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126-639: The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado , United States, near the town of Delta . Its geology forms a part of the Morrison Formation and has famously yielded a great diversity of animal remains from the Jurassic Period , among them Ceratosaurus , Supersaurus , and Torvosaurus . The quarry is found within the Uncompahgre National Forest . In 1971, a large theropod phalanx ( Torvosaurus tanneri )

252-535: A characteristic fabric . All three types may melt again, and when this happens, new magma is formed, from which an igneous rock may once again solidify. Organic matter, such as coal, bitumen, oil, and natural gas, is linked mainly to organic-rich sedimentary rocks. To study all three types of rock, geologists evaluate the minerals of which they are composed and their other physical properties, such as texture and fabric . Geologists also study unlithified materials (referred to as superficial deposits ) that lie above

378-689: A gunman killed 10 people , including a police officer, in a King Soopers supermarket in Boulder . In an instance of anti-LGBT violence , a gunman killed 5 people at a nightclub in Colorado Springs during the night of November 19–20, 2022. Four warships of the U.S. Navy have been named the USS Colorado . The first USS Colorado was named for the Colorado River and served in the Civil War and later

504-485: A petrographic microscope , where the minerals can be identified through their different properties in plane-polarized and cross-polarized light, including their birefringence , pleochroism , twinning , and interference properties with a conoscopic lens . In the electron microprobe, individual locations are analyzed for their exact chemical compositions and variation in composition within individual crystals. Stable and radioactive isotope studies provide insight into

630-434: A definite homogeneous chemical composition and an ordered atomic arrangement. Each mineral has distinct physical properties, and there are many tests to determine each of them. Minerals are often identified through these tests. The specimens can be tested for: A rock is any naturally occurring solid mass or aggregate of minerals or mineraloids . Most research in geology is associated with the study of rocks, as they provide

756-623: A length of less than a meter. Rocks at the depth to be ductilely stretched are often also metamorphosed. These stretched rocks can also pinch into lenses, known as boudins , after the French word for "sausage" because of their visual similarity. Where rock units slide past one another, strike-slip faults develop in shallow regions, and become shear zones at deeper depths where the rocks deform ductilely. The addition of new rock units, both depositionally and intrusively, often occurs during deformation. Faulting and other deformational processes result in

882-648: A major industry in Colorado. This period became known locally as the Carnation Gold Rush . Poor labor conditions and discontent among miners resulted in several major clashes between strikers and the Colorado National Guard , including the 1903–1904 Western Federation of Miners Strike and Colorado Coalfield War , the latter of which included the Ludlow massacre that killed a dozen women and children. Both

1008-448: A means to provide information about geological history and the timing of geological events. The principle of uniformitarianism states that the geological processes observed in operation that modify the Earth's crust at present have worked in much the same way over geological time. A fundamental principle of geology advanced by the 18th-century Scottish physician and geologist James Hutton

1134-608: A number of fields, laboratory, and numerical modeling methods to decipher Earth history and to understand the processes that occur on and inside the Earth. In typical geological investigations, geologists use primary information related to petrology (the study of rocks), stratigraphy (the study of sedimentary layers), and structural geology (the study of positions of rock units and their deformation). In many cases, geologists also study modern soils, rivers , landscapes , and glaciers ; investigate past and current life and biogeochemical pathways, and use geophysical methods to investigate

1260-628: A rapid decline in the organization's power, with membership waning significantly by the end of the 1920s. Colorado became the first western state to host a major political convention when the Democratic Party met in Denver in 1908. By the U.S. census in 1930 , the population of Colorado first exceeded one million residents. Colorado suffered greatly through the Great Depression and the Dust Bowl of

1386-451: A sedimentary rock. Sedimentary rocks are mainly divided into four categories: sandstone, shale, carbonate, and evaporite. This group of classifications focuses partly on the size of sedimentary particles (sandstone and shale), and partly on mineralogy and formation processes (carbonation and evaporation). Igneous and sedimentary rocks can then be turned into metamorphic rocks by heat and pressure that change its mineral content, resulting in

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1512-636: A significant portion of the extreme weather occurs in the least populated areas of the state. Thunderstorms are common east of the Continental Divide in the spring and summer, yet are usually brief. Hail is a common sight in the mountains east of the Divide and across the eastern Plains, especially the northeast part of the state. Hail is the most commonly reported warm-season severe weather hazard, and occasionally causes human injuries, as well as significant property damage. The eastern Plains are subject to some of

1638-493: A single environment and do not necessarily occur in a single order. The Hawaiian Islands , for example, consist almost entirely of layered basaltic lava flows. The sedimentary sequences of the mid-continental United States and the Grand Canyon in the southwestern United States contain almost-undeformed stacks of sedimentary rocks that have remained in place since Cambrian time. Other areas are much more geologically complex. In

1764-555: A specific building was constructed in 1976 for the BYU Earth Science Museum, known in the present day as the BYU Museum of Paleontology . Under the direction of the BYU Earth Science Museum, the quarry has been excavated for 13 field seasons. Approximately 4000 bones have been collected, making it one of the most prolific dinosaur producing accumulations in the Morrison Formation . Thirty vertebrate genera are represented in

1890-400: A variety of applications. Dating of lava and volcanic ash layers found within a stratigraphic sequence can provide absolute age data for sedimentary rock units that do not contain radioactive isotopes and calibrate relative dating techniques. These methods can also be used to determine ages of pluton emplacement. Thermochemical techniques can be used to determine temperature profiles within

2016-558: Is a 2 meter thick, 121 meter wide, very poorly sorted pebble-rich sublith arenite . The channel sandstone shows abundant trough cross-stratification and a possible antidune bedform composed of gravel and sand which indicates flow velocities as high as 200 cm/s (5 miles/hour). Measured bone volumes can be equated to flow velocities . These calculated bone volume velocities are in agreement with flow velocities determined from grain size and bedforms. The river flow direction, based upon bedform orientations and bone elongation statistics,

2142-512: Is a mix of high plains, foothills, and mountains. Northwest and west Colorado are predominantly mountainous, with some desert lands mixed in. Southwest and southern Colorado are a complex mixture of desert and mountain areas. The climate of the Eastern Plains is semi-arid ( Köppen climate classification : BSk ) with low humidity and moderate precipitation, usually from 15 to 25 inches (380 to 640 millimeters) annually, although many areas near

2268-422: Is accomplished in two primary ways: through faulting and folding . In the shallow crust, where brittle deformation can occur, thrust faults form, which causes the deeper rock to move on top of the shallower rock. Because deeper rock is often older, as noted by the principle of superposition , this can result in older rocks moving on top of younger ones. Movement along faults can result in folding, either because

2394-460: Is an intimate coupling between the movement of the plates on the surface and the convection of the mantle (that is, the heat transfer caused by the slow movement of ductile mantle rock). Thus, oceanic parts of plates and the adjoining mantle convection currents always move in the same direction – because the oceanic lithosphere is actually the rigid upper thermal boundary layer of the convecting mantle. This coupling between rigid plates moving on

2520-806: Is drained by the Colorado River. The South Park of Colorado is the region of the headwaters of the South Platte River. In south-central Colorado is the large San Luis Valley , where the headwaters of the Rio Grande are located. The northern part of the valley is the San Luis Closed Basin , an endorheic basin that helped created the Great Sand Dunes . The valley sits between the Sangre de Cristo Mountains and San Juan Mountains . The Rio Grande drains due south into New Mexico, Texas, and Mexico. Across

2646-659: Is flat and rolling land. East of the Rocky Mountains is the Colorado Eastern Plains of the High Plains , the section of the Great Plains within Colorado at elevations ranging from roughly 3,350 to 7,500 feet (1,020 to 2,290 m). The Colorado plains are mostly prairies but also include deciduous forests , buttes , and canyons. Precipitation averages 15 to 25 inches (380 to 640 mm) annually. Eastern Colorado

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2772-533: Is generally accessed through artesian wells . Heavy usage of these wells for irrigation purposes caused underground water reserves to decline in the region. Eastern Colorado also hosts a considerable amount and range of livestock, such as cattle ranches and hog farms. Roughly 70% of Colorado's population resides along the eastern edge of the Rocky Mountains in the Front Range Urban Corridor between Cheyenne, Wyoming , and Pueblo, Colorado . This region

2898-739: Is higher than the high elevation points of 18 states and the District of Columbia. 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 towards the Gulf of California . Within

3024-433: Is horizontal). The principle of superposition states that a sedimentary rock layer in a tectonically undisturbed sequence is younger than the one beneath it and older than the one above it. Logically a younger layer cannot slip beneath a layer previously deposited. This principle allows sedimentary layers to be viewed as a form of the vertical timeline, a partial or complete record of the time elapsed from deposition of

3150-616: Is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources , understanding natural hazards , remediating environmental problems, and providing insights into past climate change . Geology is a major academic discipline , and it is central to geological engineering and plays an important role in geotechnical engineering . The majority of geological data comes from research on solid Earth materials. Meteorites and other extraterrestrial natural materials are also studied by geological methods. Minerals are naturally occurring elements and compounds with

3276-521: Is known as "The Western Slope") are the cities of Grand Junction , Durango , and Montrose . Download coordinates as: To the west of the Great Plains of Colorado rises the eastern slope of the Rocky Mountains . Notable peaks of the Rocky Mountains include Longs Peak , Mount Blue Sky , Pikes Peak , and the Spanish Peaks near Walsenburg , in southern Colorado. This area drains to the east and

3402-459: Is more complex than states outside of the Mountain States region. Unlike most other states, southern Colorado is not always warmer than northern Colorado. Most of Colorado is made up of mountains, foothills, high plains, and desert lands. Mountains and surrounding valleys greatly affect the local climate. Northeast, east, and southeast Colorado are mostly the high plains, while Northern Colorado

3528-510: Is partially 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, Boulder , Fort Collins , Loveland, Castle Rock , Colorado Springs, Pueblo, Greeley, and other townships and municipalities in between. On the other side of the Rockies, the significant population centers in western Colorado (which

3654-546: Is presently mainly farmland and rangeland, along with small farming villages and towns. Corn , wheat , hay , soybeans , and oats are all typical crops. Most villages and towns in this region boast both a water tower and a grain elevator . Irrigation water is available from both surface and subterranean sources. Surface water sources include the South Platte , the Arkansas River , and a few other streams. Subterranean water

3780-478: Is primarily accomplished through normal faulting and through the ductile stretching and thinning. Normal faults drop rock units that are higher below those that are lower. This typically results in younger units ending up below older units. Stretching of units can result in their thinning. In fact, at one location within the Maria Fold and Thrust Belt , the entire sedimentary sequence of the Grand Canyon appears over

3906-568: Is that "the present is the key to the past." In Hutton's words: "the past history of our globe must be explained by what can be seen to be happening now." The principle of intrusive relationships concerns crosscutting intrusions. In geology, when an igneous intrusion cuts across a formation of sedimentary rock , it can be determined that the igneous intrusion is younger than the sedimentary rock. Different types of intrusions include stocks, laccoliths , batholiths , sills and dikes . The principle of cross-cutting relationships pertains to

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4032-457: Is the highest point in Colorado and the Rocky Mountains of North America. Colorado is the only U.S. state that lies entirely above 1,000 meters elevation. The point where the Arikaree River flows out of Yuma County, Colorado , and into Cheyenne County, Kansas , is the lowest in Colorado at 3,317 feet (1,011 m) elevation. This point, which is the highest low elevation point of any state,

4158-518: Is to demonstrate the age of the Earth . Geology provides evidence for plate tectonics , the evolutionary history of life , and the Earth's past climates . Geologists broadly study the properties and processes of Earth and other terrestrial planets. Geologists use a wide variety of methods to understand the Earth's structure and evolution, including fieldwork , rock description , geophysical techniques , chemical analysis , physical experiments , and numerical modelling . In practical terms, geology

4284-557: Is today the State of Colorado has been inhabited by Native Americans and their Paleoamerican ancestors for at least 13,500 years and possibly more than 37,000 years. The eastern edge of the Rocky Mountains was a major migration route that was important to the spread of early peoples throughout the Americas. The Lindenmeier site in Larimer County contains artifacts dating from approximately 8720 BCE. The Ancient Pueblo peoples lived in

4410-523: Is used for geologically young materials containing organic carbon . The geology of an area changes through time as rock units are deposited and inserted, and deformational processes alter their shapes and locations. Rock units are first emplaced either by deposition onto the surface or intrusion into the overlying rock . Deposition can occur when sediments settle onto the surface of the Earth and later lithify into sedimentary rock, or when as volcanic material such as volcanic ash or lava flows blanket

4536-432: Is very prone to droughts. Most of the precipitation comes from thunderstorms, which can be severe, and from major snowstorms that occur in the winter and early spring. Otherwise, winters tend to be mostly dry and cold. In much of the region, March is the snowiest month. April and May are normally the rainiest months, while April is the wettest month overall. The Front Range cities closer to the mountains tend to be warmer in

4662-561: The Adams-Onís Treaty of 1819. The treaty took effect on February 22, 1821. Having settled its border with Spain, the U.S. admitted the southeastern portion of the Territory of Missouri to the Union as the state of Missouri on August 10, 1821. The remainder of Missouri Territory, including what would become northeastern Colorado, became an unorganized territory and remained so for 33 years over

4788-574: The Asiatic Squadron , where it was attacked during the 1871 Korean Expedition . The later three ships were named in honor of the state, including an armored cruiser and the battleship USS Colorado , the latter of which was the lead ship of her class and served in World War II in the Pacific beginning in 1941. At the time of the attack on Pearl Harbor , the battleship USS Colorado was located at

4914-547: The Great Lakes region to hunt across the High Plains of Colorado and Wyoming . The Spanish Empire claimed Colorado as part of Nuevo México . The U.S. acquired the territorial claim to the eastern Rocky Mountains with the Louisiana Purchase from France in 1803. This U.S. claim conflicted with the claim by Spain to the upper Arkansas River Basin . In 1806, Zebulon Pike led a U.S. Army reconnaissance expedition into

5040-696: The Provisional Government of the Territory of Jefferson on August 24, 1859, but this new territory failed to secure approval from the Congress of the United States embroiled in the debate over slavery. The election of Abraham Lincoln for the President of the United States on November 6, 1860, led to the secession of nine southern slave states and the threat of civil war among the states . Seeking to augment

5166-632: The Sangre de Cristo Range to the east of the San Luis Valley lies the Wet Mountain Valley . These basins, particularly the San Luis Valley, lie along the Rio Grande rift , a major geological formation of the Rocky Mountains, and its branches. The Western Slope of Colorado includes the western face of the Rocky Mountains and all of the area to the western border. This area includes several terrains and climates from alpine mountains to arid deserts. The Western Slope includes many ski resort towns in

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5292-545: The Territory of New Mexico , and the Territory of Utah . On April 9, 1851, Hispano settlers from the area of Taos settled the village of San Luis , then in the New Mexico Territory , as Colorado's first permanent Euro-American settlement , further cementing the traditions of New Mexican cuisine and New Mexico music in the developing Southern Rocky Mountain Front . In 1854, Senator Stephen A. Douglas persuaded

5418-574: The U.S. Congress to divide the unorganized territory east of the Continental Divide into two new organized territories, the Territory of Kansas and the Territory of Nebraska , and an unorganized southern region known as the Indian Territory . Each new territory was to decide the fate of slavery within its boundaries, but this compromise merely served to fuel animosity between free soil and pro-slavery factions. The gold seekers organized

5544-542: The Union as the 38th state. The Spanish adjective "colorado" means "colored red" or "ruddy". Colorado is nicknamed the " Centennial State " because it became a state 100 years (and four weeks) after the signing of the United States Declaration of Independence . Denver is the capital, the most populous city , and the center of the Front Range Urban Corridor . Colorado Springs is the second most populous city of

5670-502: The Union cause. In 1862, a force of Texas cavalry invaded the Territory of New Mexico and captured Santa Fe on March 10. The object of this Western Campaign was to seize or disrupt Colorado and California's gold fields and seize Pacific Ocean ports for the Confederacy. A hastily organized force of Colorado volunteers force-marched from Denver City, Colorado Territory , to Glorieta Pass , New Mexico Territory, in an attempt to block

5796-597: The Ute Indian reservation in southwestern Colorado. The Ute people were removed from the San Juan Mountains the following year. The United States Congress passed an enabling act on March 3, 1875, specifying the requirements for the Territory of Colorado to become a state. On August 1, 1876 (four weeks after the Centennial of the United States ), U.S. President Ulysses S. Grant signed a proclamation admitting Colorado to

5922-500: The bedrock . This study is often known as Quaternary geology , after the Quaternary period of geologic history, which is the most recent period of geologic time. Magma is the original unlithified source of all igneous rocks . The active flow of molten rock is closely studied in volcanology , and igneous petrology aims to determine the history of igneous rocks from their original molten source to their final crystallization. In

6048-470: The free Territory of Colorado . The original boundaries of Colorado remain unchanged except for government survey amendments. In 1776, Spanish priest Silvestre Vélez de Escalante recorded that Native Americans in the area knew the river as el Rio Colorado for the red-brown silt that the river carried from the mountains. In 1859, a U.S. Army topographic expedition led by Captain John Macomb located

6174-512: The geochemical evolution of rock units. Petrologists can also use fluid inclusion data and perform high temperature and pressure physical experiments to understand the temperatures and pressures at which different mineral phases appear, and how they change through igneous and metamorphic processes. This research can be extrapolated to the field to understand metamorphic processes and the conditions of crystallization of igneous rocks. This work can also help to explain processes that occur within

6300-402: The mantle below (separated within itself by seismic discontinuities at 410 and 660 kilometers), and the outer core and inner core below that. More recently, seismologists have been able to create detailed images of wave speeds inside the earth in the same way a doctor images a body in a CT scan . These images have led to a much more detailed view of the interior of the Earth, and have replaced

6426-574: The question of slavery . After 11 years of war, Spain finally recognized the independence of Mexico with the Treaty of Córdoba signed on August 24, 1821. Mexico eventually ratified the Adams–Onís Treaty in 1831. The Texian Revolt of 1835–36 fomented a dispute between the U.S. and Mexico which eventually erupted into the Mexican–American War in 1846. Mexico surrendered its northern territory to

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6552-581: The 1913–1914 Coalfield War and the Denver streetcar strike of 1920 resulted in federal troops intervening to end the violence. In 1927, the 1927-28 Colorado coal strike occurred and was ultimately successful in winning a dollar a day increase in wages. During it however the Columbine Mine massacre resulted in six dead strikers following a confrontation with Colorado Rangers . In a separate incident in Trinidad

6678-463: The 1930s, but a major wave of immigration following World War II boosted Colorado's fortune. Tourism became a mainstay of the state economy, and high technology became an important economic engine. The United States Census Bureau estimated that the population of Colorado exceeded five million in 2009. On September 11, 1957, a plutonium fire occurred at the Rocky Flats Plant , which resulted in

6804-440: The 1960s, it was discovered that the Earth's lithosphere , which includes the crust and rigid uppermost portion of the upper mantle , is separated into tectonic plates that move across the plastically deforming, solid, upper mantle, which is called the asthenosphere . This theory is supported by several types of observations, including seafloor spreading and the global distribution of mountain terrain and seismicity. There

6930-467: The Americas. In 1848, much of the Nuevo México region was annexed to the United States with the Treaty of Guadalupe Hidalgo . The Pike's Peak Gold Rush of 1858–1862 created an influx of settlers. On February 28, 1861, U.S. President James Buchanan signed an act creating the Territory of Colorado , and on August 1, 1876, President Ulysses S. Grant signed Proclamation 230 , admitting Colorado to

7056-484: The Dry Mesa area, a severe drought resulted in the mass mortality of dinosaurs and other vertebrates . These animals were attracted to a remnant water hole of the dry Lake T'oo'dichi' lake bed where they died of starvation and dehydration. This mass mortality produced a considerable accumulation of disarticulated vertebrate remains. Subsequently, a short-lived flash flood traversed the dry lake beds. The quarry sandstone bed

7182-437: The Earth and other astronomical objects , the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences , including hydrology . It is integrated with Earth system science and planetary science . Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study

7308-424: The Earth, such as subduction and magma chamber evolution. Structural geologists use microscopic analysis of oriented thin sections of geological samples to observe the fabric within the rocks, which gives information about strain within the crystalline structure of the rocks. They also plot and combine measurements of geological structures to better understand the orientations of faults and folds to reconstruct

7434-478: The Grand Canyon in the southwestern United States being a very visible example, the lower rock units were metamorphosed and deformed, and then deformation ended and the upper, undeformed units were deposited. Although any amount of rock emplacement and rock deformation can occur, and they can occur any number of times, these concepts provide a guide to understanding the geological history of an area. Geologists use

7560-565: The Green River briefly crosses over into Colorado. The Western Slope of Colorado is drained by the Colorado River and its tributaries (primarily the Gunnison River , Green River , and the San Juan River ). The Colorado River flows through Glenwood Canyon , and then through an arid valley made up of desert from Rifle to Parachute , through the desert canyon of De Beque Canyon , and into

7686-463: The Rocky Mountains and towns west to Utah. It is less populous than the Front Range but includes a large number of national parks and monuments. The northwestern corner of Colorado is a sparsely populated region, and it contains part of the noted Dinosaur National Monument , which not only is a paleontological area, but is also a scenic area of rocky hills, canyons, arid desert, and streambeds. Here,

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7812-725: The Southwestern United States. In 1864, Territorial Governor John Evans appointed the Reverend John Chivington as Colonel of the Colorado Volunteers with orders to protect white settlers from Cheyenne and Arapaho warriors who were accused of stealing cattle. Colonel Chivington ordered his troops to attack a band of Cheyenne and Arapaho encamped along Sand Creek. Chivington reported that his troops killed more than 500 warriors. The militia returned to Denver City in triumph, but several officers reported that

7938-697: The Territory. The Union Pacific linked up with the Central Pacific Railroad at Promontory Summit, Utah , on May 10, 1869, to form the First transcontinental railroad . The Denver Pacific Railway reached Denver in June of the following year, and the Kansas Pacific arrived two months later to forge the second line across the continent. In 1872, rich veins of silver were discovered in the San Juan Mountains on

8064-466: The Texans. On March 28, the Coloradans and local New Mexico volunteers stopped the Texans at the Battle of Glorieta Pass , destroyed their cannon and supply wagons, and dispersed 500 of their horses and mules. The Texans were forced to retreat to Santa Fe. Having lost the supplies for their campaign and finding little support in New Mexico, the Texans abandoned Santa Fe and returned to San Antonio in defeat. The Confederacy made no further attempts to seize

8190-408: The U.S. with the Treaty of Guadalupe Hidalgo after the war in 1848; this included much of the western and southern areas of Colorado. Most American settlers first traveled to Colorado through the Santa Fe Trail , which connected the U.S. to Santa Fe and the Camino Real de Tierra Adentro southward. Others were traveling overland west to the Oregon Country , the new goldfields of California , or

8316-399: The Union as the 38th state and earning it the moniker "Centennial State". The discovery of a major silver lode near Leadville in 1878 triggered the Colorado Silver Boom . The Sherman Silver Purchase Act of 1890 invigorated silver mining, and Colorado's last, but greatest, gold strike at Cripple Creek a few months later lured a new generation of gold seekers. Colorado women were granted

8442-442: The Western Slope can be found at Colorado Mesa University in Grand Junction, Western Colorado University in Gunnison, Fort Lewis College in Durango, and Colorado Mountain College in Glenwood Springs and Steamboat Springs. The Four Corners Monument in the southwest corner of Colorado marks the common boundary of Colorado, New Mexico , Arizona , and Utah ; the only such place in the United States. The climate of Colorado

8568-447: The Western Slope. Grand Junction and Durango are the only major centers of television broadcasting west of the Continental Divide in Colorado, though most mountain resort communities publish daily newspapers. Grand Junction is located at the juncture of Interstate 70 and US 50, the only major highways in western Colorado. Grand Junction is also along the major railroad of the Western Slope, the Union Pacific . This railroad also provides

8694-499: The alpine snow melts by mid-August except for a few snow-capped peaks and a few small glaciers. The Colorado Mineral Belt , stretching from the San Juan Mountains in the southwest to Boulder and Central City on the front range, contains most of the historic gold- and silver-mining districts of Colorado. The 30 highest major summits of the Rocky Mountains of North America are all within the state. The summit of Mount Elbert at 14,437.6 feet (4,400.58 m) elevation in Lake County

8820-403: The arid desert of Grand Valley , where the city of Grand Junction is located. Also prominent is the Grand Mesa , which lies to the southeast of Grand Junction; the high San Juan Mountains, a rugged mountain range; and to the north and west of the San Juan Mountains, the Colorado Plateau . Grand Junction, Colorado , at the confluence of the Colorado and Gunnison Rivers, is the largest city on

8946-537: The beginning of the 20th century, advancement in geological science was facilitated by the ability to obtain accurate absolute dates to geological events using radioactive isotopes and other methods. This changed the understanding of geological time. Previously, geologists could only use fossils and stratigraphic correlation to date sections of rock relative to one another. With isotopic dates, it became possible to assign absolute ages to rock units, and these absolute dates could be applied to fossil sequences in which there

9072-458: The biggest hail storms in North America. Notable examples are the severe hailstorms that hit Denver on July 11, 1990, and May 8, 2017, the latter being the costliest ever in the state. Geologic Geology (from Ancient Greek γῆ ( gê )  'earth' and λoγία ( -logía )  'study of, discourse') is a branch of natural science concerned with

9198-493: The boundaries of the new Territory of Colorado exclusively by lines of latitude and longitude , stretching from 37°N to 41°N latitude, and from 102°02′48″W to 109°02′48″W longitude ( 25°W to 32°W from the Washington Meridian ). After 163 years of government surveys, the borders of Colorado were officially defined by 697 boundary markers and 697 straight boundary lines . Colorado, Wyoming , and Utah are

9324-625: The confluence of the Green River with the Grand River in what is now Canyonlands National Park in Utah . The Macomb party designated the confluence as the source of the Colorado River. On April 12, 1861, South Carolina artillery opened fire on Fort Sumter to start the American Civil War . While many gold seekers held sympathies for the Confederacy , the vast majority remained fiercely loyal to

9450-515: The creation of topographic gradients, causing material on the rock unit that is increasing in elevation to be eroded by hillslopes and channels. These sediments are deposited on the rock unit that is going down. Continual motion along the fault maintains the topographic gradient in spite of the movement of sediment and continues to create accommodation space for the material to deposit. Deformational events are often also associated with volcanism and igneous activity. Volcanic ashes and lavas accumulate on

9576-437: The crust, the uplift of mountain ranges, and paleo-topography. Fractionation of the lanthanide series elements is used to compute ages since rocks were removed from the mantle. Other methods are used for more recent events. Optically stimulated luminescence and cosmogenic radionuclide dating are used to date surfaces and/or erosion rates. Dendrochronology can also be used for the dating of landscapes. Radiocarbon dating

9702-466: The disputed region. Colonel Pike and his troops were arrested by Spanish cavalrymen in the San Luis Valley the following February, taken to Chihuahua , and expelled from Mexico the following July. The U.S. relinquished its claim to all land south and west of the Arkansas River and south of 42nd parallel north and west of the 100th meridian west as part of its purchase of Florida from Spain with

9828-526: The entire Great Basin and all lands drained by the rivers Green , Grand , and Colorado . The federal government of the U.S. flatly refused to recognize the new Mormon government because it was theocratic and sanctioned plural marriage . Instead, the Compromise of 1850 divided the Mexican Cession and the northwestern claims of Texas into a new state and two new territories, the state of California ,

9954-570: The fault is a normal fault or a thrust fault . The principle of inclusions and components states that, with sedimentary rocks, if inclusions (or clasts ) are found in a formation, then the inclusions must be older than the formation that contains them. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. A similar situation with igneous rocks occurs when xenoliths are found. These foreign bodies are picked up as magma or lava flows, and are incorporated, later to cool in

10080-403: The faults are not planar or because rock layers are dragged along, forming drag folds as slip occurs along the fault. Deeper in the Earth, rocks behave plastically and fold instead of faulting. These folds can either be those where the material in the center of the fold buckles upwards, creating " antiforms ", or where it buckles downwards, creating " synforms ". If the tops of the rock units within

10206-483: The folds remain pointing upwards, they are called anticlines and synclines , respectively. If some of the units in the fold are facing downward, the structure is called an overturned anticline or syncline, and if all of the rock units are overturned or the correct up-direction is unknown, they are simply called by the most general terms, antiforms, and synforms. Even higher pressures and temperatures during horizontal shortening can cause both folding and metamorphism of

10332-404: The formation of faults and the age of the sequences through which they cut. Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault. Finding the key bed in these situations may help determine whether

10458-479: The infamous Columbine High School massacre in 1999 which made international news, where two gunmen killed 12 students and one teacher, before committing suicide. The incident has spawned many copycat incidents . On July 20, 2012, a gunman killed 12 people in a movie theater in Aurora . The state responded with tighter restrictions on firearms, including introducing a limit on magazine capacity. On March 22, 2021,

10584-567: 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 Wyoming and Nebraska. Just to the south of North Park, but on the western side of the Continental Divide, is the Middle Park of Colorado , which

10710-423: The internal composition and structure of the Earth. Seismologists can use the arrival times of seismic waves to image the interior of the Earth. Early advances in this field showed the existence of a liquid outer core (where shear waves were not able to propagate) and a dense solid inner core . These advances led to the development of a layered model of the Earth, with a lithosphere (including crust) on top,

10836-459: The later end of the scale, it is marked by the present day (in the Holocene epoch ). The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in

10962-617: The local and state Democrat and Republican parties , particularly in the governor's office and city governments of Denver, Cañon City , and Durango . A particularly strong element of the Klan controlled the Denver Police . Cross burnings became semi-regular occurrences in cities such as Florence and Pueblo. The Klan targeted African-Americans, Catholics , Eastern European immigrants, and other non-White Protestant groups. Efforts by non-Klan lawmen and lawyers including Philip Van Cise led to

11088-454: The lowest layer to deposition of the highest bed. The principle of faunal succession is based on the appearance of fossils in sedimentary rocks. As organisms exist during the same period throughout the world, their presence or (sometimes) absence provides a relative age of the formations where they appear. Based on principles that William Smith laid out almost a hundred years before the publication of Charles Darwin 's theory of evolution ,

11214-493: The mantle and show the crystallographic structures expected in the inner core of the Earth. The geological time scale encompasses the history of the Earth. It is bracketed at the earliest by the dates of the first Solar System material at 4.567 Ga (or 4.567 billion years ago) and the formation of the Earth at 4.54 Ga (4.54 billion years), which is the beginning of the Hadean eon  – a division of geological time. At

11340-405: The matrix. As a result, xenoliths are older than the rock that contains them. The principle of original horizontality states that the deposition of sediments occurs as essentially horizontal beds. Observation of modern marine and non-marine sediments in a wide variety of environments supports this generalization (although cross-bedding is inclined, the overall orientation of cross-bedded units

11466-673: The mayor was accused of deputizing members of the KKK against the striking workers. More than 5,000 Colorado miners—many immigrants—are estimated to have died in accidents since records were first formally collected following an 1884 accident in Crested Butte that killed 59. In 1924, the Ku Klux Klan Colorado Realm achieved dominance in Colorado politics. With peak membership levels, the Second Klan levied significant control over both

11592-542: The midst and aftermath of the Civil War, many discouraged prospectors returned to their homes, but a few stayed and developed mines, mills, farms, ranches, roads, and towns in Colorado Territory. On September 14, 1864, James Huff discovered silver near Argentine Pass , the first of many silver strikes. In 1867, the Union Pacific Railroad laid its tracks west to Weir, now Julesburg , in the northeast corner of

11718-418: The mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages . By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect

11844-452: The most diverse Upper Jurassic vertebrate assemblages in the world. This fossil assemblage was deposited within a poorly sorted sandstone bed that is stratigraphically situated in the lower portion of the upper Brushy Basin Member of the Morrison Formation . The bone accumulation, consisting of thousands of bones, was the consequence of two cataclysmic events, a drought , and flash flood . In

11970-516: The naval base in San Diego, California, and thus went unscathed. The most recent vessel to bear the name USS Colorado is Virginia-class submarine USS Colorado (SSN-788) , which was commissioned in 2018. Colorado is notable for its diverse geography, which includes alpine mountains, high plains, deserts with huge sand dunes, and deep canyons. In 1861, the United States Congress defined

12096-788: The new Mormon settlements of the State of Deseret in the Salt Lake Valley , avoided the rugged Southern Rocky Mountains , and instead followed the North Platte River and Sweetwater River to South Pass (Wyoming) , the lowest crossing of the Continental Divide between the Southern Rocky Mountains and the Central Rocky Mountains. In 1849, the Mormons of the Salt Lake Valley organized the extralegal State of Deseret , claiming

12222-473: The only states that have their borders defined solely 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 . The Four Corners Monument , located at the place where Colorado, New Mexico , Arizona , and Utah meet, is the only place in the United States where four states meet. Approximately half of Colorado

12348-620: The plains and into the foothills, there is a wide variety of climate types. Locations merely a few miles apart can experience entirely different weather depending on the topography. Most valleys have a semi-arid climate, not unlike the eastern plains, which transitions to an alpine climate at the highest elevations. Microclimates also exist in local areas that run nearly the entire spectrum of climates, including subtropical highland ( Cfb/Cwb ), humid subtropical ( Cfa ), humid continental ( Dfa/Dfb ), Mediterranean ( Csa/Csb ) and subarctic ( Dfc ). Extreme weather changes are common in Colorado, although

12474-561: The political power of the Union states , the Republican Party -dominated Congress quickly admitted the eastern portion of the Territory of Kansas into the Union as the free State of Kansas on January 29, 1861, leaving the western portion of the Kansas Territory, and its gold-mining areas, as unorganized territory. Thirty days later on February 28, 1861, outgoing U.S. President James Buchanan signed an Act of Congress organizing

12600-444: The population of Colorado resides, lies in a pronounced precipitation shadow as a result of being on the lee side of the Rocky Mountains. In summer, this area can have many days above 95 °F (35 °C) and often 100 °F (38 °C). On the plains, the winter lows usually range from 25 to −10 °F (−4 to −23 °C). About 75% of the precipitation falls within the growing season, from April to September, but this area

12726-413: The primary record of the majority of the geological history of the Earth. There are three major types of rock: igneous , sedimentary , and metamorphic . The rock cycle illustrates the relationships among them (see diagram). When a rock solidifies or crystallizes from melt ( magma or lava ), it is an igneous rock . This rock can be weathered and eroded , then redeposited and lithified into

12852-569: The principles of succession developed independently of evolutionary thought. The principle becomes quite complex, however, given the uncertainties of fossilization, localization of fossil types due to lateral changes in habitat ( facies change in sedimentary strata), and that not all fossils formed globally at the same time. Geologists also use methods to determine the absolute age of rock samples and geological events. These dates are useful on their own and may also be used in conjunction with relative dating methods or to calibrate relative methods. At

12978-495: The quarry including dinosaurs , a pterosaur , crocodile, turtle, lungfish , and a prototherian mammal. Twenty-three genera of dinosaurs have been found in the quarry distinguishing it as the most diverse Jurassic dinosaur assemblage. The quarry is especially recognized for its large sauropods, among which Supersaurus vivianae and Ultrasauros macintoshi are the most celebrated finds (Richmond and Morris, 1999). The Dry Mesa Dinosaur Quarry of western Colorado yields one of

13104-483: The right to vote on November 7, 1893, making Colorado the second state to grant universal suffrage and the first one by a popular vote (of Colorado men). The repeal of the Sherman Silver Purchase Act in 1893 led to a staggering collapse of the mining and agricultural economy of Colorado, but the state slowly and steadily recovered. Between the 1880s and 1930s, Denver's floriculture industry developed into

13230-405: The rivers are semi-humid climate. The area is known for its abundant sunshine and cool, clear nights, which give this area a great average diurnal temperature range . The difference between the highs of the days and the lows of the nights can be considerable as warmth dissipates to space during clear nights, the heat radiation not being trapped by clouds. The Front Range urban corridor, where most of

13356-428: The rocks. This metamorphism causes changes in the mineral composition of the rocks; creates a foliation , or planar surface, that is related to mineral growth under stress. This can remove signs of the original textures of the rocks, such as bedding in sedimentary rocks, flow features of lavas , and crystal patterns in crystalline rocks . Extension causes the rock units as a whole to become longer and thinner. This

13482-471: The significant plutonium contamination of surrounding populated areas. From the 1940s and 1970s, many protest movements gained momentum in Colorado, predominantly in Denver. This included the Chicano Movement , a civil rights , and social movement of Mexican Americans emphasizing a Chicano identity that is widely considered to have begun in Denver. The National Chicano Youth Liberation Conference

13608-433: The simplified layered model with a much more dynamic model. Mineralogists have been able to use the pressure and temperature data from the seismic and modeling studies alongside knowledge of the elemental composition of the Earth to reproduce these conditions in experimental settings and measure changes within the crystal structure. These studies explain the chemical changes associated with the major seismic discontinuities in

13734-477: The so-called battle was a blatant massacre of Indians at peace, that most of the dead were women and children, and that the bodies of the dead had been hideously mutilated and desecrated. Three U.S. Army inquiries condemned the action, and incoming President Andrew Johnson asked Governor Evans for his resignation, but none of the perpetrators was ever punished. This event is now known as the Sand Creek massacre . In

13860-643: The southeast, ultimately either via the Mississippi River or the Rio Grande into the Gulf of Mexico . The Rocky Mountains within Colorado contain 53 true peaks and 58 named peaks that are 14,000 feet (4,267 m) or higher in elevation above sea level, known as fourteeners . These mountains are largely covered with trees such as conifers and aspens up to the tree line , at an elevation of about 12,000 feet (3,658 m) in southern Colorado to about 10,500 feet (3,200 m) in northern Colorado. Above this tree line, only alpine vegetation grows. Much of

13986-524: The southwestern United States, sedimentary, volcanic, and intrusive rocks have been metamorphosed, faulted, foliated, and folded. Even older rocks, such as the Acasta gneiss of the Slave craton in northwestern Canada , the oldest known rock in the world have been metamorphosed to the point where their origin is indiscernible without laboratory analysis. In addition, these processes can occur in stages. In many places,

14112-456: The state. Residents of the state are known as Coloradans , although the antiquated "Coloradoan" is occasionally used. Major parts of the economy include government and defense, mining, agriculture , tourism, and increasingly other kinds of manufacturing. With increasing temperatures and decreasing water availability, Colorado's agriculture forestry, and tourism economies are expected to be heavily affected by climate change . The region that

14238-550: The subsurface. Sub-specialities of geology may distinguish endogenous and exogenous geology. Geological field work varies depending on the task at hand. Typical fieldwork could consist of: In addition to identifying rocks in the field ( lithology ), petrologists identify rock samples in the laboratory. Two of the primary methods for identifying rocks in the laboratory are through optical microscopy and by using an electron microprobe . In an optical mineralogy analysis, petrologists analyze thin sections of rock samples using

14364-407: The surface of the Earth and the convecting mantle is called plate tectonics . The development of plate tectonics has provided a physical basis for many observations of the solid Earth . Long linear regions of geological features are explained as plate boundaries: Plate tectonics has provided a mechanism for Alfred Wegener 's theory of continental drift , in which the continents move across

14490-488: The surface of the Earth over geological time. They also provided a driving force for crustal deformation, and a new setting for the observations of structural geology. The power of the theory of plate tectonics lies in its ability to combine all of these observations into a single theory of how the lithosphere moves over the convecting mantle. Advances in seismology , computer modeling , and mineralogy and crystallography at high temperatures and pressures give insights into

14616-474: The surface, and igneous intrusions enter from below. Dikes , long, planar igneous intrusions, enter along cracks, and therefore often form in large numbers in areas that are being actively deformed. This can result in the emplacement of dike swarms , such as those that are observable across the Canadian shield, or rings of dikes around the lava tube of a volcano. All of these processes do not necessarily occur in

14742-742: The surface. Igneous intrusions such as batholiths , laccoliths , dikes , and sills , push upwards into the overlying rock, and crystallize as they intrude. After the initial sequence of rocks has been deposited, the rock units can be deformed and/or metamorphosed . Deformation typically occurs as a result of horizontal shortening, horizontal extension , or side-to-side ( strike-slip ) motion. These structural regimes broadly relate to convergent boundaries , divergent boundaries , and transform boundaries, respectively, between tectonic plates. When rock units are placed under horizontal compression , they shorten and become thicker. Because rock units, other than muds, do not significantly change in volume , this

14868-407: The third timeline, the most recent period is expanded in the fourth timeline, and the most recent epoch is expanded in the fifth timeline. Horizontal scale is Millions of years (above timelines) / Thousands of years (below timeline) Epochs: Methods for relative dating were developed when geology first emerged as a natural science . Geologists still use the following principles today as

14994-495: The tracks for Amtrak 's California Zephyr passenger train, which crosses the Rocky Mountains between Denver and Grand Junction. The Western Slope includes multiple notable destinations in the Colorado Rocky Mountains, including Glenwood Springs , with its resort hot springs, and the ski resorts of Aspen , Breckenridge , Vail , Crested Butte , Steamboat Springs , and Telluride . Higher education in and near

15120-751: The valleys and mesas of the Colorado Plateau in far southwestern Colorado. The Ute Nation inhabited the mountain valleys of the Southern Rocky Mountains and the Western Rocky Mountains , even as far east as the Front Range of the present day. The Apache and the Comanche also inhabited the Eastern and Southeastern parts of the state. In the 17th century, the Arapaho and Cheyenne moved west from

15246-467: The winter due to Chinook winds which warms the area, sometimes bringing temperatures of 70 °F (21 °C) or higher in the winter. The average July temperature is 55 °F (13 °C) in the morning and 90 °F (32 °C) in the afternoon. The average January temperature is 18 °F (−8 °C) in the morning and 48 °F (9 °C) in the afternoon, although variation between consecutive days can be 40 °F (22 °C). Just west of

15372-615: Was datable material, converting the old relative ages into new absolute ages. For many geological applications, isotope ratios of radioactive elements are measured in minerals that give the amount of time that has passed since a rock passed through its particular closure temperature , the point at which different radiometric isotopes stop diffusing into and out of the crystal lattice . These are used in geochronologic and thermochronologic studies. Common methods include uranium–lead dating , potassium–argon dating , argon–argon dating and uranium–thorium dating . These methods are used for

15498-624: Was discovered at Dry Mesa by Ed and Vivian Jones of Delta, Colorado. The find was reported to James A. Jensen of Brigham Young University (BYU) who commenced quarrying operations in 1972. In 1973, Brigham Young University cooperated with producer Steve Linton and director John Linton in order to produce The Great Dinosaur Discovery , a 1-hour-long color documentary showing Jensen's on-site finds in Dry Mesa. First released on November 13, 1973, in local "Egyptian Theater" in Delta, and subsequently aired on several USA TV channels, The Great Dinosaur Discovery

15624-486: Was held in Colorado in March 1969. In 1967, Colorado was the first state to loosen restrictions on abortion when governor John Love signed a law allowing abortions in cases of rape, incest, or threats to the woman's mental or physical health. Many states followed Colorado's lead in loosening abortion laws in the 1960s and 1970s. Since the late 1990s, Colorado has been the site of multiple major mass shootings , including

15750-495: Was originally planned to be trimmed to about 30 minutes for educational use. Indeed, to obtain a shortened educational version, the full-length documentary was reduced to a 24-minute-long mini-film which started airing on American television channels throughout the USA as of 1976. During the four years that spanned from 1972 to 1976, rocks and fossils were stocked at the BYU football stadium until

15876-418: Was to the east-northeast. Geologic and taphonomic characteristics indicate a short transport distance for the bone accumulation (Richmond and Morris, 1999). Colorado The region has been inhabited by Native Americans and their ancestors for at least 13,500 years and possibly much longer. The eastern edge of the Rocky Mountains was a major migration route for early peoples who spread throughout

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