Copyright Information: All images are in the public domain and available for free. If you use this image, credit NOAA/NGDC, John Lockridge, Longmont, Colorado. |
In fairly recent geologic times, slippage began to occur along a fault in the rocks. A large block of earth, 15 miles from east to west and 40 miles from north to south began to move upward. The block rose most rapidly on the east side and so was tilted to the west. As the Teton Range was being uplifted, water and frost wedging began to remove the topmost layers and expose ancient gneiss and schist. V-shaped valleys were formed. Then a change in the climate brought the onset of the Ice Ages. Glaciers sculpted the peaks and carved U-shaped valleys, leaving the mountains in their present magnificent form. A glaciated valley is visible on the left in this view. It still has a glacial remnant in it. Image Credit: John Lockridge, Longmont, Colorado. The hydrologic system, which includes all possible paths of motion of Earth's near-surface fluids including air and water, is largely responsible for the variety of landforms found on the continents. Heat from the sun evaporates water from oceans, lakes, and streams. Although most of the water returns directly as precipitation to the oceans, some of the water is recipitated over land as rain or snow. If it is precipitated over land, it then begins its journey back to the sea as "runoff." The relentless action of surface runoff, streams, and rivers, glaciers, and waves sculpts the rock into intriguing and bizarre shapes. This set of slides includes examples of wave erosion, wind and water erosion, valley shapes, and glacial rosion. The views are often dramatic. Many were taken at U.S. National Parks and Monuments. |
|
