The Grand Canyon 



Several proofs have recourse to the divine to describe the magnificence of the Grand Canyon. Some have seen there "the will of God", others "the universal Judgment of the nature". It is true that none definition can't retranscribe the beauty of the lanscape. The Grand Canyon is so imposing that, facing it, the man feels crushed.

© Nicolas


It's in the end of the XIXth centuries that the America starts to discover the magic of the nature. Until now, the big spaces of the West were simply considered as grounds to conquer. But the Grand Canyon has been known of the white man since 1540. It's the captain Garcia, a Spannish conqueror, who discovered this savage immensity. He has been send towards the North by the vice-king of tthe Mexico in search of the seven legendary gold cities of Cibola. Useless to say that his disappointment was big when, instead of these cities full of treasures, he ran across the Grand Canyon.

During the following centuries, the only white visitors were missionaries, solely preoccupied by the conversion to the Christianity of the aboriginal populations navajo et hopi. In 1869, the Regimental Adjutant John Wesley Powell was the first to descent the rapids of the Colorado. The expedition lasted 3 months and on the 9 persons, three perished. It's thanks to his narratives, that the geologists started to take an interest in the places.

In 1901, the railway reached the South bank. Shortly afterwards, one unveiled the hotel El Tovar. But most of the visitors came then to hunt, especially the President Théodore Roosevelt. More than 600 pumas were killed in less than 5 years. Fortunately, the hecatomb came to an end in 1919, date of creation of the national parkbelonging to the Grand Canyon National Park. It is today visited by more than 5 million of tourists by year.

The cliffs offer many panoramic points of view. One has given names evoking divinities to these natural sculptures : the "temple of Diana" or the "temple of Shiva". The places are sacred for the Hopi, persuaded that the spirits of their ancestors live there. Situated in Arizona, this place is of a great interest for the geologists. The Grand Canyon is relatively recent ! It seems that the work of erosion of the river should begun there were about six million years. Besides the subsidence of the waters of the river, the level of the plateau of the Colorado is gone up, accentuating thus the action of the river.

The rocks superposed themselves on nearly 1,5 billion years. The oldest ones date from 1,7 billion years. The horizontal layers of rocks permit to the geologists to reconstituate the history of this region on the four principal geological eras : the precambrian, the paleozoic, the mesozoic and the cenozoic.

From the top of the plateau of Kaibab, which overlooks the Grand Canyon, any observer can locate footprints of corals, of shellfishes or fossilized fishes.

The Colorado, length of 2 333 km, has created the most extraordinary canyon of the world. It flows in making a hundred of rapids at bottom of a gorge, deep of 1 500 meters, length of 447 meters and broad of 549 meters in its most tightly part and can reach 30 km. The average flow of this river is of 650 m3 of water by second. The river has dug  more than 1 600 km of canyons. The most spectacular is of course the Grand Canyon. This river is born of the melting of snows in the Rocky Mountains. Its erosive strength become evident clearly on the sedimentary rocks. Shaped by the river, the beautiful rocky cliffs of the Grand Canyon are protected by the aridity of the desert climate. But the South and North banks of the Grand Canyon constitute two distinct universes. The South bank is mainly a desert. The vegetation is adapted to this dry climate : juniper of the Utah, stone pine, cactus. The North bank is, it, more humid and colder. So, its vegetation is richer with forests of conifers.

When one thinks of the Grand Canyon, one imagines right away a very desert region. But, the climate is very particular. The snow hunted by the storm settles on the walls of the Grand Canyon. When the atmospheric temperature is low, the clouds can be formed of ice crystals. The precipitations take thus the form of snow falls. Some local winds appear only at some moments of the day. It's the case of the katabatic winds (wind blowing from the canyon to the heights). During the night, the fall of the temperatures provokes the condensation of the humidity. In diving into the valley, the cold fog generates a katabatique wind which hunts the warm air. It's so naturally that the composition of the fauna of the two banks presents differences.

Some species live on the two sides. It's the case of the coyote, the puma, the lynx and the goat of the Rocky Mountains. In summer and in automn, the goat of the Rockys stays solitary. The rest of the year, it lives in little herds. The number of coyotes in the park is in cleaner augmentation. It should even have made arrangements to limit it the population.
On the other hand, others occupy only one bank
. The South bank shelters a very rare subspecies of pit viper. It exists two species of squirrels which, each, occupies a side. The squirrel of Kaibab lives on the North bank, whereas the squirrel of Albert occupies the South bank. It is necessary to two species which have evolved in a distinct way from a common ancestor. In the airs, one has counted up more than 300 species of birds. The Grand Canyon particularly sherlers a sixty of couples of peregrine falcons. They share their space with the prairie falcon.



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