Erosion and Deposition by Gravity - Earth Science in Maine
Water running down all the mountains and valleys is pulled down by this force of gravity. Wind is ultimately a result of air molecules being held to Earth's surface. Gravity is responsible for erosion by flowing water and glaciers. But gravity also causes erosion directly. All the material moves together in big chunks. All rights reserved. Interactive Textbook. Agents of Erosion and Deposition What Is Mass Movement? Gravity can cause erosion and deposition. Gravity.
Gravitational erosion can also directly result in mudslides. When mud, formed high atop a hill or mountain, suddenly pulls away to slide downhill, once again the power of gravity is responsible. A mass of moving mud can wash away large amounts of soil as it streams atop soil's surface, and often dislodges rocks and even large boulders.
If a mudslide is large enough, it can lead to dramatic, immediate changes in the shape of hills or mountainsides. Gravity can also directly cause a phenomenon known as slump, in which large chunks of rock and soil suddenly break off and fall from the side of a hill or mountain. Unlike a landslide, rocks and soil no not roll down the side of a such landforms, but instead fall directly to the Earth below.How do glaciers shape the landscape? Animation from geog.1 Kerboodle
This is how large chunks of mountains and hills can change shape because of slump. Indirect Impacts of Gravity As two of the best-known agents of erosion, neither water nor ice could cause erosion without gravity's help. Gravity's indirect impacts on erosion include pulling rain to the Earth, drawing floodwaters downward and dragging glaciers downhill.
Rain slowly wears down the surfaces of mountains, hills and other landforms with time, but rain does not reach Earth's surface on its own. Rain forms in clouds when water vapor condenses, and gravity pulls it to Earth. Over time, rain loosens soil and the wind blows it away, or the rain creates mud, which typically moves from the highest to lowest points down the side of a mountain or hill. Rain can also wear rocks down with time, though this process often takes millions of years to drastically reshape large landforms.
Glaciers are some of the most powerful agents of erosion. These giant formations of ice and snow moving across different parts of the Earth at different points in history, continue to do so today.
What are the four agents of erosion?
Several million years ago, scientists postulated that glaciers moved across parts of North America, causing major geological changes in what is now the Midwestern United States. Yosemite Valley, located along California's Sierra Nevada mountain range in Yosemite National Park, got its shape when glaciers cut through the range's massive granite, leaving stunning and world-renown features like the sheered off rock-face of Half Dome and the massive El Capitan.
Glaciers' slow and steady movement even flattened certain areas in modern-day Indiana with only a few gorges and elevated landforms left intact. Glaciers move with the help of gravity.
Over long periods of time, the pull of gravity forces them toward lower elevations. Glaciers freeze the land around them, then unfreeze a bit, just enough to move further downhill before freezing again. As this process occurs, glaciers break soil and rock apart, pulling them along while often scratching grooves into the bedrock beneath.
Other Types of Mass Movement Two other types of mass movement are slump and creep.
Both may move a lot of soil and rock. You can learn more about slump and creep at the link below. You can see how it happens in Figure below. All the material moves together in big chunks.
How Does Gravity Cause Erosion? | Sciencing
Slump may be caused by a layer of slippery, wet clay underneath the rock and soil on a hillside. Or it may occur when a river undercuts a slope. Slump leaves behind crescent-shaped scars on the hillside. Slump takes place suddenly, like a landslide. How does slump differ from a landslide? Creep Creep is the very slow movement of rock and soil down a hillside. You can only see the effects of creep after years of movement.
This is illustrated in Figure below. The slowly moving ground causes trees, fence posts, and other structures on the surface to tilt downhill.
Creep is seen on a hillside. What evidence shows creep has occurred? Creep usually takes place where the ground freezes and thaws frequently. Soil and rock particles are lifted up when the ground freezes. When the ground thaws, the particles settle down again.
Each time they settle down, they move a tiny bit farther down the slope because of gravity. Lesson Summary Gravity can pull soil, mud, and rocks down cliffs and hillsides.
This is called mass movement. The most destructive types of mass movement are landslides and mudslides. They occur suddenly and without warming. They engulf everything in their path. Two other types of mass movement are slump and creep.