Misplaced Pages

#872127

59-402: As part of the southern Colorado Plateau ( Mogollon Plateau ) it has an average elevation of 4,000–5,000 feet. Physiographic Features National Monuments : Arizona State Parks Cities/Towns: 34°45′N 111°33′W  /  34.75°N 111.55°W  / 34.75; -111.55 Colorado Plateau The Colorado Plateau is a physiographic and desert region of

118-679: 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

177-401: 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

236-675: 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

295-454: 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

354-659: 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

413-530: A short distance into northwest Colorado and slightly into southwestern Wyoming in the United States . As a subrange of the Rocky Mountains , they are unusual for being the highest range in the contiguous United States running east to west, and lie approximately 100 miles (160 km) east of Salt Lake City . The range has peaks ranging from 11,000 to 13,528 feet (3,353 to 4,123 m), with

472-729: Is Mirror Lake because of its good fishing, scenic views, and easy road access. The south and east sides of the range are largely within the Colorado River watershed, including the Blacks Fork and the Duchesne River , which are tributaries of the Green River . The Green is the major tributary of the Colorado River and flows in a tight arc around the eastern side of the range. (Indeed, John Wesley Powell said

531-626: 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

590-421: 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

649-679: 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

SECTION 10

#1732787811873

708-721: Is typical of the central Rocky Mountains. Large grazing and browsing animals include the Rocky Mountain elk, mule deer, moose, pronghorn antelope, mountain goats, and Rocky Mountain bighorn sheep. Mammalian predators include the American black bear, mountain lion, coyotes, red fox, badger, wolverine, marten, and the long-tailed weasel. A gray wolf pack has been observed at the eastern end of the range, in Moffat County, Colorado. Raptors include bald and golden eagles, turkey vultures, various hawks and harriers, and owls including

767-1013: 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 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

826-644: 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 is related to the Grand Canyon in both appearance and geologic history. The nickname "Red Rock Country" suggests

885-726: 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

944-556: 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 is drained by the Colorado River and its main tributaries :

1003-456: 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

1062-728: 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

1121-728: 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 Uinta Mountains The Uinta Mountains ( / j uː ˈ ɪ n t ə / yoo- IN -tə ) are an east-west trending mountain range in northeastern Utah extending

1180-547: 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,

1239-605: 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

SECTION 20

#1732787811873

1298-795: 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

1357-540: 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

1416-466: 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

1475-489: 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

1534-528: 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 the section's component plateaus. This fault pattern is caused by the tensional forces pulling apart the adjacent Basin and Range Province to

1593-538: 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

1652-529: The Green was the "master stream" where it and the Colorado River came together.) The Bear and Weber rivers, the two largest tributaries of Great Salt Lake , are born on the west slope of the range. The Provo River , the largest tributary to Utah Lake , begins on the southern side of the range and flows west to Utah Lake, which itself drains via the Jordan River into Great Salt Lake. Large portions of

1711-501: 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

1770-770: The Moosehorn Lake, Mount Watson, Hades Peak, and Red Shale formations. The flanks of the east-west trending Uinta Mountains contain a sequence of Paleozoic and Mesozoic strata ranging from the Cambrian Lodore Formation to the Cretaceous Mancos Shale , all of which have been tilted during the uplift of the mountain range. The uplift of the range dates to the Laramide orogeny , about 70 to 50 million years ago, when compressive forces produced high-angle reverse faults on both

1829-734: 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 the Ancients , Chaco Culture National Historical Park and the Colorado National Monument . This province is bounded by the Rocky Mountains in Colorado and by

North Central Arizona - Misplaced Pages Continue

1888-749: 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 ,

1947-607: 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

2006-619: 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 the Tushar Mountain Plateau as part of

2065-690: 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 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

2124-497: The great horned owl, great grey owl, and barn owls. Other notable large birds include the sage grouse and white-tailed ptarmigan. The Uintas are home to Camp Steiner , the highest Boy Scout camp in the U.S., at 10,400 feet (3,200 m). The camp is near mile marker 33 of the Mirror Lake Highway. The Uinta Highline Trail traverses the entire range and is a popular backpacking trail. Dinosaur National Monument

2183-631: The high peaks are outcrops of the Uinta Mountain Group. Many of the peaks are ringed with bands of cliffs, rising to form broad or flat tops. The mountains are bounded to the north and south by reverse faults that meet below the range, on the north by the North Flank fault and on the south by the Uinta Basin boundary fault. The Uinta Mountain Group, from oldest to youngest, includes Uinta Mountain undivided quartz arenite , overlain by

2242-591: The highest point being Kings Peak , also the highest point in Utah. The Mirror Lake Highway crosses the western half of the Uintas on its way to Wyoming. Utah State Route 44 crosses the east end of the Uintas between Vernal and Manila . The name "Uinta" derives from the Ute word Yoov-we-teuh , meaning "pine forest" or "pine tree". The Uinta Mountains are Laramide uplifted metasedimentary rocks deposited in an intracratonic basin in southwest Laurentia during

2301-468: 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

2360-739: 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

2419-411: The last ice age , and most of the large stream valleys on both the north and south sides of the range held long valley glaciers . However, despite reaching to over 13,500 feet (4,110 m) in elevation, the climate today is sufficiently dry that no glaciers survived even before the rapid current glacial retreat began in the middle nineteenth century. The Uintas are the most poleward mountain range in

North Central Arizona - Misplaced Pages Continue

2478-488: 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

2537-506: 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

2596-587: The mountain range receive over 40 inches (100 cm) of precipitation annually. The high Uintas are snowcapped most of the year except for late July through early September. The Uinta Mountains have more than 400 miles (640 km) of streams and 1,000 lakes and ponds. The Uinta Mountains are part of the Wasatch and Uinta montane forests ecoregion . Nearly the entire range lies within Uinta-Wasatch-Cache National Forest (on

2655-462: 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

2714-477: The north and south sides of the present mountain range. The east-west orientation of the Uintas is anomalous compared to most of the ranges of the Rocky Mountains ; it may relate to changing stress patterns and rotation of the Colorado Plateau . The Green River used to flow into the Mississippi River to the Gulf of Mexico , but changed to the Colorado River by going through the Uintas in ways not fully understood. The high Uintas were extensively glaciated during

2773-399: The north and west) and Ashley National Forest (on the south and east). The range's highest peaks are protected as part of the High Uintas Wilderness . The forests contain many species of trees, including lodgepole pine , subalpine fir , Engelmann spruce , Douglas-fir , and quaking aspen . There are also many species of grasses, shrubs, and forbs growing in the Uinta Mountains. Fauna

2832-530: 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

2891-410: 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

2950-594: 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 ;

3009-404: 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

SECTION 50

#1732787811873

3068-453: 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

3127-462: 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

3186-401: 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;

3245-408: The time of the breakup of the supercontinent Rodinia . The marine and fluvial metasedimentary rocks in the core of the Uinta Mountains are of Neoproterozoic age (between about 700 million and 760 million years old) and consist primarily of quartzite , slate , and shale . These rocks comprise the Uinta Mountain Group , and reach thicknesses of 13,000 to 24,000 feet (4.0 to 7.3 km). Most of

3304-423: 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

3363-430: 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 the Wasatch Line and its various faults form the province's western edge. Faults that run parallel to

3422-404: The world to reach over 13,000 feet (4,000 m) without modern glaciers, and are in fact the highest mountain range in the contiguous United States with no modern glaciers. Permafrost occurs at elevations above 10,000 feet (3,000 m) and at times forms large rock glaciers . Between the summits and ridgelines are wide, level basins with around 500 small lakes. One of the most popular lakes

3481-462: 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

#872127