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124-476: The park consists of 310.31 km (76,680 acres; 119.81 sq mi; 31,031 ha) of high desert located on the Colorado Plateau . The highest elevation in the park is 5,653 ft (1,723 m) at Elephant Butte , and the lowest elevation is 4,085 ft (1,245 m) at the visitor center. The park receives an average of less than 10 in (250 mm) of rain annually. Administered by

248-523: A cold semi-arid climate ( BSk ). Humans have occupied the region since the last ice age 10,000 years ago. Fremont people and Ancestral Puebloans lived in the area until about 700 years ago. Spanish missionaries encountered Ute and Paiute tribes in the area when they first came through in 1775, but the first European-Americans to attempt settlement in the area were the Mormon Elk Mountain Mission in 1855, who soon abandoned

372-679: A continental margin throughout the late Precambrian and most of the Paleozoic era. Igneous rocks injected millions of years later form a marbled network through parts of the Colorado Plateau's darker metamorphic basement. By 600 million years ago North America had been leveled off to a remarkably smooth surface. Throughout the Paleozoic Era, tropical seas periodically inundated the Colorado Plateau region. Thick layers of limestone, sandstone, siltstone, and shale were laid down in

496-401: A cooler, wetter climate. This increased erosion at higher elevations with the introduction of alpine glaciers while mid-elevations were attacked by frost wedging and lower areas by more vigorous stream scouring. Pluvial lakes also formed during this time. Glaciers and pluvial lakes disappeared and the climate warmed and became drier with the start of Holocene epoch. The Colorado Plateau

620-588: A dissected limestone pavement . This process is most effective along the joints, widening and deepening them. In unpolluted environments, the pH of rainwater due to dissolved carbon dioxide is around 5.6. Acid rain occurs when gases such as sulfur dioxide and nitrogen oxides are present in the atmosphere. These oxides react in the rain water to produce stronger acids and can lower the pH to 4.5 or even 3.0. Sulfur dioxide , SO 2 , comes from volcanic eruptions or from fossil fuels, and can become sulfuric acid within rainwater, which can cause solution weathering to

744-675: A five-month out-and-back trip through much of the Plateau in 1776–1777. Despite having lost one arm in the American Civil War , U.S. Army Major and geologist John Wesley Powell explored the area in 1869 and 1872. Using wooden oak boats and small groups of men, the Powell Geographic Expedition charted this largely unknown region of the United States for the federal government. Construction of

868-691: A mineral crystal exposes ions whose electrical charge attracts water molecules. Some of these molecules break into H+ that bonds to exposed anions (usually oxygen) and OH- that bonds to exposed cations. This further disrupts the surface, making it susceptible to various hydrolysis reactions. Additional protons replace cations exposed on the surface, freeing the cations as solutes. As cations are removed, silicon-oxygen and silicon-aluminium bonds become more susceptible to hydrolysis, freeing silicic acid and aluminium hydroxides to be leached away or to form clay minerals. Laboratory experiments show that weathering of feldspar crystals begins at dislocations or other defects on

992-418: A more humid chemical microenvironment. The attachment of these organisms to the rock surface enhances physical as well as chemical breakdown of the surface microlayer of the rock. Lichens have been observed to pry mineral grains loose from bare shale with their hyphae (rootlike attachment structures), a process described as plucking , and to pull the fragments into their body, where the fragments then undergo

1116-584: A presidential proclamation creating the Arches National Monument, consisting of two comparatively small, disconnected sections. The purpose of the reservation under the 1906 Antiquities Act was to protect the arches, spires, balanced rocks, and other sandstone formations for their scientific and educational value. The name Arches was suggested by Frank Pinkely, superintendent of the Park Service's southwestern national monuments, following

1240-403: A process of chemical weathering not unlike digestion. On a larger scale, seedlings sprouting in a crevice and plant roots exert physical pressure as well as providing a pathway for water and chemical infiltration. Most rock forms at elevated temperature and pressure, and the minerals making up the rock are often chemically unstable in the relatively cool, wet, and oxidizing conditions typical of

1364-633: A proclamation substantially enlarging the Arches. Two years later, President Richard Nixon signed legislation enacted by Congress , which significantly reduced the total area enclosed, but changed its status. Arches National Park was formally dedicated in May 1972. In 1980, vandals attempted to use an abrasive kitchen cleanser to deface ancient petroglyphs in the park, prompting park officials to recruit physicist John F. Asmus , who specialized in using lasers to restore works of art, to use his technology to repair

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1488-454: A result of uplift bending the rock units. Eroded monoclines leave steeply tilted resistant rock called a hogback and the less steep version is a cuesta. Great tension developed in the crust, probably related to changing plate motions far to the west. As the crust stretched, the Basin and Range Province broke up into a multitude of down-dropped valleys and elongate mountains. Major faults, such as

1612-477: A result, thermal stress weathering is sometimes called insolation weathering , but this is misleading. Thermal stress weathering can be caused by any large change of temperature, and not just intense solar heating. It is likely as important in cold climates as in hot, arid climates. Wildfires can also be a significant cause of rapid thermal stress weathering. The importance of thermal stress weathering has long been discounted by geologists, based on experiments in

1736-659: A seaway along the passive western edge of the continent in the early Paleozoic. At the canyon rim is the Kaibab Formation, limestone deposited in the late Paleozoic (Permian) about 270 million years ago. A 12,000-to-15,000-foot high (3,700 to 4,600 m) extension of the Ancestral Rocky Mountains called the Uncompahgre Mountains were uplifted and the adjacent Paradox Basin subsided. Almost 4 mi. (6.4 km) of sediment from

1860-407: A slower reaction kinetics , this process is thermodynamically favored at low temperature, because colder water holds more dissolved carbon dioxide gas (due to the retrograde solubility of gases). Carbonate dissolution is therefore an important feature of glacial weathering. Carbonate dissolution involves the following steps: Carbonate dissolution on the surface of well-jointed limestone produces

1984-469: A threat to the environment and occupant safety. Design strategies can moderate the impact of environmental effects, such as using of pressure-moderated rain screening, ensuring that the HVAC system is able to effectively control humidity accumulation and selecting concrete mixes with reduced water content to minimize the impact of freeze-thaw cycles. Granitic rock, the most abundant crystalline rock exposed at

2108-570: A vertical pothole formation meets a horizontal cave , causing a union into a long arch structure. The erosion process within Arches National Park will continue as time continues to pass. Continued erosion combined with vertical and horizontal stress will eventually cause arches to collapse, but still, new arches will continue to form for thousands of years. According to the Köppen climate classification system, Arches Visitor Center has

2232-478: A visit to the Windows section in 1925. In late 1938, President Franklin D. Roosevelt signed a proclamation that enlarged the Arches to protect additional scenic features and permit the development of facilities to promote tourism. A small adjustment was made by President Dwight Eisenhower in 1960 to accommodate a new road alignment. In early 1969, just before leaving office, President Lyndon B. Johnson signed

2356-426: Is acid hydrolysis , in which protons (hydrogen ions), which are present in acidic water, attack chemical bonds in mineral crystals. The bonds between different cations and oxygen ions in minerals differ in strength, and the weakest will be attacked first. The result is that minerals in igneous rock weather in roughly the same order in which they were originally formed ( Bowen's Reaction Series ). Relative bond strength

2480-550: Is 14 megapascals (2,000 psi). This is still much greater than the tensile strength of granite, which is about 4 megapascals (580 psi). This makes frost wedging, in which pore water freezes and its volumetric expansion fractures the enclosing rock, appear to be a plausible mechanism for frost weathering. Ice will simply expand out of a straight open fracture before it can generate significant pressure. Thus, frost wedging can only take place in small tortuous fractures. The rock must also be almost completely saturated with water, or

2604-537: Is a physiographic and desert region of the Intermontane Plateaus , roughly centered on the Four Corners region of the southwestern United States . This plateau covers an area of 336,700 km (130,000 mi ) within western Colorado , northwestern New Mexico , southern and eastern Utah , northern Arizona , and a tiny fraction in the extreme southeast of Nevada . About 90% of the area

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2728-403: Is a less well characterized mechanism of physical weathering. It takes place because ice grains always have a surface layer, often just a few molecules thick, that resembles liquid water more than solid ice, even at temperatures well below the freezing point. This premelted liquid layer has unusual properties, including a strong tendency to draw in water by capillary action from warmer parts of

2852-626: Is a volcanic structure with a history similar to that of the San Francisco Peaks: a basalt flow closer to Grants was extruded only about 3000 years ago (see El Malpais National Monument ). These young igneous rocks may record processes in the Earth's mantle that are eating away at deep margins of the relatively stable block of the Plateau. Tectonic activity resumed in Mid Cenozoic time and started to unevenly uplift and slightly tilt

2976-440: Is also important, acting to oxidize many minerals, as is carbon dioxide, whose weathering reactions are described as carbonation . The process of mountain block uplift is important in exposing new rock strata to the atmosphere and moisture, enabling important chemical weathering to occur; significant release occurs of Ca and other ions into surface waters. Dissolution (also called simple solution or congruent dissolution )

3100-715: Is also known as sheeting . As with thermal weathering, pressure release is most effective in buttressed rock. Here the differential stress directed toward the unbuttressed surface can be as high as 35 megapascals (5,100 psi), easily enough to shatter rock. This mechanism is also responsible for spalling in mines and quarries, and for the formation of joints in rock outcrops. Retreat of an overlying glacier can also lead to exfoliation due to pressure release. This can be enhanced by other physical wearing mechanisms. Salt crystallization (also known as salt weathering , salt wedging or haloclasty ) causes disintegration of rocks when saline solutions seep into cracks and joints in

3224-507: Is also popular in the park due to its dark skies, despite the increasing light pollution from towns such as Moab. Delicate Arch is the subject of the third 2014 quarter of the U.S. Mint's America the Beautiful Quarters program commemorating national parks and historic sites. The Arches quarter had the highest production of the five 2014 national park quarters, with more than 465 million minted. American writer Edward Abbey

3348-426: Is banned by park regulations. Climbing on other features in the park is allowed but regulated; in addition, slacklining and BASE jumping are banned parkwide. Climbing on named arches within the park had long been banned by park regulations, but following Dean Potter 's successful free climb on Delicate Arch in May 2006, the wording of the regulations was deemed unenforceable by the park attorney . In response,

3472-612: Is chemically weathered to iron(II) sulfate and gypsum , which then crystallize as salt lenses. Salt crystallization can take place wherever salts are concentrated by evaporation. It is thus most common in arid climates where strong heating causes strong evaporation and along coasts. Salt weathering is likely important in the formation of tafoni , a class of cavernous rock weathering structures. Living organisms may contribute to mechanical weathering, as well as chemical weathering (see § Biological weathering below). Lichens and mosses grow on essentially bare rock surfaces and create

3596-421: Is covered with dry grasslands and shrublands, open pinyon-juniper woodland , and mountain woodlands and forests. Electrical power generation is one of the major industries that takes place in the Colorado Plateau region. Most electrical generation comes from coal fired power plants. The rocks of the Colorado Plateau are a source of oil and a major source of natural gas . Major petroleum deposits are present in

3720-718: Is drained by the Colorado River and its main tributaries : the Green , San Juan , and Little Colorado . Most of the remainder of the plateau is drained by the Rio Grande and its tributaries. The Colorado Plateau is largely made up of high desert, with scattered areas of forests. In the south-west corner of the Colorado Plateau lies the Grand Canyon of the Colorado River. Much of the Plateau's landscape

3844-403: Is found throughout southeastern Utah. The fibrous growths help keep soil particles together, creating a layer that is more resistant to erosion. The living soil layer readily absorbs and stores water, allowing more complex forms of plant life to grow in places with low precipitation levels. Among the notable features of the park are the following: Colorado Plateau The Colorado Plateau

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3968-577: Is in equilibrium with kaolinite. Soil formation requires between 100 and 1,000 years, a brief interval in geologic time. As a result, some formations show numerous paleosol (fossil soil) beds. For example, the Willwood Formation of Wyoming contains over 1,000 paleosol layers in a 770 meters (2,530 ft) section representing 3.5 million years of geologic time. Paleosols have been identified in formations as old as Archean (over 2.5 billion years in age). They are difficult to recognize in

4092-472: Is likely the more important mechanism in nature. Geomorphologists have begun to reemphasize the importance of thermal stress weathering, particularly in cold climates. Pressure release or unloading is a form of physical weathering seen when deeply buried rock is exhumed . Intrusive igneous rocks, such as granite , are formed deep beneath the Earth's surface. They are under tremendous pressure because of

4216-679: Is not a natural lake but a reservoir impounded by Glen Canyon Dam . National parks (from south to north to south clockwise): National monuments (alphabetical): Wilderness areas (alphabetical): Other notable protected areas include: Barringer Crater , Dead Horse Point State Park , Glen Canyon National Recreation Area , Goblin Valley State Park , Goosenecks State Park , the Grand Gulch Primitive Area , Kodachrome Basin State Park , Monument Valley , and

4340-503: Is related to the Grand Canyon in both appearance and geologic history. The nickname "Red Rock Country" suggests the brightly colored rock left bare to the view by dryness and erosion. Domes , hoodoos , fins , reefs , river narrows , natural bridges , and slot canyons are only some of the additional features typical of the Plateau. The Colorado Plateau has the greatest concentration of U.S. National Park Service (NPS) units in

4464-484: Is relatively poor in potassium, the basalt weathers directly to potassium-poor montmorillonite , then to kaolinite . Where leaching is continuous and intense, as in rain forests, the final weathering product is bauxite , the principal ore of aluminium. Where rainfall is intense but seasonal, as in monsoon climates, the final weathering product is iron- and titanium-rich laterite . Conversion of kaolinite to bauxite occurs only with intense leaching, as ordinary river water

4588-449: Is shown in the following table: This table is only a rough guide to order of weathering. Some minerals, such as illite , are unusually stable, while silica is unusually unstable given the strength of the silicon–oxygen bond . Carbon dioxide that dissolves in water to form carbonic acid is the most important source of protons, but organic acids are also important natural sources of acidity. Acid hydrolysis from dissolved carbon dioxide

4712-421: Is sometimes described as carbonation , and can result in weathering of the primary minerals to secondary carbonate minerals. For example, weathering of forsterite can produce magnesite instead of brucite via the reaction: Carbonic acid is consumed by silicate weathering, resulting in more alkaline solutions because of the bicarbonate . This is an important reaction in controlling the amount of CO 2 in

4836-410: Is the class of processes that causes the disintegration of rocks without chemical change. Physical weathering involves the breakdown of rocks into smaller fragments through processes such as expansion and contraction, mainly due to temperature changes. Two types of physical breakdown are freeze-thaw weathering and thermal fracturing. Pressure release can also cause weathering without temperature change. It

4960-483: Is the deterioration of rocks , soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases , sunlight , and biological organisms. It occurs in situ (on-site, with little or no movement), and so is distinct from erosion , which involves the transport of rocks and minerals by agents such as water , ice , snow , wind , waves and gravity . Weathering processes are either physical or chemical. The former involves

5084-474: Is the main cause of the formation of the arches, spires, balanced rocks, sandstone fins , and eroded monoliths in the area. This salt bed is thousands of feet thick in places and was deposited in the Paradox Basin of the Colorado Plateau some 300 million years ago (Mya) when a sea flowed into the region and eventually evaporated. Over millions of years, the salt bed was covered with debris eroded from

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5208-417: Is the process in which a mineral dissolves completely without producing any new solid substance. Rainwater easily dissolves soluble minerals, such as halite or gypsum , but can also dissolve highly resistant minerals such as quartz , given sufficient time. Water breaks the bonds between atoms in the crystal: [REDACTED] The overall reaction for dissolution of quartz is The dissolved quartz takes

5332-410: Is to protect extraordinary examples of geologic features including arches, natural bridges, windows, spires, and balanced rocks, as well as other features of geologic, historic, and scientific interest, and to provide opportunities to experience these resources and their associated values in their majestic natural settings. The national park lies above an underground evaporite layer or salt bed, which

5456-431: Is usually much less important than chemical weathering, but can be significant in subarctic or alpine environments. Furthermore, chemical and physical weathering often go hand in hand. For example, cracks extended by physical weathering will increase the surface area exposed to chemical action, thus amplifying the rate of disintegration. Frost weathering is the most important form of physical weathering. Next in importance

5580-426: Is wedging by plant roots, which sometimes enter cracks in rocks and pry them apart. The burrowing of worms or other animals may also help disintegrate rock, as can "plucking" by lichens. Frost weathering is the collective name for those forms of physical weathering that are caused by the formation of ice within rock outcrops. It was long believed that the most important of these is frost wedging , which results from

5704-726: The Hoover Dam in the 1930s and the Glen Canyon Dam in the 1960s changed the character of the Colorado River. Dramatically reduced sediment load changed its color from reddish brown ( Colorado is Spanish for "red-colored") to mostly clear. The apparent green color is from algae on the riverbed's rocks, not from any significant amount of suspended material. The lack of sediment has also starved sand bars and beaches, but an experimental 12-day-long controlled flood from Glen Canyon Dam in 1996 showed substantial restoration. Similar floods are planned for every 5 to 10 years. One of

5828-456: The Mesozoic era the region was affected by a series of orogenies ( mountain -building events) that deformed western North America and caused a great deal of uplift. Eruptions from volcanic mountain ranges to the west buried vast regions beneath ashy debris. Short-lived rivers, lakes, and inland seas left sedimentary records of their passage. Streams, ponds and lakes produced formations such as

5952-537: The National Park Service , the area was originally named a national monument on April 12, 1929, and was redesignated as a national park on November 12, 1971. The park received more than 1.8 million visitors in 2021. From April 1 through October 31, a timed entry reservation is required to visit the park between the hours of 7 a.m. and 4 p.m. As stated in the foundation document in U.S. National Park Service website: The purpose of Arches National Park

6076-666: The San Juan Basin of New Mexico and Colorado, the Uinta Basin of Utah, the Piceance Basin of Colorado, and the Paradox Basin of Utah, Colorado, and Arizona. The Colorado Plateau holds major uranium deposits, and there was a uranium boom in the 1950s. The Atlas Uranium Mill near Moab has left a problematic tailings pile for cleanup. As of 2019 , 10 million tons of tailings had been relocated out of an estimated 16 million tons. Major coal deposits are being mined in

6200-586: The San Rafael Swell . Sedona, Arizona and Oak Creek Canyon lie on the south-central border of the Plateau. Many but not all of the Sedona area's cliff formations are protected as wilderness ( Red Rock State Park and Coconino National Forest ). The area has the visual appeal of a national park, but with a small, rapidly growing town in the center. 37°N 110°W  /  37°N 110°W  / 37; -110 Weathering Weathering

6324-862: The Southern Rocky Mountains , such as the San Juan Mountains in Colorado and the La Sal Mountains in Utah, intermix into the central and southern parts of the Colorado Plateau. It is composed of six sections: As the name implies, the High Plateaus Section is, on average, the highest section. North-south trending normal faults that include the Hurricane , Sevier, Grand Wash , and Paunsaugunt separate

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6448-671: The Uncompahgre Uplift to the northeast. During the Early Jurassic (about 200 Mya), desert conditions prevailed in the region and the vast Navajo Sandstone was deposited. An additional sequence of stream laid and windblown sediments, the Entrada Sandstone (about 140 Mya), was deposited on top of the Navajo. Over 5,000 feet (1,500 m) of younger sediments were deposited and have been mostly eroded. Remnants of

6572-668: The Wasatch Line and its various faults form the province's western edge. Faults that run parallel to the Wasatch Fault that lies along the Wasatch Range form the boundaries between the plateaus in the High Plateaus Section. The Uinta Basin, Uncompahgre Uplift, and the Paradox Basin were also formed by movement along structural weaknesses in the region's oldest rock. In Utah, the province includes several higher fault-separated plateaus : Some sources also include

6696-795: The country outside the Washington, DC metropolitan area. Among its nine national parks are Grand Canyon , Zion , Bryce Canyon , Capitol Reef , Canyonlands , Arches , Black Canyon , Mesa Verde , and Petrified Forest . Among its 18 national monuments and other protected areas managed by the NPS, the United States Forest Service , and the Bureau of Land Management are Bears Ears , Rainbow Bridge , Dinosaur , Hovenweep , Wupatki , Sunset Crater Volcano , Grand Staircase–Escalante , El Malpais , Natural Bridges , Canyons of

6820-547: The pueblos of the Ancestral Puebloan culture. There are nine U.S. National Parks , a National Historical Park, nineteen U.S. national monuments and dozens of wilderness areas in the province along with millions of acres in U.S. National Forests , many state parks, and other protected lands. In fact, this region has the highest concentration of parklands in North America. Lake Powell , in foreground,

6944-520: The rock formations have weaker layers of rock on bottom that are holding stronger layers on top. The weaker layers would dissolve first, creating openings in the rock. Gravity caused pieces of the stronger rock layer to fall piece by piece into an arch shape. Arches form within rock fins at points of intense fracturing localization, or weak points in the rock's formation, caused by horizontal and vertical discontinuities. Lastly, water, wind, and time continued this erosion process and ultimately created

7068-841: The Ancients , Chaco Culture National Historical Park and the Colorado National Monument . This province is bounded by the Rocky Mountains in Colorado and by the Uinta Mountains and Wasatch Mountains branches of the Rockies in northern and central Utah. It is also bounded by the Rio Grande rift , Mogollon Rim , and the Basin and Range Province (at the Hurricane Fault ). Isolated ranges of

7192-605: The Basin and Range means that the Colorado Plateau receives six to sixteen inches (15 to 40 cm) of annual precipitation. Higher areas receive more precipitation and are covered in forests of pine, fir, and spruce. Though it can be said that the Plateau roughly centers on the Four Corners, Black Mesa in northern Arizona is much closer to the east–west, north–south midpoint of the Plateau Province. Lying southeast of Glen Canyon and southwest of Monument Valley at

7316-742: The Chinle, Moenave, and Kayenta in the Mesozoic era. Later a vast desert formed the Navajo and Temple Cap formations and dry near-shore environment formed the Carmel (see geology of the Zion and Kolob canyons area for details). The area was again covered by a warm shallow sea when the Cretaceous Seaway opened in late Mesozoic time. The Dakota Sandstone and the Tropic Shale were deposited in

7440-540: The Colorado Plateau in Utah, Arizona, Colorado, and New Mexico, though large coal mining projects, such as on the Kaiparowits Plateau , have been proposed and defeated politically. The ITT Power Project, eventually located in Lynndyl, Utah , near Delta, was originally suggested for Salt Wash near Capitol Reef National Park. After a firestorm of opposition, it was moved to a less controversial site. In Utah

7564-466: The Colorado Plateau region and the region to the west some 20 million years ago (as much as 3 kilometers of uplift occurred). Streams had their gradient increased and they responded by downcutting faster. Headward erosion and mass wasting helped to erode cliffs back into their fault-bounded plateaus, widening the basins in-between. Some plateaus have been so severely reduced in size this way that they become mesas or even buttes . Monoclines form as

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7688-408: The Earth's surface, begins weathering with the destruction of hornblende . Biotite then weathers to vermiculite , and finally oligoclase and microcline are destroyed. All are converted into a mixture of clay minerals and iron oxides. The resulting soil is depleted in calcium, sodium, and ferrous iron compared with the bedrock, and magnesium is reduced by 40% and silicon by 15%. At the same time,

7812-411: The Earth's surface. Chemical weathering takes place when water, oxygen, carbon dioxide, and other chemical substances react with rock to change its composition. These reactions convert some of the original primary minerals in the rock to secondary minerals, remove other substances as solutes, and leave the most stable minerals as a chemically unchanged resistate . In effect, chemical weathering changes

7936-538: The Grand Staircase extend north of the Grand Canyon and are named for their color: Within these rocks are abundant mineral resources, including uranium, coal, petroleum, and natural gas. A study of the area's unusually clear geologic history (laid bare due to the arid and semiarid conditions) has greatly advanced that science. A rain shadow from the Sierra Nevada far to the west and the many ranges of

8060-501: The Hurricane Fault, developed that separate the two regions. The dry climate was in large part a rainshadow effect resulting from the rise of the Sierra Nevada further west. Yet for some reason not fully understood, the neighboring Colorado Plateau was able to preserve its structural integrity and remained a single tectonic block. A second mystery was that while the lower layers of the Plateau appeared to be sinking, overall

8184-749: The Navajo Volcanic Field, produced about 25 million years ago. The Hopi Buttes in northeastern Arizona are held up by resistant sheets of sodic volcanic rocks, extruded about 7 million years ago. More recent igneous rocks are concentrated nearer the margins of the Colorado Plateau. The San Francisco Peaks near Flagstaff , south of the Grand Canyon , are volcanic landforms produced by igneous activity that began in that area about 6 million years ago and continued until 1064 CE, when basalt erupted in Sunset Crater National Monument . Mount Taylor , near Grants, New Mexico ,

8308-607: The Plateau was rising. The reason for this was discovered upon analyzing data from the USARRAY project. It was found that the asthenosphere had invaded the overlying lithosphere , as a result of an area of mantle upwelling stemming from either the disintegration of the descending Farallon Plate , or the survival of the subducted spreading center connected to the East Pacific Rise and Gorda Ridge beneath western North America, or possibly both. The asthenosphere erodes

8432-604: The Tushar Mountain Plateau as part of the Colorado Plateau, but others do not. The mostly flat-lying sedimentary rock units that make up these plateaus are found in component plateaus that are between 4,900 to 11,000 feet (1,500 to 3,350 m) above sea level. A supersequence of these rocks is exposed in the various cliffs and canyons (including the Grand Canyon ) that make up the Grand Staircase . Increasingly younger east–west trending escarpments of

8556-409: The affected rocks a reddish-brown coloration on the surface which crumbles easily and weakens the rock. Many other metallic ores and minerals oxidize and hydrate to produce colored deposits, as does sulfur during the weathering of sulfide minerals such as chalcopyrites or CuFeS 2 oxidizing to copper hydroxide and iron oxides . Mineral hydration is a form of chemical weathering that involves

8680-455: The arches form, and the buff-colored Navajo Sandstone. These are visible in layer-cake fashion throughout most of the park. Over time, water seeped into the surface cracks, joints, and folds of these layers. Ice formed in the fissures, expanding and putting pressure on surrounding rock, breaking off bits and pieces. Winds later cleaned out the loose particles. A series of free-standing fins remained. Wind and water attacked these fins until, in some,

8804-505: The arches of Arches National Park. All of the arches in the park are made of Entrada Sandstone, however, there are slight differences in how each arch was developed. Entrada Sandstone is categorized into three groups: Slick rock members , Dewey rock members, and Moab members . Vertical arches can be developed from Slick rock members, a combination of Slick rock members and Moab members, or Slick rock members resting above Dewey rock members. Horizontal arches (also called potholes) are formed when

8928-425: The area be made a national monument. The following year, additional support for the monument idea came from Laurence Gould , a University of Michigan graduate student (and future polar explorer) studying the geology of the nearby La Sal Mountains , who was shown the scenic area by local physician Dr. J. W. "Doc" Williams. A succession of government investigators examined the area, in part due to confusion as to

9052-727: The area in September 1923 at the invitation of Alexander Ringhoffer, a Hungarian -born prospector living in Salt Valley. Ringhoffer had written to the railroad to interest them in the tourist potential of a scenic area he had discovered the previous year with his two sons and a son-in-law, which he called the Devils Garden (known today as the Klondike Bluffs). Wadleigh was impressed by what Ringhoffer showed him, and suggested to Park Service director Stephen T. Mather that

9176-614: The area. Ranchers, farmers, and prospectors later settled Moab in the neighboring Riverine Valley in the late 1870s. Word of the beauty of the surrounding rock formations spread beyond the settlement as a possible tourist destination. The Arches area was first brought to the attention of the National Park Service by Frank A. Wadleigh, passenger traffic manager of the Denver and Rio Grande Western Railroad . Wadleigh, accompanied by railroad photographer George L. Beam, visited

9300-501: The areas between the domes. In some places, they turned almost on edge. The result of one such 2,500 ft (760 m) displacement, the Moab Fault , is seen from the visitor center. As this subsurface movement of salt shaped the landscape, erosion removed the younger rock layers from the surface. Except for isolated remnants, the major formations visible in the park today are the salmon-colored Entrada Sandstone, in which most of

9424-466: The atmosphere and can affect climate. Aluminosilicates containing highly soluble cations, such as sodium or potassium ions, will release the cations as dissolved bicarbonates during acid hydrolysis: Within the weathering environment, chemical oxidation of a variety of metals occurs. The most commonly observed is the oxidation of Fe ( iron ) by oxygen and water to form Fe oxides and hydroxides such as goethite , limonite , and hematite . This gives

9548-463: The breakdown of rocks and soils through such mechanical effects as heat, water, ice and wind. The latter covers reactions to water, atmospheric gases and biologically produced chemicals with rocks and soils. Water is the principal agent behind both kinds, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Biological chemical weathering is also called biological weathering. The materials left after

9672-819: The carbon dioxide level to 30% of all soil gases, aided by adsorption of CO 2 on clay minerals and the very slow diffusion rate of CO 2 out of the soil. The CO 2 and organic acids help break down aluminium - and iron -containing compounds in the soils beneath them. Roots have a negative electrical charge balanced by protons in the soil next to the roots, and these can be exchanged for essential nutrient cations such as potassium. Decaying remains of dead plants in soil may form organic acids which, when dissolved in water, cause chemical weathering. Chelating compounds, mostly low molecular weight organic acids, are capable of removing metal ions from bare rock surfaces, with aluminium and silicon being particularly susceptible. The ability to break down bare rock allows lichens to be among

9796-413: The cementing material gave way and chunks of rock tumbled out. Many damaged fins collapsed. Others, with the right degree of hardness and balance, survived despite their missing sections. These became the famous arches. Although the park's terrain may appear rugged and durable, it is extremely fragile. More than 1 million visitors each year threaten the fragile high-desert ecosystem. The problem lies within

9920-560: The cover exist in the area including exposures of the Cretaceous Mancos Shale . The arches of the area are developed mostly within the Entrada formation. The weight of this cover caused the salt bed below it to liquefy and thrust up layers of rock into salt domes . The evaporites of the area formed more unusual "salt anticlines " or linear regions of uplift. Faulting occurred and whole sections of rock subsided into

10044-466: The damage. Asmus "zapped the panel with intense light pulses and succeeded in removing most of the cleanser". In 2016, there was another vandalism event on Frame Arch in the park, where a section of the rock was carved out. Due to advances in technology, in 2018 the arch was repaired through color match and modern infilling methods. Climbing Balanced Rock or any named or unnamed arch in Arches National Park with an opening larger than 3 ft (0.9 m)

10168-530: The early 20th century that seemed to show that its effects were unimportant. These experiments have since been criticized as unrealistic, since the rock samples were small, were polished (which reduces nucleation of fractures), and were not buttressed. These small samples were thus able to expand freely in all directions when heated in experimental ovens, which failed to produce the kinds of stress likely in natural settings. The experiments were also more sensitive to thermal shock than thermal fatigue, but thermal fatigue

10292-403: The edge of the salt bed continued to erode and shift into vertical sandstone walls called fins . Sand collected between vertical walls of the fins, then slightly acidic rain combined with carbon dioxide in the air allowed for the chemical formation of carbonic acid within the trapped sand. Over time, the carbonic acid dissolved the calcium carbonate that held the sandstone together. Many of

10416-427: The expansion of pore water when it freezes. A growing body of theoretical and experimental work suggests that ice segregation, whereby supercooled water migrates to lenses of ice forming within the rock, is the more important mechanism. When water freezes, its volume increases by 9.2%. This expansion can theoretically generate pressures greater than 200 megapascals (29,000 psi), though a more realistic upper limit

10540-404: The expense of silica, titanium, aluminum, ferrous iron, and calcium. Buildings made of any stone, brick or concrete are susceptible to the same weathering agents as any exposed rock surface. Also statues , monuments and ornamental stonework can be badly damaged by natural weathering processes. This is accelerated in areas severely affected by acid rain . Accelerated building weathering may be

10664-488: The first colonizers of dry land. The accumulation of chelating compounds can easily affect surrounding rocks and soils, and may lead to podsolisation of soils. The symbiotic mycorrhizal fungi associated with tree root systems can release inorganic nutrients from minerals such as apatite or biotite and transfer these nutrients to the trees, thus contributing to tree nutrition. It was also recently evidenced that bacterial communities can impact mineral stability leading to

10788-463: The form of silicic acid . A particularly important form of dissolution is carbonate dissolution, in which atmospheric carbon dioxide enhances solution weathering. Carbonate dissolution affects rocks containing calcium carbonate , such as limestone and chalk . It takes place when rainwater combines with carbon dioxide to form carbonic acid , a weak acid , which dissolves calcium carbonate (limestone) and forms soluble calcium bicarbonate . Despite

10912-669: The geologic record. Indications that a sedimentary bed is a paleosol include a gradational lower boundary and sharp upper boundary, the presence of much clay, poor sorting with few sedimentary structures, rip-up clasts in overlying beds, and desiccation cracks containing material from higher beds. The degree of weathering of soil can be expressed as the chemical index of alteration , defined as 100 Al 2 O 3 /(Al 2 O 3 + CaO + Na 2 O + K 2 O) . This varies from 47 for unweathered upper crust rock to 100 for fully weathered material. Wood can be physically and chemically weathered by hydrolysis and other processes relevant to minerals and

11036-439: The ice will simply expand into the air spaces in the unsaturated rock without generating much pressure. These conditions are unusual enough that frost wedging is unlikely to be the dominant process of frost weathering. Frost wedging is most effective where there are daily cycles of melting and freezing of water-saturated rock, so it is unlikely to be significant in the tropics, in polar regions or in arid climates. Ice segregation

11160-468: The interval from 20 to 31 million years: some igneous intrusions in these mountains form laccoliths , a form of intrusion recognized by Grove Karl Gilbert during his studies of the Henry Mountains . Ship Rock (also called Shiprock ), in northwestern New Mexico, and Church Rock and Agathla , near Monument Valley , are erosional remnants of potassium-rich igneous rocks and associated breccias of

11284-739: The largest deposits are in aptly named Carbon County. In Arizona the biggest operation is on Black Mesa , supplying coal to Navajo Power Plant. Perhaps the only one of its kind, a gilsonite plant near Bonanza, southeast of Vernal, Utah , mines this unique, lustrous, brittle form of asphalt, for use in "varnishes, paints,...ink, waterproofing compounds, electrical insulation,...roofing materials." This relatively high, semi-arid to arid province produces many distinctive erosional features such as arches, arroyos , canyons, cliffs, fins, natural bridges , pinnacles, hoodoos , and monoliths that, in various places and extents, have been protected. Also protected are areas of historic or cultural significance, such as

11408-488: The lower levels of the Plateau. At the same time, as it cools, it expands and lifts the upper layers of the Plateau. Eventually, the great block of Colorado Plateau crust rose a kilometer higher than the Basin and Range. As the land rose, the streams responded by cutting ever deeper stream channels. The most well-known of these streams, the Colorado River , began to carve the Grand Canyon less than 6 million years ago. The Pleistocene epoch brought periodic ice ages and

11532-546: The most effective biological agents of chemical weathering. For example, an experimental study on hornblende granite in New Jersey, US, demonstrated a 3x – 4x increase in weathering rate under lichen covered surfaces compared to recently exposed bare rock surfaces. The most common forms of biological weathering result from the release of chelating compounds (such as certain organic acids and siderophores ) and of carbon dioxide and organic acids by plants. Roots can build up

11656-506: The most geologically intriguing features of the Colorado Plateau is its remarkable stability. Relatively little rock deformation such as faulting and folding has affected this high, thick crustal block within the last 600 million years or so, although there are some newer features such as the Waterpocket Fold of Capitol Reef (estimated 50–70 million years old). In contrast, provinces that have suffered severe deformation surround

11780-462: The mountains and evaporites from the sea were deposited (see geology of the Canyonlands area for detail). Most of the formations were deposited in warm shallow seas and near-shore environments (such as beaches and swamps) as the seashore repeatedly advanced and retreated over the edge of a proto-North America (for detail, see geology of the Grand Canyon area ). The province was probably on

11904-597: The north end of the Hopi Reservation, this remote coal-laden highland has about half of the Colorado Plateau's acreage north of it, half south of it, half west of it, and half east of it. The American Association of Petroleum Geologists divides the Colorado Plateau into four geologic provinces. These are: The Ancestral Puebloan People lived in the region from roughly 2000 to 700 years ago. A party from Santa Fe led by Fathers Dominguez and Escalante , unsuccessfully seeking an overland route to California, made

12028-483: The oldest ages recorded by these rocks fall from 1950 to 1680 million years. An erosion surface on the Vishnu Basement Rocks is covered by sedimentary rocks and basalt flows, and these rocks formed in the interval from about 1250 to 750 million years ago: in turn, they were uplifted and split into a range of fault-block mountains . Erosion greatly reduced this mountain range before the encroachment of

12152-551: The original set of minerals in the rock into a new set of minerals that is in closer equilibrium with surface conditions. True equilibrium is rarely reached, because weathering is a slow process, and leaching carries away solutes produced by weathering reactions before they can accumulate to equilibrium levels. This is particularly true in tropical environments. Water is the principal agent of chemical weathering, converting many primary minerals to clay minerals or hydrated oxides via reactions collectively described as hydrolysis . Oxygen

12276-443: The overlying rock material. When erosion removes the overlying rock material, these intrusive rocks are exposed and the pressure on them is released. The outer parts of the rocks then tend to expand. The expansion sets up stresses which cause fractures parallel to the rock surface to form. Over time, sheets of rock break away from the exposed rocks along the fractures, a process known as exfoliation . Exfoliation due to pressure release

12400-406: The park revised its regulations later that month, eventually imposing the current ban on arch climbing in 2014. Approved recreational activities include auto touring, hiking, bicycling, camping at the Devils Garden campground, backpacking, canyoneering , and rock climbing, with permits required for the last three activities. Guided commercial tours and ranger programs are also available. Astronomy

12524-778: The park. An abundance of wildlife occurs in Arches National Park, including spadefoot toads , antelope squirrels , scrub jays , peregrine falcons , many kinds of sparrows , red foxes , desert bighorn sheep , kangaroo rats , mule deers , cougars , midget faded rattlesnakes , yucca moths , western rattlesnakes , and collared lizards . A number of plant species are common in the park, including prickly pear cactus , Indian ricegrass , bunch grasses , cheatgrass , moss , liverworts , Utah juniper , Mormon tea , blackbrush , cliffrose , four-winged saltbrush , pinyon pine , evening primrose , sand verbena , yucca , and sacred datura . Biological soil crust consisting of cyanobacteria , lichen, mosses, green algae , and microfungi

12648-594: The plateau. Mountain building thrust up the Rocky Mountains to the north and east and tremendous, earth-stretching tension produced the Basin and Range Province to the west and south. Sub ranges of the Southern Rocky Mountains are scattered throughout the Colorado Plateau. The Precambrian and Paleozoic history of the Colorado Plateau is best revealed near its southern end, where the Grand Canyon has exposed rocks with ages that span almost 2 billion years. The oldest rocks at river level are igneous and metamorphic and have been lumped together as Vishnu Basement Rocks ;

12772-672: The precise location. In the process, the name Devils Garden was transposed to an area on the opposite side of Salt Valley that includes Landscape Arch , the longest arch in the park. Ringhoffer's original discovery was omitted, while another area nearby, known locally as the Windows, was included. Designation of the area as a national monument was supported by the Park Service in 1926 but was resisted by President Calvin Coolidge 's Interior Secretary, Hubert Work . Finally, in April 1929, shortly after his inauguration, President Herbert Hoover signed

12896-402: The production of weathering agents, such as protons, organic acids and chelating molecules. Weathering of basaltic oceanic crust differs in important respects from weathering in the atmosphere. Weathering is relatively slow, with basalt becoming less dense, at a rate of about 15% per 100 million years. The basalt becomes hydrated, and is enriched in total and ferric iron, magnesium, and sodium at

13020-464: The region, which acted as a rigid crustal block. The Colorado Plateau Province was uplifted largely as a single block, possibly due to its relative thickness. This relative thickness may be why compressional forces from the orogeny were mostly transmitted through the province instead of deforming it. Pre-existing weaknesses in Precambrian rocks were exploited and reactivated by the compression. It

13144-416: The release of inorganic nutrients. A large range of bacterial strains or communities from diverse genera have been reported to be able to colonize mineral surfaces or to weather minerals, and for some of them a plant growth promoting effect has been demonstrated. The demonstrated or hypothesised mechanisms used by bacteria to weather minerals include several oxidoreduction and dissolution reactions as well as

13268-448: The rigid attachment of water molecules or H+ and OH- ions to the atoms and molecules of a mineral. No significant dissolution takes place. For example, iron oxides are converted to iron hydroxides and the hydration of anhydrite forms gypsum . Bulk hydration of minerals is secondary in importance to dissolution, hydrolysis, and oxidation, but hydration of the crystal surface is the crucial first step in hydrolysis. A fresh surface of

13392-421: The rock breaks down combine with organic material to create soil . Many of Earth's landforms and landscapes are the result of weathering, erosion and redeposition. Weathering is a crucial part of the rock cycle ; sedimentary rock , the product of weathered rock, covers 66% of the Earth's continents and much of the ocean floor . Physical weathering , also called mechanical weathering or disaggregation ,

13516-455: The rock surface, which gradually pry the rock apart. Thermal stress weathering results from the expansion and contraction of rock due to temperature changes. Thermal stress weathering is most effective when the heated portion of the rock is buttressed by surrounding rock, so that it is free to expand in only one direction. Thermal stress weathering comprises two main types, thermal shock and thermal fatigue . Thermal shock takes place when

13640-413: The rock. This results in growth of the ice grain that puts considerable pressure on the surrounding rock, up to ten times greater than is likely with frost wedging. This mechanism is most effective in rock whose temperature averages just below the freezing point, −4 to −15 °C (25 to 5 °F). Ice segregation results in growth of ice needles and ice lenses within fractures in the rock and parallel to

13764-408: The rocks and evaporate, leaving salt crystals behind. As with ice segregation, the surfaces of the salt grains draw in additional dissolved salts through capillary action, causing the growth of salt lenses that exert high pressure on the surrounding rock. Sodium and magnesium salts are the most effective at producing salt weathering. Salt weathering can also take place when pyrite in sedimentary rock

13888-425: The rocks on which it falls. Hydrolysis (also called incongruent dissolution ) is a form of chemical weathering in which only part of a mineral is taken into solution. The rest of the mineral is transformed into a new solid material, such as a clay mineral . For example, forsterite (magnesium olivine ) is hydrolyzed into solid brucite and dissolved silicic acid: Most hydrolysis during weathering of minerals

14012-574: The sandstone is predominantly of eolian origin and locally more than 500 meters thick. The Chuska Sandstone caps the Chuska Mountains , and it lies unconformably on Mesozoic rocks deformed during the Laramide orogeny . Younger igneous rocks form spectacular topographic features. The Henry Mountains , La Sal Range , and Abajo Mountains , ranges that dominate many views in southeastern Utah, are formed about igneous rocks that were intruded in

14136-533: The section's component plateaus. This fault pattern is caused by the tensional forces pulling apart the adjacent Basin and Range Province to the west, making this section transitional. Occupying the southeast corner of the Colorado Plateau is the Datil Section. Thick sequences of mid- Tertiary to late- Cenozoic -aged lava covers this section. The development of the province has, in large part, been influenced by structural features in its oldest rocks. Part of

14260-462: The shallow marine waters. During times when the seas retreated, stream deposits and dune sands were deposited or older layers were removed by erosion. Over 300 million years passed as layer upon layer of sediment accumulated. It was not until the upheavals that coincided with the formation of the supercontinent Pangea began about 250 million years ago that deposits of marine sediment waned and terrestrial deposits dominate. In late Paleozoic and much of

14384-498: The soil are cytophobic soil crust index, measuring of water infiltration, and t-tests that are used to compare the values from the undisturbed and disturbed areas. Geological processes that occurred over 300 million years ago caused a salt bed to be deposited, which today lies beneath the landscape of Arches National Park. Over time, the salt bed was covered with sediments that eventually compressed into rock layers that have since been named Entrada Sandstone . Rock layers surrounding

14508-536: The soil is enriched in aluminium and potassium by at least 50%; by titanium, whose abundance triples, and ferric iron, whose abundance increases by an order of magnitude compared with the bedrock. Basaltic rock is more easily weathered than granitic rock due to its formation at higher temperatures and drier conditions. The fine grain size and presence of volcanic glass also hasten weathering. In tropical settings, it rapidly weathers to clay minerals, aluminium hydroxides, and titanium-enriched iron oxides. Because most basalt

14632-466: The soil's crust, which is composed of cyanobacteria , algae, fungi, and lichens that grow in the dusty parts of the park. Factors that make Arches National Park sensitive to visitor damage include being a semiarid region, the scarce, unpredictable rainfall, lack of deep freezing, and lack of plant litter, which results in soils that have both a low resistance to and slow recovery from, compressional forces such as foot traffic. Methods of indicating effects on

14756-517: The start of the Cenozoic era and were accompanied by some basaltic lava eruptions and mild deformation. The colorful Claron Formation that forms the delicate hoodoos of Bryce Amphitheater and Cedar Breaks was then laid down as sediments in cool streams and lakes (see geology of the Bryce Canyon area for details). The flat-lying Chuska Sandstone was deposited about 34 million years ago;

14880-419: The stresses are so great that the rock cracks immediately, but this is uncommon. More typical is thermal fatigue, in which the stresses are not great enough to cause immediate rock failure, but repeated cycles of stress and release gradually weaken the rock. Thermal stress weathering is an important mechanism in deserts , where there is a large diurnal temperature range, hot in the day and cold at night. As

15004-454: The surface of the crystal, and that the weathering layer is only a few atoms thick. Diffusion within the mineral grain does not appear to be significant. Mineral weathering can also be initiated or accelerated by soil microorganisms. Soil organisms make up about 10 mg/cm of typical soils, and laboratory experiments have demonstrated that albite and muscovite weather twice as fast in live versus sterile soil. Lichens on rocks are among

15128-423: The warm shallow waters of this advancing and retreating seaway. Several other formations were also produced but were mostly eroded following two major periods of uplift. The Laramide orogeny closed the seaway and uplifted a large belt of crust from Montana to Mexico, with the Colorado Plateau region being the largest block. Thrust faults in Colorado are thought to have formed from a slight clockwise movement of

15252-624: Was a park ranger at Arches National Monument in 1956 and 1957, where he kept journals that became his book Desert Solitaire . The success of Abbey's book, as well as interest in adventure travel , has drawn many hikers , mountain bikers , and off-pavement driving enthusiasts to the area. Permitted activities within the park include camping, hiking along designated trails, backpacking, canyoneering, rock climbing, bicycling, and driving along existing roads, both paved and unpaved. The Hayduke Trail , an 812 mi (1,307 km) backpacking route named after one of Edward Abbey's characters , begins in

15376-529: Was along these ancient faults and other deeply buried structures that much of the province's relatively small and gently inclined flexures (such as anticlines , synclines , and monoclines ) formed. Some of the prominent isolated mountain ranges of the Plateau, such as Ute Mountain and the Carrizo Mountains , both near the Four Corners , are cored by igneous rocks that were emplaced about 70 million years ago. Minor uplift events continued through

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