The History of Grand Canyon

Introduction

The Grand Canyon is a deep ravine (canyon) eroded by the Colorado River in the USA. It is one of the world's most spectacular features and one of the deepest gorges. The scale of the Grand Canyon is impressive. It is 6-29 km/4-18 mi wide, 350 km/217 mi long, and, in places, over 1.7 km/1.1 mi deep. There have been many ideas as to how the canyon was formed. The most accepted is that the Colorado River carved its route while flowing across softer rocks that once covered the region. It maintained its course as it cut deeper into the softer rocks and uncovered the harder, more resistant rocks of the Kaibab plateau. This is known as superimposed drainage. Earth movements that caused the Kaibab plateau to be raised were slow enough to allow the Colorado River to maintain its course. Thus it went from lowland through upland and back to lowland again.

The canyon reveals many rocks, including limestone (at the rim), and then going down through sandstone, shale, more limestone, sandstone, shale, quartzite, dolomite, and schist. The resistant rocks protrude out into the canyon. As a result of the low rainfall, there are few tributary streams and the plateau remains quite smooth (Samson, p.23-35). The combination of hard, resistant rocks and low rainfall means that current rates of erosion are very small. Hence the canyon can retain its sharp-edged shape at the rims. Weathering does occur on the slopes, but the river transports the weathered material away, and so the canyon has retained its shape. However, in 1963 the Glen Canyon Dam was built. This has decreased the amount of material transported by the river, which, because it is now controlled, moves quite slowly. Hence weathered material and debris are growing in the canyon. The Grand Canyon is changing its shape (Mine, p.20-23). Over 5 million people visit the Grand Canyon every year. Of these 500,000 fly, over it and 500,000 go into the canyon. Only 10% of visitors go the north rim. Hence most of the visitors are concentrated at the south rim. The number of cars visiting the Grand Canyon is causing environmental problems such as diesel pollution, the growth of petrol stores, smog, and noise pollution.

The History

In 700-800 AD Anazazi, the native Indians lived in the Grand Canyon. They made their residence in the eastern part of Grand Canyon. There was a group named Cohonina lived in the west of the canyon. These Native Americans left the Grand Canyon approximately in 1150 AD because of some climate changes, there might be passivity of a drought that time. Anazazi and Cohonina both had different life style from each other, but they remained close to each other without any disputer. Their professions changed according to seasons, and they primarily were dependent on hunting and gathering. Being old society, they do not had any technology that time. Agave and roasting pits were used by them. These things found in the area where they lived.

The Anazazi used ...