffs include coyotes, mountain lions, mule deer, black bears, American bison as an extension of the Henry Mountains bison herd and bighorn sheep. In January, 2009, Utah Division of Wildlife Resources officials transplanted 31 bison from the Henry Mountains bison herd to the Book Cliffs; the new group joined 14 animals released in August, 2008 from a private herd on the nearby Uintah and Ouray Indian Reservation. Since this herd is located 100 miles north of the Henry Mountains, across harsh, desert terrain, it should be considered as a separate herd, the Book Cliffs bison herd.
List of mountains in Colorado List of mountains in Utah "Book Cliffs". SummitPost.org. Cretaceous Paleogeography - Showing Western Interior Seaway The Soils of Western Colorado Mesa and Montrose Counties
Carnegie Museum of Natural History
Carnegie Museum of Natural History located at 4400 Forbes Avenue in the Oakland neighborhood of Pittsburgh, Pennsylvania, USA, was founded by the Pittsburgh-based industrialist Andrew Carnegie in 1896. It maintains an international reputation for research and is ranked among the top five natural history museums in the United States; the museum consists of 115,000 square feet organized into 20 galleries as well as research and office space. It holds some 22 million specimens, of which about 10,000 are on view at any given time and about 1 million are cataloged in online databases. In 2008 it hosted 63,000 school group visits. Museum education staff actively engage in outreach by traveling to schools all around western Pennsylvania; the museum gained prominence in 1899 when its scientists unearthed the fossils of Diplodocus carnegii. Today its dinosaur collection includes the world's largest collection of Jurassic dinosaurs and its Dinosaurs in Their Time exhibition offers the third largest collection of mounted, displayed dinosaurs in the United States.
Notable specimens include one of the world's only fossils of a juvenile Apatosaurus, the world's first specimen of a Tyrannosaurus rex, a identified species of oviraptorosaur named Anzu wyliei. Research teams including former Carnegie scientists made critical discoveries such as Puijila darwini, Castorocauda lutrasimilis, Hadrocodium wui. Other major exhibits include Hillman Hall of Minerals and Gems, Alcoa Foundation Hall of American Indians, Polar World: Wyckoff Hall of Arctic Life, Walton Hall of Ancient Egypt, Benedum Hall of Geology, Dinosaurs in Their Time, Powdermill Nature Reserve, established by the museum in 1956 to serve as a field station for long-term studies of natural populations; the museum's active curatorial departments are: Anthropology, Botany, Invertebrate Paleontology, Invertebrate Zoology, Minerals and Vertebrate Paleontology. These departments work collaboratively under strategic centers created to re-frame how the museum leverages its research and public programming to meet the challenges and issues of today.
In late 2013, the museum's parent organization and interim administration eliminated multiple scientific positions affecting its capacity to conduct original research. Carnegie Museum of Natural History publishes scholarly journals and books including Annals of Carnegie Museum, which offers peer-reviewed articles in organismal biology, earth sciences, anthropology. Carnegie Museums of Pittsburgh List of museums in Pennsylvania Andrey Avinoff Rudyerd Boulton Andrew Carnegie Benjamin Preston Clark Mary Dawson Carl H. Eigenmann Coleman J. Goin John Bell Hatcher LeRoy Kershaw Henry William Jacob Holland M. Graham Netting Arnold Edward Ortmann Kenneth C. Parkes Albert Schwartz Richard Shine James L. Swauger Walter Edmond Clyde Todd Richard Vogt Carnegie Collection Official website Carnegie Museums
The Shay locomotive was the most used geared steam locomotive. The locomotives were built to the patents of Ephraim Shay, credited with the popularization of the concept of a geared steam locomotive. Although the design of Ephraim Shay's early locomotives differed from ones, there is a clear line of development that joins all Shays. Ephraim Shay, was a schoolteacher, a clerk in a Civil War hospital, a civil servant, a logger, a merchant, a railway owner, an inventor who lived in Michigan. In the 1860s he became a logger and wanted a better way to move logs to the mill than on winter snow sleds, he built his own tramway in 1875, on 2 ft 2 in gauge track on wooden ties, allowing him to log all year round. Two years he developed the idea of having an engine sit on a flat car with a boiler and trucks that could pivot; the first Shay only had two cylinders and the front truck was mounted while the rear truck was fixed to the frame and could not swivel, much as normal drivers on a locomotive. He mounted the 3-foot diameter by 5-foot tall boiler centered on the car with the water tank over the front trucks and with an engine supplied by William Crippen mounted crossways over the rear trucks.
Shay experimented first with a chain drive from the engine through the floor to the truck axle. It is not known if he powered one or both axles, but he soon found that the chain drive was not practical and he next tried a belt drive, it did not take long for the idea to become popular. Shay applied for and was issued a patent for the basic idea in 1881, he patented an improved geared truck for his engines in 1901. Lima Locomotive Works of Lima, Ohio built Ephraim Shay's prototype engine in 1880. Prior to 1884, all the Shays Lima produced weighed 10 to 15 short tons each and had just two cylinders. In 1884, they delivered the first 3-cylinder Shay, in 1885, the first 3-truck Shay; the success of the Shay led to a major reorganization of the Lima company. When Lima first received the Shay idea it was not impressed, until John Carnes influenced the company to use the idea, resulting in the classic Shay design. In 1903, Lima could claim that it had delivered the "heaviest locomotive on drivers in the world", the first 4-truck Shay, weighing 140 short tons.
This was built for the El Paso Rock Island Line from Alamogordo, New Mexico to Cox Canyon, 31 miles away over winding curves and grades of up to 6 %. The use of a two-truck tender was necessary because the poor water quality along the line meant that the locomotive had to carry enough water for a round trip. Lewis E. Feightner, working for Lima, patented improved engine mounting brackets and a superheater for the Shay in 1908 and 1909. After the basic Shay patents had expired, Willamette Iron and Steel Works of Portland, manufactured Shay-type locomotives, in 1927, Willamette obtained a patent on an improved geared truck for such locomotives. Since "Shay" was a trademark of Lima speaking it is incorrect to refer to locomotives manufactured by Willamette and others as "Shays". Six Shay Patent locomotives, known as Henderson-style Shays, were built by the Michigan Iron Works in Cadillac, Michigan. Shay locomotives had regular fire-tube boilers offset to the left to provide space for, counterbalance the weight of, a two or three cylinder "motor," mounted vertically on the right with longitudinal drive shafts extending fore and aft from the crankshaft at wheel axle height.
These shafts had universal joints and square sliding prismatic joints to accommodate the swiveling trucks. Each axle was driven with no side rods; the strength of these engines lies in the fact that all wheels, including, in some engines, those under the tender, are driven so that all the weight develops tractive effort. A high ratio of piston strokes to wheel revolutions allowed them to run at partial slip, where a conventional rod engine would spin its drive wheels and burn rails, losing all traction. Shay locomotives were known as sidewinders or stemwinders for their side-mounted drive shafts. Most were built for use in the United States, but many were exported, to about thirty countries, either by Lima, or after they had reached the end of their usefulness in the US. 2770 Shay locomotives were built by Lima in four classes, from 6 to 160 tons, between 1878 and 1945. Class A: two cylinders, two trucks. Weight between 6 and 24 tons. Class B: three cylinders, two trucks. Weight between 10 and 80 tons.
Class C: three cylinders, three trucks. Weight between 40 and 160 tons. Class D: three cylinders, four trucks. Weight of 100 and 150 tons; these were no more powerful than Class C, but had greater fuel and water capacity, resulting in improved adhesion. Two 15 ton Shays were built with three trucks. Four Shays were built left-handed, all special ordered for the Sr. Octaviano B. Cabrera Co. San Luis de la Paz, Mexico. 118 Shays survive today, some a combination of parts of two Shays. Herewith a partial list: The Yosemite Lumber Company's #4 Shay is restored and is on continuous display at the Sierra Nevada Logging Museum in Arnold, California, it worked at the top of the El Portal Incline, bringing sugar pine logs to the top of the incline, where the loaded rail cars were lowered about 3000 feet in a mile and a half, picked up by a different railroad and taken to the mill. Restored and on continuous outdoor display in downtown Cadillac, Michigan for free viewing is a Cadillac–Soo Lumber Company locomotive with tender.
The official Michigan historical marker by it explains much. The oldest surviving Shay, serial number 122, built in 1884, is displayed in Redding California
Under the Whyte notation for the classification of steam locomotives, 0-6-2 represents the wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles and two trailing wheels on one axle. The type is sometimes known as a Branchliner. While some locomotives with this wheel arrangement had tenders, the majority were tank locomotives which carried their coal and water onboard. Finland used two classes of 0-6-2T locomotive, the Vr2 and the Vr5; the Vr2 class was numbered in the range from 950 to 965. Five of them are preserved in Finland, no. 950 at Joensuu, no. 951 at Tuuri, no. 953 at Haapamäki, no. 961 at Jyväskylä and no. 964 at the Veturimuseo at Toijala. The Vr5 class was numbered in the range from 1400 to 1423. No. 1422 is preserved at Haapamäki. Between 1890 and 1898, four 0-6-2 tender locomotives were placed in service by the Cape Copper Company on its 2 ft 6 in gauge Namaqualand Railway between Port Nolloth and O'okiep in the Cape Colony. Acquired to meet the traffic needs of the upper mountainous section of the line, they became known as the Mountain type.
The first three of these locomotives were described as the Clara Class, while the fourth was included in this Class by some and included in the subsequent Scotia Class by others. Between 1900 and 1905, six more Mountain type 0-6-2 tender locomotives were placed in service by the Cape Copper Company. Described as the Scotia Class, they were similar to the earlier Clara Class locomotives, but with longer boilers, longer fireboxes and larger firegrates. In 1892 and 1893, the Nederlandsche-Zuid-Afrikaansche Spoorweg-Maatschappij of the Zuid-Afrikaansche Republiek placed twenty 3 ft 6 in Cape gauge 0-6-2T locomotives in mainline service. Since the railway classified its locomotives according to their weight, these locomotives were known as the 40 Tonners. Three classes of 600 mm gauge 0-6-2 locomotives were supplied to German South West Africa between 1904 and 1908. In 1904, the Otavi Mining and Railway Company acquired fifteen tank locomotives from Arnold Jung Lokomotivfabrik in Germany. Two of them survived to be taken onto the South African Railways roster in 1922.
They were referred to as the Jung locomotives. Ten Class Ha tank locomotives were supplied by Henschel & Son in 1904. One survived the First World War into the SAR era. Fifteen Class Hb tank locomotives were supplied by Henschel between 1905 and 1908; the last six locomotives were delivered as tank-and-tender engines, equipped with optional coal and water tenders. Six of them survived into the SAR era. In the United Kingdom, the type was only used for tank engines and was first used by William Barton Wright of the Lancashire and Yorkshire Railway in 1880; the arrangement was soon afterwards used by F. W. Webb of the London and North Western Railway on his famous Coal Tanks of 1881-1897. Many locomotives of this type were used to haul coal in the South Wales Valleys by the Great Western Railway and its predecessors. Several railways around London used the type for heavy suburban passenger trains, notably the following: The London Brighton and South Coast Railway with the E3, E4, E5 and E6 classes designed by R. J. Billinton between 1894 and 1904.
The Great Eastern Railway Class L77 of 1914, designed by Alfred John Hill. The Great Northern Railway N1 and N2 Classes, designed by Nigel Gresley between 1906 and 1921. Gresley improved upon the GER class with various versions of his London and North Eastern Railway N7 class, built between 1925 and 1928. In the United States, 0-6-2 locomotives were 2-6-0 type locomotives, rebuilt with a larger firebox and therefore required greater weight distribution near their backs; the leading wheels were therefore relocated to the rear as trailing wheels. Nearly all of these locomotives were used on branch lines. Many 0-6-2 types were found in the state of Hawaii on sugar cane railroads across the state. Most notable were the 0-6-2T’s of the Mcbryde Sugar Company of Kauai, 3 of which survive and are the only original steam engines operating in Hawaii
Denver and Rio Grande Western Railroad
The Denver & Rio Grande Western Railroad shortened to Rio Grande, D&RG or D&RGW the Denver & Rio Grande Railroad, was an American Class I railroad company. The railroad started as a 3 ft narrow-gauge line running south from Denver, Colorado in 1870, it served as a transcontinental bridge line between Denver, Salt Lake City, Utah. The Rio Grande was a major origin of coal and mineral traffic; the Rio Grande was the epitome of mountain railroading, with a motto of Through the Rockies, not around them and Main line through the Rockies, both referring to the Rocky Mountains. The D&RGW operated the highest mainline rail line in the United States, over the 10,240 feet Tennessee Pass in Colorado, the famed routes through the Moffat Tunnel and the Royal Gorge. At its height in the mid-1880s, the D&RG had the largest narrow-gauge railroad network in North America with 2,783 miles of track interconnecting the states of Colorado, New Mexico, Utah. Known for its independence, the D&RGW operated the Rio Grande Zephyr until its discontinuation in 1983.
This was the last private intercity passenger train in the United States until Brightline began service in Florida in 2018. In 1988, the Rio Grande's parent corporation, Rio Grande Industries, purchased Southern Pacific Transportation Company, as the result of a merger, the larger Southern Pacific Railroad name was chosen for identity; the Rio Grande operated as a separate division of the Southern Pacific, until that company was acquired by the Union Pacific Railroad. Today, most former D&RGW main lines are owned and operated by the Union Pacific while several branch lines are now operated as heritage railways by various companies; the Denver & Rio Grande Railway was incorporated on October 27, 1870 by General William Jackson Palmer, a board of four directors. It was announced that the new 3 ft railroad would proceed south from Denver and travel an estimated 875 miles south to El Paso via Pueblo, westward along the Arkansas River, continue southward through the San Luis Valley of Colorado toward the Rio Grande.
Assisted by his friend and new business partner Dr. William Bell, Palmer's new "Baby Road" laid the first rails out of Denver on July 28, 1871 and reached the location of the new town of Colorado Springs by October 21. Narrow gauge was chosen in part because construction and equipment costs would be more affordable when weighed against that of the prevailing standard gauge. Palmer's first hand impressions of the Ffestiniog Railway in Wales buoyed his interest in the narrow-gauge concept which would prove to be advantageous while conquering the mountainous regions of the Southwest; the route of the D&RG would be amended and added to as new opportunities and competition challenged the railroad's expanding goals. Feverish, competitive construction plans provoked the 1877–1880 war over right of way with the Atchison and Santa Fe Railway. Both rivals hired gunslingers and bought politicians while courts intervened to bring settlement to the disagreements. One anecdote of the conflict recounts June 1879 when the Santa Fe defended its roundhouse in Pueblo with Dodge City toughs led by Bat Masterson.
In March 1880, a Boston Court granted the AT&SF the rights to Raton Pass, while the D&RG paid an exorbitant $1.4 million for the trackage extending through the Arkansas River's Royal Gorge. The D&RG's possession of this route allowed quick access to the booming mining district of Leadville, Colorado. While this "Treaty of Boston" did not favor the purist of original D&RG intentions, the conquering of new mining settlements to the west and the future opportunity to expand into Utah was realized from this settlement. By late 1880 William Bell had begun to organize railway construction in Utah that would become the Palmer controlled Denver & Rio Grande Western Railway in mid-1881; the intention of the D&RGW was to work eastward from Provo to an eventual link with westward bound D&RG in Colorado. This physical connection was realized near Green River, Utah on March 30, 1883, by May of that year the D&RG formally leased its Utah subsidiary as planned. By mid-1883, financial difficulties due to aggressive growth and expenditures led to a shake up among the D&RG board of directors, General Palmer resigned as president of the D&RG in August 1883, while retaining that position with the Western.
Frederick Lovejoy would soon fill Palmer's vacated seat on the D&RG, the first in a succession of post Palmer presidents that would attempt to direct the railroad through future struggles and successes. Following bitter conflict with the Rio Grande Western during lease disagreements and continued financial struggles, the D&RG went into receivership in July 1884 with court appointed receiver William S. Jackson in control. Eventual foreclosure and sale of the original Denver & Rio Grande Railway resulted within two years and the new Denver & Rio Grande Railroad took formal control of the property and holdings on July 14, 1886 with Jackson appointed as president. General Palmer would continue as president of the Utah line until retirement in 1901; the D&RG built west from Pueblo reaching Cañon City in 1874. The line through the Royal Gorge reached Salida on May 20, 1880 and was pushed to Leadville that same year. From Salida, the D&RG pushed west over the Continental Divide at the 10,845 feet Marshall Pass and reached Gunnison on August 6, 1881.
From Gunnison the line entered the Black Canyon of the
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen from which liquid hydrocarbons can be produced, called shale oil. Shale oil is a substitute for conventional crude oil. Deposits of oil shale occur around the world, including major deposits in the United States. A 2016 estimate of global deposits set the total world resources of oil shale equivalent of 6.05 trillion barrels of oil in place. Heating oil shale to a sufficiently high temperature causes the chemical process of pyrolysis to yield a vapor. Upon cooling the vapor, the liquid shale oil—an unconventional oil—is separated from combustible oil-shale gas. Oil shale can be burned directly in furnaces as a low-grade fuel for power generation and district heating or used as a raw material in chemical and construction-materials processing. Oil shale gains attention as a potential abundant source of oil whenever the price of crude oil rises. At the same time, oil-shale mining and processing raise a number of environmental concerns, such as land use, waste disposal, water use, waste-water management, greenhouse-gas emissions and air pollution.
Estonia and China have well-established oil shale industries, Brazil and Russia utilize oil shale. General composition of oil shales constitutes inorganic matrix and kerogen. Oil shales differ from oil-bearing shales, shale deposits that contain petroleum, sometimes produced from drilled wells. Examples of oil-bearing shales are the Bakken Formation, Pierre Shale, Niobrara Formation, Eagle Ford Formation. Oil shale, an organic-rich sedimentary rock, belongs to the group of sapropel fuels, it does not have a definite geological definition nor a specific chemical formula, its seams do not always have discrete boundaries. Oil shales vary in their mineral content, chemical composition, type of kerogen, depositional history and not all oil shales would be classified as shales in the strict sense. According to the petrologist Adrian C. Hutton of the University of Wollongong, oil shales are not "geological nor geochemically distinctive rock but rather'economic' term." Their common defining feature is low solubility in low-boiling organic solvents and generation of liquid organic products on thermal decomposition.
Oil shale differs from bitumen-impregnated rocks, humic coals and carbonaceous shale. While oil sands do originate from the biodegradation of oil and pressure have not transformed the kerogen in oil shale into petroleum, that means that its maturation does not exceed early mesocatagenetic. General composition of oil shales constitutes inorganic matrix and kerogen. While the bitumen portion of oil shales is soluble in carbon disulfide, kerogen portion is insoluble in carbon disulfide and may contain iron, nickel and uranium. Oil shale contains a lower percentage of organic matter than coal. In commercial grades of oil shale the ratio of organic matter to mineral matter lies between 0.75:5 and 1.5:5. At the same time, the organic matter in oil shale has an atomic ratio of hydrogen to carbon 1.2 to 1.8 times lower than for crude oil and about 1.5 to 3 times higher than for coals. The organic components of oil shale derive from a variety of organisms, such as the remains of algae, pollen, plant cuticles and corky fragments of herbaceous and woody plants, cellular debris from other aquatic and land plants.
Some deposits contain significant fossils. The mineral matter in oil shale carbonates. Inorganic matrix can contain quartz, clays, carbonates and some other minerals. Geologists can classify oil shales on the basis of their composition as carbonate-rich shales, siliceous shales, or cannel shales. Another classification, known as the van Krevelen diagram, assigns kerogen types, depending on the hydrogen and oxygen content of oil shales' original organic matter; the most used classification of oil shales, developed between 1987 and 1991 by Adrian C. Hutton, adapts petrographic terms from coal terminology; this classification designates oil shales as terrestrial, lacustrine, or marine, based on the environment of the initial biomass deposit. Known oil shales are predominantly aquatic origin. Hutton's classification scheme has proven useful in estimating the yield and composition of the extracted oil; as source rocks for most conventional oil reservoirs, oil shale deposits are found in all world oil provinces, although most of them are too deep to be exploited economically.
As with all oil and gas resources, analysts distinguish between oil shale resources and oil shale reserves. "Resources" refers to all oil shale deposits, while "reserves", represents those deposits from which producers can extract oil shale economically using existing technology. Since extraction technologies develop continuously, planners can only estimate the amount of recoverable kerogen. Although resources of oil shale occur in many countries, only 33 countries possess known deposits of possible economic value. Well-explored deposits classifiable as reserves, include the Green River deposits in the wester