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83-635: This rock formation is particularly prominent in the Grand Canyon , where it is visible as a prominent white cliff-forming layer. The thickness of the formation varies due to regional structural features; in the Grand Canyon area it is only 65 feet (20 m) thick in the west, thickens to over 600 feet (180 m) in the middle and then thins to 57 feet (17 m) in the east. Either the Kaibab Limestone or Toroweap Formation overlies

166-544: A dry-summer subalpine climate ( Köppen Dsc ). Most of the plateau is within the 6b USDA Hardiness Zone (-5°F to 0°F), with the highest elevations in the 6a zone (-10°F to -5°F). There is no weather station at the summit, but this climate table contains interpolated data for an area around the summit. Dry Park is a Remote Automated Weather Station located 6 miles northwest of the Kaibab Plateau High Point, at an elevation of 8706 ft (2654 m). At

249-476: A sipapu . In September 1540, under orders from the conquistador Francisco Vázquez de Coronado to search for the fabled Seven Cities of Cibola , Captain García López de Cárdenas , along with Hopi guides and a small group of Spanish soldiers, traveled to the south rim of the Grand Canyon between Desert View and Moran Point. Pablo de Melgrossa, Juan Galeras, and a third soldier descended some one third of

332-441: A Notice of Intent to suspend approvals for new uranium mining in the area. In 2012, Salazar established a 20-year moratorium (known as the "Northern Arizona Withdrawal") withdrawing 1 million acres (4,000 km ) from the permitting process for uranium and hardrock mining, stating "People from all over the country and around the world come to visit the Grand Canyon. Numerous American Indian tribes regard this magnificent icon as

415-439: A band of Native Americans to Christianity. He described the canyon as "profound". James Ohio Pattie, along with a group of American trappers and mountain men, may have been the next European to reach the canyon, in 1826. Jacob Hamblin , a Mormon missionary, was sent by Brigham Young in the 1850s to locate suitable river crossing sites in the canyon. Building good relations with local Hualapai and white settlers, he reached

498-715: A dense barrier. Groundwater from the C-acquifer can flow laterally, appearing as seeps along the canyon walls at the base of the Coconino Sandstone but can also descend vertically through fault zones to recharge the underlying confined R-aquifer. The R-aquifer, also known as the Red Wall Muav aquifer, is a karst aquifer. It involves an area of substantial fracturing through the Redwall Limestone, Temple Butte Formation and Cambrian Muav Limestone of

581-440: A great increase in numbers during the early decades of the 20th century. One estimate put the population as high as 100,000 deer inhabiting the range in 1924. Again, there was no systematic survey to support this estimate, which may have been exaggerated to twice the actual number. Shortly after that time, however, the deer population did begin to decline from over-browsing . By the mid-1920s, many deer were starving to death. After

664-542: A group of Spanish soldiers, explored southern Utah and traveled along the north rim of the canyon in Glen and Marble Canyons in search of a route from Santa Fe to California in 1776. They eventually found a crossing, formerly known as the "Crossing of the Fathers", that today lies under Lake Powell . Also in 1776, Fray Francisco Garces, a Franciscan missionary, spent a week near Havasupai unsuccessfully attempting to convert

747-402: A heated legal dispute between the federal government and the state of Arizona, hunting was once more permitted, to reduce the deer's numbers. Hunters were able to kill only a small fraction of the starving deer. The range itself was damaged, and its carrying capacity was greatly reduced. Once ecologists began to study the area and reflect on the changes that had occurred there, they began to use

830-566: A result the team eventually had to subsist on starvation rations. Passing through (or portaging around) a series of dangerous rapids, the group passed down the Green River , reaching its confluence with the Colorado River, near present-day Moab, Utah , on July 17. Continuing on down the Colorado River, the party encountered more rapids and falls. On August 28, 1869, faced with what some felt to be impassable rapids, three men left

913-513: A sacred place and millions of people in the Colorado River Basin depend on the river for drinking water, irrigation, industrial and environmental use." However, Salazar's 20-year moratorium on new mines still allows mines with previous authorization to operate. Multiple challenges have been brought into court both against the moratorium and against the operation of uranium mines in the area. The federal government's 2012 moratorium

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996-720: A similar source to the Havasu Spring upwelling from the Redwall-Muav aquifer. Sites with younger estimated mean ages tend to be associated with the unconfined Coconino aquifer. They may recharge quickly as a result of snowmelt, run-off and local precipitation. It is likely that the deeper confined R-aquifer relies primarily on snowmelt from the San Francisco Peaks to recharge. Other research has tried to relate groundwater flow paths to possible levels of risk for contamination and identify vulnerability regions for

1079-515: A substantial departure from prior widely supported scientific consensus. In a 2008 study, Victor Polyak examined caves near the Grand Canyon and placed their origins about 17   million years ago. The study, which was published in the journal Science in 2008, used uranium-lead dating to analyze calcite deposits found on the walls of nine caves throughout the canyon. In another 2008 study, Rebecca Flowers reported on apatite (U-Th)/He thermochronometry results suggesting that parts of

1162-589: A time the only record concerning this rather mythical locality, was rather magnified than detracted from by the accounts of one or two trappers, who professed to have seen the cañon". According to the San Francisco Herald , in a series of articles run in 1853, Captain Joseph R. Walker in January 1851 with his nephew James T. Walker and six men, traveled up the Colorado River to a point where it joined

1245-702: A wide area stretching from the San Francisco Peaks eastwards towards the Four Corners. Archaeological and linguistic evidence suggests the Navajo descended from the Athabaskan people near Great Slave Lake , Canada, who migrated after the 11th   century. In the mythology of some Third Mesa Hopi communities, the Grand Canyon was the location humankind arose out of the Third World from

1328-690: Is a plateau almost entirely in Coconino County, Arizona (but extending slightly north into Kane County , Utah ) in the Southwestern United States . The high plain is also known as the Buckskin Mountain , Buckskin Plateau , and Kaibab Mountain . The plateau, part of the larger Colorado Plateau , is bordered on the south by the Grand Canyon and reaches an elevation of 9,200 feet (2,800 m). The plateau

1411-470: Is a marble platform caused by a monoclinical fold, which strata dips down 2,000 to 3,000 feet. The climate of the Kaibab Plateau consists of rain and thunderstorms in late summer during the summer monsoon season, snow, heavy at times, in winter, and drier weather in early summer. There was an average annual precipitation of 26.57 inches (67.5 cm) for the period 1925 to 1936. During winter, snow

1494-775: Is a steep-sided canyon carved by the Colorado River in Arizona , United States. The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,093 feet or 1,857 meters). The canyon and adjacent rim are contained within Grand Canyon National Park , the Kaibab National Forest , Grand Canyon–Parashant National Monument , the Hualapai Indian Reservation ,

1577-567: Is bounded on the south by the Grand Canyon of the Colorado River, the elevation in this southern area of the plateau varies from 8,800 feet (2,700 m) to slightly less than 6,000 feet (1,800 m). The most extensive platform of the plateau is the Esplanade, which is called "Sand Rocks" by local cowboys. This area was formed as a result from weathering of the Hermit shale, which left a hard layer of Permian sandstone exposed. This red sandstone

1660-574: Is called a confined aquifer, while water below the surface and above an aquitard is called an unconfined aquifer. The different geologic levels of the Grand Canyon have created two major aquifers where groundwater collects. The higher C-aquifer is an unconfined aquifer. It collects groundwater that seeps through the Kaibab and Toroweap Formations into the Coconino Sandstone. Below it, the Permian Hermit Formation and Supai Group provide

1743-453: Is divided between Kaibab National Forest and the "North Rim" portion of Grand Canyon National Park . Tributary canyons of the Colorado River form the plateau's eastern and western boundaries, and tiers of uplifted cliffs define the northern edges of the landform . Winter snowfall is often heavy (sometimes exceeding 17 feet [5.2 m]), and this creates opportunities for backcountry Nordic skiing and snow camping. This broad feature

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1826-472: Is heavily forested with aspen , spruce - fir , ponderosa pine , and pinyon-juniper woodland , and stands in sharp contrast to the arid lowlands encircling it. The cool forests of the plateau are home to the Kaibab squirrel , which is endemic to the region. Other fauna includes deer , turkey , cougar , and bobcat . The Kaibab deer are particularly important because of the changes in their population during

1909-466: Is heavy and often accumulates at a depth of 8–10 feet (2.4–3.0 m). June is the driest month of the year, followed by May and early July. Storms occur several times each week until early September. The highest portions of the plateau are usually touched by snow, and snowstorms usually occur between May and September. The Kaibab Plateau High Point, 9,213 ft (2,808 m), has a dry-summer humid continental climate ( Köppen Dsb ), bordering on

1992-495: Is known for its visually overwhelming size and its intricate and colorful landscape. Geologically, it is significant because of the thick sequence of ancient rocks that are well preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continent. Uplift associated with mountain formation later moved these sediments thousands of feet upward and created

2075-618: Is one of the outstanding features of the plateau. The plateau's western boundary is the Kanab Creek Canyon which high perpendicular walls form a natural barrier to the movement of most animals. The northwestern boundary of the plateau is marked by a fault line north of the Snake Gulch which is approximately sixteen miles to the east of the Kanab Creek. The eastern boundary is marked by the so-called Houserock Valley, which

2158-629: The Boone and Crockett Club helped form the National Parks Association , which in turn lobbied for the Antiquities Act of 1906 which gave Roosevelt the power to create national monuments. Once the act was passed, Roosevelt immediately added adjacent national forest lands and redesignated the preserve a U.S. National Monument on January 11, 1908. Opponents such as land and mining claim holders blocked efforts to reclassify

2241-472: The Crossing of the Fathers , crossed the location that would become Lees Ferry on a raft in 1858 and Pearce Ferry (later operated by, and named for, Harrison Pearce ). He also acted as an advisor to John Wesley Powell , before his second expedition to the Grand Canyon, serving as a diplomat between Powell and the local native tribes to ensure the safety of his party. In 1857, Edward Fitzgerald Beale

2324-701: The EPA ' s Maximum Contaminant Level for drinking water, 30 μg/L. At 86% of sites, uranium concentrations were below the Canadian level for protection of freshwater aquatic life, 15 μg/L. On August 8, 2023, it was announced that U.S. President Joe Biden will designate Baaj Nwaavjo I’tah Kukveni – Ancestral Footprints of the Grand Canyon National Monument, a move aimed at conserving nearly 1 million acres of greater Grand Canyon landscape. Kaibab Plateau The Kaibab Plateau

2407-643: The Havasupai Indian Reservation and the Navajo Nation . The surrounding area is contained within the Baaj Nwaavjo I'tah Kukveni – Ancestral Footprints of the Grand Canyon National Monument . President Theodore Roosevelt was a major proponent of the preservation of the Grand Canyon area and visited it on numerous occasions to hunt and enjoy the scenery. Nearly two billion years of Earth's geological history have been exposed as

2490-618: The Pecos Classification , suggests their emergence was around 1200  BCE during the Basketmaker II Era . Beginning with the earliest explorations and excavations, researchers have believed that the Ancestral Puebloans are ancestors of the modern Pueblo peoples . In addition to the Ancestral Puebloans, a number of distinct cultures have inhabited the Grand Canyon area. The Cohonina lived to

2573-485: The elevation summary of the Colorado River for present conditions). Weather conditions during the ice ages also increased the amount of water in the Colorado River drainage system. The ancestral Colorado River responded by cutting its channel faster and deeper. The base level and course of the Colorado River (or its ancestral equivalent) changed 5.3   million years ago when the Gulf of California opened and lowered

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2656-578: The formations were deposited in warm shallow seas, near-shore environments (such as beaches), and swamps as the seashore repeatedly advanced and retreated over the edge of a proto-North America. Major exceptions include the Permian Coconino Sandstone , which contains abundant geological evidence of aeolian sand dune deposition. Several parts of the Supai Group also were deposited in non-marine environments. The great depth of

2739-607: The C-aquifer. Much of the water that could potentially recharge the aquifers is likely released as springs rather than reaching the aquifers. Studies of the chemical composition of groundwater at sites across the Grand Canyon region indicate that groundwater contains a fraction of modern water (post-1950), and that many springs have a mix of modern water and older groundwater. Estimated mean ages for South Rim groundwater range from 6 years old (San Francisco Peaks) to nearly 20,000 years old (Bar Four well, Blue Spring). Groundwater age in

2822-429: The Coconino Sandstone. The Coconino Sandstone is typically buff to white in color. It consists primarily of fine well-sorted quartz grains, with minor amounts of potassium feldspar grains deposited by eolian processes (wind-deposited) approximately 275 million years ago. Several structural features such as ripple marks , sand dune deposits, rain patches, slump marks, and fossil tracks are not only well preserved within

2905-646: The Colorado Plateau. The higher elevation has also resulted in greater precipitation in the Colorado River drainage area, but not enough to change the Grand Canyon area from being semi-arid. The uplift of the Colorado Plateau is uneven, and the Kaibab Plateau that the Grand Canyon bisects is over one thousand feet (300 m) higher at the North Rim than at the South Rim. Almost all runoff from

2988-491: The Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted . While some aspects about the history of incision of the canyon are debated by geologists, several recent studies support the hypothesis that the Colorado River established its course through the area about 5 to 6 million years ago. Since that time, the Colorado River has driven

3071-477: The Colorado River and the Grand Canyon in the first expedition down the canyon. Powell ordered a shipwright to build four reinforced Whitewall rowboats from Chicago and had them shipped west on the newly completed Continental railroad. He hired nine men, including his brother Walter, and collected provisions for ten months. They set out from Green River, Wyoming , on May 24. On June 7, they lost one of their boats, 1/3 of their food, and other badly-needed supplies: as

3154-648: The Colorado all of the way to the Gulf of California . The Grand Canyon became an official national monument in 1908 and a national park in 1919. U.S. President Theodore Roosevelt visited the Grand Canyon in 1903. An avid outdoorsman and staunch conservationist, Roosevelt established the Grand Canyon Game Preserve on November 28, 1906. Livestock grazing was reduced, but predators such as mountain lions, eagles, and wolves were eradicated. Roosevelt along with other members of his conservation group,

3237-590: The Department of Interior started experimenting with “adaptive management” of the Glen Canyon Dam, using a High-Flow Experiment (HFE) water release to shift volumes of sand and monitoring effects such as the dispersal of invasive tamarisk seeds. However, as of 2022, extreme drought has caused water levels in Lake Powell to drop so much that a planned release of water has been delayed, to ensure that

3320-518: The Forest Service had not acted arbitrarily in making its decision. A study examining samples of groundwater from 180 spring sites and 26 wells in the Grand Canyon region has assessed the presence of uranium in groundwater from September 1, 1981, to October 7, 2020. The goal of the study was to establish a baseline assessment of groundwater conditions in the Grand Canyon region. At 95% of sites, maximum observed uranium concentrations were below

3403-423: The Glen Canyon Dam can continue to generate hydropower . Between 2003 and 2011, 2,215 mining claims had been requested that are adjacent to the canyon, including claims for uranium mines. Critics of uranium mining are concerned that uranium will leach into the aquifers feeding the Colorado River and contaminate the water supply for up to 18 million people. In 2009, U.S. Interior Secretary Ken Salazar published

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3486-623: The Grand Canyon Trust sought to block the reopening of the Pinyon Plain Mine (formerly Canyon Uranium Mine). Activity at the mine had ceased in 1992, ten years prior to the moratorium on new development in 2012. Appellants challenged the U.S. Forest Service's consultation process for approving reopening of the mine. As of February 22, 2022, the 9th U.S. Circuit Court of Appeals rejected the arguments in No. 20-16401, concluding that

3569-500: The Grand Canyon and especially the height of its strata (most of which formed below sea level) can be attributed to 5,000–10,000 feet (1,500–3,000 m) of uplift of the Colorado Plateau, starting about 65   million years ago (during the Laramide orogeny ). This uplift has steepened the stream gradient of the Colorado River and its tributaries, which in turn has increased their speed and thus their ability to cut through rock (see

3652-584: The Grand Canyon and tributary canyons. Springs discharge to the Grand Canyon in areas of lower Paleozoic carbonates, and are associated with geologic faults and fractures. Fractures are believed to provide dominant pathways both for vertical circulation in the Paleozoic section, and for lateral collection and transport of water to springs deep in the canyons. The largest springs discharge from the R-aquifer. A smaller number of springs discharge at lower rates from

3735-425: The Grand Canyon had reached a depth near to the modern depth around 20   million years ago. In a subsequent study published in the journal Science in 2012, she suggested that the western part of the Grand Canyon could be as old as 70   million years. The emerging scientific consensus is that the canyon is made up of multiple segments which formed at different times and eventually connected to become

3818-430: The Kaibab deer as a simple lesson about how the removal of the deer's natural predators , which had been done in the interest of preserving the deer population, had allowed the deer to over-reproduce, and quickly overwhelm the plateau's resources. Some ecologists suggested that the situation highlighted the importance of keeping a population in balance with its environment's carrying capacity. The more meaningful lesson of

3901-499: The Kaibab suggests that human efforts to protect wildlife and preserve wild areas must be balanced with ecological complexity and social priorities that are difficult to predict. Changes take place, sometimes rapidly, but their effects linger for decades. Today, the Arizona Game Commission manages the area, controlling the numbers of deer as well as predators, and issues hunting permits to keep the deer in balance with

3984-403: The North Rim (which also gets more rain and snow) flows toward the Grand Canyon, while much of the runoff on the plateau behind the South Rim flows away from the canyon (following the general tilt). The result is deeper and longer tributary washes and canyons on the north side and shorter and steeper side canyons on the south side. Temperatures on the North Rim are generally lower than those on

4067-553: The South Rim because of the greater elevation (averaging 8,000 feet or 2,400 meters above sea level). Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon ( State Route 67 ) is limited during the winter season due to road closures. The Grand Canyon is part of the Colorado River basin, which has developed over the past 70   million years. For more than 150 years, scientists have gathered data, proposed new ideas, and debated sometimes contentious theories about

4150-578: The South Rim groundwater system also correlates to longitude, with age increasing from east to west from Red Canyon to Boucher springs. Surprisingly, the Canyon Mine Observation well is more similar to Redwall-Muav aquifer wells (R-aquifer) than to the Coconino C-aquifer. This suggests the possibility of a hydrologic connection or similar recharge sources for that hydrologic position. Old groundwater from Havasupai well may have

4233-536: The Tonto Group. Five individual systems flow through the R-aquifer and compose the regional groundwater-flow system which drains into the Grand Canyon: Kaibab, Uinkaret-Kanab, Marble-Shinumo, Cataract, and Blue Spring. The flow of groundwater in the Grand Canyon region is influenced in multiple ways by geologic faults and folds . Discharge from the R-aquifer appears as springs and seeps in both

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4316-547: The United States. They were the first people known to live in the Grand Canyon area. The cultural group has often been referred to in archaeology as the Anasazi, although the term is not preferred by the modern Puebloan peoples . The word "Anasazi" is Navajo for "enemy ancestors" or "alien ancestors". Archaeologists still debate when this distinct culture emerged. The current consensus, based on terminology defined by

4399-500: The Virgin River and continued east into Arizona, traveling along the Grand Canyon and making short exploratory side trips along the way. Walker is reported to have said he wanted to visit the "Moqui" (Hopi) Indians. who he had met briefly before and found exceptionally interesting. In 1858, John Strong Newberry became probably the first geologist to visit the Grand Canyon. In 1869, Major John Wesley Powell set out to explore

4482-432: The area was probably due to a period of severe overbrowsing by a large population of deer. This, they write, is consistent with the original assessment of the rapid rise in deer population as a result of persistent predator control. Their contribution of original research is a refreshing addition to the ongoing discussion of predator-prey interactions on the Kaibab. [Binkley, Dan, et al., 2006. "Was Aldo Leopold right about

4565-406: The beginning of the 20th century, the Kaibab Plateau was witness to an interesting experiment in what some might call population engineering. The plateau's pre-1905 population of mule deer was estimated to be around 4,000. This number was never confirmed by any kind of count or survey, and has become an accepted number mainly because no other estimate is available. The average carrying capacity of

4648-474: The deer Caughley's opinion led to confusion by teachers and scientists over what to include and teach in ecology and biology classes, therefore this story stopped being used as an example of prey and predator population dynamics. This is important to the development of scientific studies because it shows that events—like the Kaibab deer controversy—do not have a definitive start and beginning but include other opinions and approaches which teachers use to showcase

4731-409: The down-cutting of the tributaries and retreat of the cliffs, simultaneously deepening and widening the canyon. For thousands of years, the area has been continuously inhabited by Native Americans, who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon a holy site, and made pilgrimages to it. The first European known to have viewed the Grand Canyon

4814-459: The early 1900s. This particular fluctuation is a great example of population engineering and the effects humans can have on nature. The Kaibab Plateau consists of approximately 1,152 square miles (2,980 km ) which are above 6,000 feet (1,800 m). The highest point has an elevation of 9,200 feet (2,800 m), a topographic prominence of 3,580 feet (1,090 m), and a topographic isolation of 70.44 miles (113.36 km). The plateau

4897-426: The expedition on foot in an attempt to reach a settlement 75 miles (121 km) away. Ironically, the remaining members went safely through the rapids on August 29, 1869, while Seneca Howland, Oramel Howland, and William H. Dunn were murdered. The area through which the three men traveled was marked by tensions between farming and hunting Shivwits and incoming Mormon settlers. Which group was responsible for killing

4980-430: The formation, but also contribute evidence of its eolian origin. Lechatelierite (silica glass), as well as coesite and stishovite (high pressure forms of SiO 2 ) were formed during the impact of a meteorite into the Coconino Sandstone at Barringer Crater in Arizona . Sequence of layers: Coconino Sandstone on Hermit Shale on sloping redbeds of Supai Group . Grand Canyon The Grand Canyon

5063-499: The geologic origins of the Grand Canyon and the Colorado River. Formation of the Grand Canyon and the Colorado River may involve a complex history in which multiple factors and geologic processes have interacted over time and in different locations. In the most recent round of "old river" vs. "young river" controversy, researchers have challenged estimates that had placed the age of the canyon at 5–6   million years. The research has aroused considerable controversy because it suggests

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5146-508: The land was unknown, in part because this concept was not widely used by naturalists at the time. Years later, Aldo Leopold estimated that the capacity had been about 30,000 deer. The idea in 1906 was simply to protect and expand the herd, so on November 28, President Theodore Roosevelt created the Grand Canyon National Game Preserve. Overgrazing by herds of sheep, cattle, and horses had taken place on

5229-652: The lower end of Black Canyon on March 8, 1858, then continued on by rowboat past the mouth of the Virgin River after the Explorer struck a rock. Ives led his party east into the canyon – they may have been the first Europeans to travel the Diamond Creek drainage. In his "Report Upon the Colorado River of the West" to the Senate in 1861 Ives states that "The marvellous story of Cardinas , that had formed for so long

5312-557: The monument as a U.S. National Park for 11 years. Grand Canyon National Park was finally established as the 17th U.S. National Park by an Act of Congress signed into law by President Woodrow Wilson on February 26, 1919. The federal government administrators who manage park resources face many challenges. These include issues related to the recent reintroduction into the wild of the highly endangered California condor , air tour overflight noise levels, water rights and management disputes, and forest fire management. The canyon's ecosystem

5395-465: The party admitted that he never before saw anything to match or equal this astonishing natural curiosity." Also in 1857, the U.S. War Department asked Lieutenant Joseph Ives to lead an expedition to assess the feasibility of an up-river navigation from the Gulf of California. On December 31, 1857, Ives embarked from the mouth of the Colorado in the stern wheeler steamboat Explorer . His party reached

5478-710: The plateau since the 1880s. During that time, many predators were also killed by ranchers and bounty hunters. By the time Roosevelt established the game preserve, ranchers had moved most domestic livestock elsewhere. The primary change brought by the creation of the game preserve was to ban deer hunting. Government efforts, led by the United States Forest Service , began to protect the deer's numbers by killing off their natural predators once again; to this end, between 1907 and 1939, 816 mountain lions , 20 wolves , 7388 coyotes and over 500 bobcats were reportedly killed. The deer population experienced

5561-416: The range. Although the story of the Kaibab deer rose to fame in the 1920s due to their sudden increase and decrease in population, the story can also be used to demonstrate the way in which scientific studies and ideas about history can help educate current students. The first interpretation of the deer story as demonstrated in textbooks was that predator control had destroyed the deer's population growth. It

5644-425: The richness of controversy. In the summers of 2002 and 2003, forest ecologist Dan Binkley and associates undertook a careful analysis of the age structure of aspen stands on the Kaibab. Their work shows that few aspen sprouted successfully on the plateau in the 1920s. They ruled out browsing by domestic livestock or exceptionally dry conditions as causes of that change and concluded that the age structure of aspen in

5727-423: The river's base level (its lowest point). This increased the rate of erosion and cut nearly all of the Grand Canyon's current depth by 1.2   million years ago. The terraced walls of the canyon were created by differential erosion . Between 100,000 and 3   million years ago, volcanic activity deposited ash and lava over the area, which at times completely obstructed the river. These volcanic rocks are

5810-594: The second Director of the US Geological Survey (1881–1894). He was the first to use the term "Grand Canyon", in 1871; previously it had been called the "Big Canyon". In 1889, Frank M. Brown wanted to build a railroad along the Colorado River to carry coal. He, his chief engineer Robert Brewster Stanton , and 14 others started to explore the Grand Canyon in poorly designed cedar wood boats, with no life preservers. Brown drowned in an accident near Marble Canyon : Stanton made new boats and proceeded to explore

5893-549: The three men has been hotly debated. Powell himself visited the area the following year, and was told (through a Mormon interpreter) that the Shivwits had mistakenly killed the men, believing them to be prospectors who had murdered an Indian woman. He chose to smoke a peace pipe with them. Powell went on to become the first Director of the U.S. Bureau of Ethnology of the Smithsonian Institution (1879–1902) and

5976-468: The time of the arrival of Europeans in the 16th   century, newer cultures had evolved. The Hualapai inhabit a 100-mile (160 km) stretch along the pine-clad southern side of the Grand Canyon. The Havasupai have been living in the area near Cataract Canyon since the beginning of the 13th   century, occupying an area the size of Delaware . The Southern Paiutes live in what is now southern Utah and northern Arizona. The Navajo , or Diné, live in

6059-683: The two-billion-year-old Vishnu Schist at the bottom of the Inner Gorge to the 270-million-year-old Kaibab Limestone on the Rim. Within that there is a gap, the Great Unconformity , between 1.75   billion and 1.25   billion years ago for which no deposits are present. Then, between 1.25   billion and 730   million years ago, intermittent sediments began to form the Grand Canyon Supergroup . Many of

6142-414: The underlying aquifers. Almost half of the Kaibab plateau's surface was associated with high to very high vulnerability of the unconfined Coconino aquifer (C-aquifer), while about a fifth of the Kaibab Plateau was estimated to be an area of high vulnerability for the Redwall-Muav aquifer (R-aquifer). The Ancestral Puebloans were a Native American culture centered on the present-day Four Corners area of

6225-431: The waterway now traversed by the Colorado River. Of the three central segments, the "Hurricane" was formed 50–70   million years ago, and the "Eastern Grand Canyon" was cut 15–25   million years ago. In contrast, the "Marble Canyon" and "Westernmost Grand Canyon" segments at the ends of the canyon were carved in the last five to six million years. The major geologic exposures in the Grand Canyon range in age from

6308-585: The way into the canyon until they were forced to return because of lack of water. In their report, they noted that some of the rocks in the canyon were "bigger than the great tower of Seville, Giralda ". It is speculated that their Hopi guides likely knew routes to the canyon floor, but may have been reluctant to lead the Spanish to the river. No Europeans visited the canyon again for more than two hundred years. Fathers Francisco Atanasio Domínguez and Silvestre Vélez de Escalante were two Spanish priests who, with

6391-612: The west of the Grand Canyon, between 500 and 1200  CE . The Cohonina were ancestors of the Yuman , Havasupai , and Hualapai peoples who inhabit the area today. The Sinagua were a cultural group occupying an area to the southeast of the Grand Canyon, between the Little Colorado River and the Salt River , between approximately 500 and 1425 CE . The Sinagua may have been ancestors of several Hopi clans. By

6474-591: The youngest in the canyon. Groundwater flow in the Grand Canyon region is an active area of study. Groundwater forms when rain soaks down into the earth and reaches the water table . The composition of the earth in a given area determines its permeability , the ease with which water flows through it. Sand is more permeable than clay. Less permeable rock layers composed of clay can block the passage of water and are known as aquitards . More permeable areas of rock that hold and transport groundwater underground are known as aquifers . An area of water bounded by two aquitards

6557-457: Was García López de Cárdenas from Spain, who arrived in 1540. The Grand Canyon is a river valley in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, and it is also one of the six distinct physiographic sections of the Colorado Plateau province. Even though it is not the deepest canyon in the world ( Kali Gandaki Gorge in Nepal is much deeper ), the Grand Canyon

6640-476: Was permanently changed after the construction of the Glen Canyon Dam in 1963. Average flood levels dropped from 85,000 to 8,000 cubic ft/sec. In the absence of natural flooding, sandbars and beaches eroded and invasive species began to displace native species. Federal officials started releasing floods in the Grand Canyon in hopes of restoring its ecosystem beginning with 1996, 2004, and 2008. In 2018,

6723-482: Was superintendent of an expedition to survey a wagon road along the 35th parallel from Fort Defiance, Arizona to the Colorado River. He led a small party of men in search of water on the Coconino Plateau near the canyon's south rim. On September 19, near present-day National Canyon, they came upon what May Humphreys Stacey described in his journal as "a wonderful canyon; four thousand feet deep. Everybody in

6806-524: Was thought that initially the high number of deer predators were obtruding the growth of the deer's population, therefore rules were put in place in order to minimize the predator population and allow the deer to increase their population size. However, as scientific studies continued, ecologist Graeme Caughley suggested that predator control alone could not have caused the Kaibab irruption, but rather factors like climate, grazing by other animals, and preservation policies actually had more significant impacts on

6889-592: Was upheld by the U.S. District Court for Arizona in 2014, but appealed in November 2014 as National Mining Association v. Jewell (No. 14-17350). The 9th Circuit Court of Appeals again upheld the moratorium in 2017, stating that the Secretary of the Interior held valid withdrawal authority. Havasupai Tribe v. Provencio was also argued at multiple court levels based on multiple grounds. The Havasupai people and

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