科罗拉多大峡谷The_Grand_Canyon概要.ppt

Welcome to the Grand Canyon ! vision The Grand?Canyon?in Arizona is one of the largest and most beautiful of all canyons. It extends four hundred fifty kilometers. vision vision When you reach its edge …… nothing else in the world. vision Hundreds of?rocky?points rise from the bottom of the Grand Canyon. so beautiful ! vision Forty million years ago, the Colorado River began cutting through the area. At the same time, the surrounding land was pushed up by forces deep within the Earth. Rain, snow, ice, wind, and plant roots rubbed away at the top of the new?canyon. Below, the flowing?river continued to?uncover?more and more levels of ancient rock. Walls of rock fall away sharply at your feet. In some places, the?canyon walls are more than a kilometer deep. vision vision the Colorado River. On the other side, sunshine lights up the naked rock walls in red, orange, and gold. The bright colors are the result of minerals in the rocks. . vision Their?appearance?changes endlessly -- with the light, the time of year, and the weather. sunset vision blue, purple, green. vision The climate winter you may find cold winds and snow at the top…… spring But at the bottom, you may find warm winds and flowers. Several kinds of plants and animals are found in the?canyon?and nowhere else on Earth. Because the?canyons environments are so different, these?species?did not?spred beyond the canyon, or even far within it. vision The Hopi, the Paiute, the Navajo and other Native American tribes have all been in the area for at least seven centuries.? However, much of what we know today about the Grand?Canyon?was recorded by John Wesley Powell. In eighteen sixty-nine, he became the first white American to explore?much of the?canyon. History vision Today, the Grand?Canyon?is known as one of the seven wonders of the natural world. About five million people visit the Canyon each year. Americas National Park Service is responsible