The Changing Earth essays

The Changing Earth essays Erosion is the transportation of weathered pieces of bedrock through the agents of wind, water (rivers and ice), and gravity. As mountains are built up by tectonic forces, they are also broken down and carried away by weathering and erosion. The pull of Gravity makes surface material move downward. Downslope movements may be rapid or very slow. They may involve only the surface material, or they may involve the bedrock underneath. Houses built on hills can contribute to soil movements because the weight of the homes may add to the gravitational force. Wind contributes to the erosional process by carrying surface material from one location to another. Glaciers, huge sheets of ice that can move slowly over land, pick up and carry rocks and soil with them. When they pass through river valleys, the glaciers deepen those valleys. Mountain Glaciers, coupled with the downward force of gravity, create avalanches that can cause great erosional damage. Of all the erosional agents, running water is the most powerful. Rivers, working with the force of gravity, have devastating erosional impact. The action of rivers flowing against the land has formed gorges as large as the Grand Canyon. As rivers erode land, they carry deposits with them. DELTAS are formed at the mouths of rivers that empty into a lake or an ocean. The soil that is carried along a river and deposited as its mouth is the richiest and most fertile of all soils. The Nile and the Mississippi Rivers have formed deltas that are noted for their rich soil, making these regions highly desirable for agriculture. ...