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. |
After the glacier occupying a valley melts, the valley displays a steep U-shaped cross section. The walls of the valley are plucked clean but moraine material is left along the sides of the valley (lateral moraine), and in the region of the farthest reach of the glacier (terminal moraine). In this view, talus can be seen on the slopes, and mounds (tree-covered moraines) are visible. Stream meanders are visible on the valley floor, which has been cut nearly level by the action of the glacier. 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. |
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