I. Introduction
The Colorado Grand Canyon is a world-famous natural wonder, and the Colorado River flows through it. It is one of the natural heritages that UNESCO has chosen to protect. The Grand Canyon, located on the Kaibabu Plateau in northwest Arizona, is one of the most magnificent scenery on earth.
The Colorado River cuts 19 major canyons on the Colorado Plateau, with a total area of 2,724.7 square kilometers, of which the deepest, widest and longest is the Grand Canyon. It is 446 kilometers long and is one of the longest canyons in the world. The top of the canyon is 6-28km wide and the deepest part is1800m. The width of the valley bottom water surface is less than 1000 meters. In summer, the ice and snow melt, and the water depth increases to 18m. Most of the rocks are red.
Second, the geographical environment
1, location
The Grand Canyon is located on the Colorado Plateau in Arizona, USA, and the Colorado River flows through it. ***446 kilometers, the deepest part is about 1.6 kilometers, about 500 stories high, and the widest part is 13 kilometers. The history of the earth's development is engraved on its gorge wall-about one-third of the history of crustal changes is deeply recorded on the stone wall, and the rocks at the bottom of the valley have undergone about two billion years of changes, which is half the age of the earth.
2. Terrain
The Grand Canyon of the United States is known as a "living geological history textbook" because of its representative geological fossils. Colorado Plateau is a typical "Table Mountain", also known as "Table Mountain", that is, a mountain with a flat top and steep sides. This terrain is formed by erosion (undercut and spalling).
During the period of erosion, the hard rock strata on the plateau constitute the protective cap of the inter-valley area, and the erosion in the valley is active. The result is a platform mountain or fortress mountain.
3. Hydrology
The Grand Canyon is a masterpiece of the Colorado River. The river rises in the Rocky Mountains in Colorado, flows through Utah and Arizona, and enters the sea from California Bay in California. The total length is 2320 kilometers. Colorado means "Red River" in Spanish. This is because the river carries a lot of sediment, and the river is often red, so it is named.
The long-term scouring of the Colorado River, which runs day and night, sometimes cuts mountains and splits roads, and sometimes makes way for backflow. Black Canyon, Canyon Land, Glen Canyon, Bruce Canyon and other 19 canyons are carved in the upper reaches of the mainstream and tributaries. Finally, when it flows through the rocky Kaibabu Plateau in Arizona, it is even more amazing, forming the wonders of this grand canyon and becoming the "king of canyons" of all the canyons in this water system.
4. Geology
Due to the different stratum structure, the Grand Canyon is loose and dense, and the rivers are on the rampage, sometimes causing large-scale collapse, and sometimes leaving only a crack; Sometimes it stirs like a raging wave, and sometimes it erodes like a sawtooth; If the advection is slow, it will leave a gentle trace, and if the torrent rolls, it will produce abrupt ornamentation.
As a result, this long canyon is a mixture of good and evil people, some wide and some narrow; Some are like honeycombs; Some are like ant nests; Some are as sharp as pagodas, and some are piled like bricks; Some of them are like a lonely mountain peak, while others are like natural caves. People named these masterpieces of nature according to their shapes and fairy tales, such as Apollo Temple, Di Anna Temple and Brahman Temple.
The "Window of Angels" on the northern edge is a sky-high cave on the mountain, and the "Moral Point" on the southern edge is like the podium of an ancient general, especially the section of the valley wall strata, with clear texture and overlapping layers, just like a curve pattern composed of thousands of books, undulating along the mountain and extending along the valley, and like a Wan Li ribbon, just like a picture on the earth. At this point, tourists all admire the ingenuity of nature.
Extended data:
The horizontal strata of the canyon rock wall are clear and clear, and they are geological deposits hundreds of millions of years ago. Like tree rings, they provide sufficient basis for people to understand geological changes. Not all rocks are hard. Those fragile parts can't stand the impact of wind and rain or rapids, and disappear without a trace after a long time, while the rest are often very strange in shape.
Including natural stone bridges, winding paths leading to a secluded place, two cliff walls standing thousands of miles away, blue sky scenery in hand, and other caves and stone valleys formed by the impact of water flow. Different shapes, red as fire. Every stone seems to be a beautiful painting. Being in it is like coming to a fairyland.
The climate and landscape of the two walls and the bottom of the canyon are very different. The south wall is dry and warm, with few plants. The north wall is higher than the south wall, the climate is cold and humid, and the trees are green; The bottom of the valley is dry and hot, showing a desert landscape. The Colorado River winding at the bottom is deep and curved, and the riverbed gradient of the whole Grand Canyon area is per kilometer 150 cm, which is 25 times that of the Mississippi River.
Among them, 50% of the slope is still very concentrated, creating a fast-flowing landscape of local rivers in the canyon. Because of this, sailing and drifting along the canyon has become a fascinating adventure.
Baidu Encyclopedia-American Grand Canyon