问题描述：
英语作业
谁给介绍下.
要做PPT的 谁有英文版的那就更谢谢了
问题解答：
http://www.nps.gov/grca/index.htm
The Grand Canyon is more than a great chasm carved over millennia through the rocks of the Colorado Plateau. It is more than an awe-inspiring view. It is more than a pleasuring ground for those that explore the roads, hike the trails, or float the currents of the turbulent Colorado River.
This canyon is a gift that transcends what we experience. Its beauty and size humbles us. Its timelessness provokes a comparison to our short existence. In its vast spaces we may find solace from our hectic lives.
The Grand Canyon we visit today is a gift from past generations. Take time to enjoy this gift. Sit and watch the changing play of light and shadows. Wander along a trail and feel the sunshine and wind on your face. Attend a ranger program. Follow the antics of ravens soaring above the rim. Listen for the roar of the rapids far below. Savor a sunrise or sunset.
As the shadows lengthen across the spires and buttes, time passing into the depths of the canyon, understand what this great chasm passes to us - a sense of humility born in the interconnections of all that is and a willingness to care for this land. We have the responsibility to ensure that future generations have the opportunity to form their own connections with Grand Canyon National Park.
The Grand Canyon is a steep-sided gorge carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, one of the first national parks in the United States. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, and visited it on numerous occasions to hunt and enjoy the scenery.
View from Grandview Point.
A map of the Grand Canyon and surrounding areas, circa 1908.Longstanding scientific consensus has been that the canyon was created by the Colorado River over a six million year period. The canyon is 277 miles (446 km) long, ranges in width from 4 to 18 miles (6.4 to 29 km) and attains a depth of over a mile (1.83 km) (6000 feet).[1] Nearly two billion years of the Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted. The "canyon began in the west, followed by another that formed in the east. Eventually, the two broke through and met as a single majestic rent in the earth some six million years ago. [...] The merger apparently occurred where the river today bends to the west, in the area known as the Kaibab Arch."[2]
Before European immigration, the area was inhabited by Native Americans who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon ("Ongtupqa" in Hopi language) a holy site and made pilgrimages to it.[3] The first European known to have viewed the Grand Canyon was García López de Cárdenas from Spain, who arrived in 1540.[4]
The Grand Canyon is a massive rift in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, and is also one of the six distinct physiographic sections of the Colorado Plateau province. The Grand Canyon is unmatched throughout the world for the vistas it offers to visitors on the rim. It is not the deepest canyon in the world—Yarlung Zangbo Grand Canyon (5,382m or 17,657 ft (1994 old data); 6009m (1998); single side 7057m deep; average depth 2268m; average depth of 250 km kernel zones 2673m) in Tibet, China is far deeper, nor the widest (this is Capertee Valley in Australia - which is about 1 km wider and longer than Grand Canyon), not to mention the largest — but the Grand Canyon is known for its overwhelming size and its intricate and colorful landscape. Geologically it is significant because of the thick sequence of ancient rocks that are beautifully preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continent.
Temples, Castles, and Shrines.Uplift associated with mountain building events later moved these sediments thousands of feet upward and created 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 north-south trending Kaibab Plateau that Grand Canyon bisects is over a thousand feet higher at the North Rim (about 1,000 ft/300 m) than at the South Rim. The fact that the Colorado River flows in a curve around the higher North Rim part of the Kaibab Plateau and closer to the South Rim part of the plateau is also explained by this asymmetry. Ivo Lucchitta of the U.S. Geological Survey first suggested that, as the Colorado River developed before significant erosion of the region, it naturally found its way across or around the Kaibab Uplift by following a "racetrack" path to the south of the highest part of the plateau. Almost all runoff from 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 the South Rim because of the greater elevation (averaging 8,000 ft/2,438 m above sea level).[5] 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. Views from the North Rim tend to give a better impression of the expanse of the canyon than those from the South Rim.
Grand Canyon National Park is one of the world’s premier natural attractions, attracting about five million visitors per year. Overall, 83% were from the United States: California (12.2%), Arizona (8.9%), Texas (4.8%), Florida (3.4%) and New York (3.2%) represented the top domestic visitors. Seventeen percent of visitors were from outside the United States; the most prominently represented nations were the United Kingdom (3.8%), Canada (3.5%), Japan (2.1%), Germany (1.9%) and The Netherlands (1.2%).[30]
[edit] Activities
Further information: Grand Canyon travel guide from Wikitravel
A view of Grand Canyon Skywalk from Outside LedgeAside from casual sightseeing from the South Rim (averaging 7000 feet (2100 m) above sea level), whitewater rafting, hiking and running are especially popular. The floor of the valley is accessible by foot, muleback, or by boat or raft from upriver. Hiking down to the river and back up to the rim in one day is discouraged by park officials because of the distance, steep and rocky trails, change in elevation, and danger of heat exhaustion from the much higher temperatures at the bottom. Rescues are required annually of unsuccessful rim-to-river-to-rim travelers. Nevertheless, hundreds of fit and experienced hikers complete the trip every year.
Aerial view of the less-visited lower Grand Canyon, down river from (west of) Toroweap Overlook
Grand Canyon as seen from a commercial airplaneCamping on the North and South Rims is generally restricted to established campgrounds and reservations are highly recommended, especially at the busier South Rim. There is at large camping available along many parts of the North Rim managed by Kaibab National Forest. Keep in mind North Rim campsites are only open seasonally due to road closures from weather and winter snowpack. All overnight camping below the rim requires a backcountry permit from the Backcountry Country Office (BCO). Each year Grand Canyon National Park receives approximately 30,000 requests for backcountry permits. The park issues 13,000 permits, and close to 40,000 people camp overnight.[31] The earliest a permit application is accepted is the first of the month, four months before the proposed start month. Applying as soon as allowed will improve your chances of obtaining an overnight backcountry use permit for the dates of your choice. If you are unable to secure a permit from the Grand Canyon Backcountry Office, or you are not comfortable hiking the Canyon on your own you can go with a professional guide.
The Coconino Canyon Train is another option for those seeking to take in a more leisurely view of the canyon. It is a 90-minute ride that originates in Grand Canyon National Park at the old Grand Canyon Depot and travels 24 miles through the canyon landscapes. The train is made up of 1923 Pullman cars and runs on tracks built in the 1800s. [32]
Tourists wishing for a more vertical perspective can board helicopters and small airplanes in Las Vegas, Phoenix and Grand Canyon National Park Airport (seven miles from the South Rim) for canyon flyovers. Scenic flights are no longer allowed to fly within 1500' of the rim within the national park because of a late 90s crash. The last aerial video footage from below the rim was filmed in 1984. However, some helicopter flights land on the Havasupai and Hualapai Indian Reservations within Grand Canyon (outside of the park boundaries). Recently, the Hualapai Tribe opened the glass-bottomed Grand Canyon Skywalk on their property, Grand Canyon West. The Skywalk has seen mixed reviews since the site is only accessible by driving down a 14-mile (23 km) dirt road, costs a minimum of $85 in total for reservation fees, a tour package and admission to the Skywalk itself and the fact that cameras are not permitted on the Skywalk at any time. The Skywalk is some 240 miles west of Grand Canyon Village at the South Rim. Some people mistake the area of Hermit's Rest as the location of the Skywalk.[citation needed]
[edit] Viewing the canyon
Home video: a flight over the Grand Canyon - with sound (approx. 6 Minutes)Lipan Point is a promontory located on the South Rim. This point is located to the east of the Grand Canyon Village along the Desert View Drive. There is a parking lot for visitors who care to drive along with the Canyon's bus service that routinely stops at the point. The trailhead to the Tanner Trail is located just before the parking lot. The view from Lipan Point shows a wide array of rock strata and the Unkar Creek area in the inner canyon.
The canyon can be seen from the Toroweap (or Tuweep) Overlook situated 3000 vertical feet above the Colorado River, about 50 miles downriver from the South Rim and 70 upriver from the Grand Canyon Skywalk. This region — “One of the most remote in the United States” according to the National Park Service — is reached only by one of three lengthy dirt tracks, that start from St. George, Utah, Colorado City or near Pipe Spring National Monument (both in Arizona). These roads traverse wild, uninhabited land for 97, 62 and 64 miles respectively. The Park Service manages the area for its primitive values and, therefore, improvements and services are minimal.
现成的ppt：
http://www.sln.org.uk/geography/Documents/geocreativity/The%20Grand%20Canyon.ppt
http://gsa.confex.com/gsa/responses/2006RM/177.ppt
http://datamonster.sbs.arizona.edu/IGERT/outreach/middle/grandcanyon.ppt
https://www.e-education.psu.edu/files/geosc10/downloads/u10/u10_vtrip2_grandcanyon.ppt
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