Table of Contents
Which factor influences the mass movement of particles?
Gravity is the main force responsible for mass movements. Gravity is a force that acts everywhere on the Earth’s surface, pulling everything in a direction toward the center of the Earth. On a flat surface, parallel to the Earth’s surface, the force of gravity acts downward.
How does gravity affect rocks and soil particles?
Gravity can cause erosion and deposition. Gravity makes water and ice move. It also causes rock, soil, snow, or other material to move downhill in a process called mass movement. Particles in a steep sand pile move downhill.
What can seep into the soil and rock and increase their weight?
Water can seep into the soil or rock and replace the air in the pore space or fractures. Since water is heavier than air, this increases the weight of the soil. Water can reduce the friction along a sliding surface.
How does plant growth contribute to physical erosion?
Plant growth can also contribute to physical erosion in a process called bioerosion. Plants break up earthen materials as they take root, and can create cracks and crevice s in rocks they encounter. Ice and liquid water can also contribute to physical erosion as their movement forces rocks to crash together or crack apart.
Why are some rocks smoother than others in erosion?
Ice and liquid water can also contribute to physical erosion as their movement forces rocks to crash together or crack apart. Some rocks shatter and crumble, while others are worn away. River rocks are often much smoother than rocks found elsewhere, for instance, because they have been eroded by constant contact with other river rocks.
How are landslides related to the process of erosion?
Landslide s and other forms of mass wasting are associated with physical weathering. These processes cause rocks to dislodge from hillsides and crumble as they tumble down a slope. Plant growth can also contribute to physical erosion in a process called bioerosion.
When does the chemical composition of a rock change?
Chemical erosion occurs when a rock’s chemical composition changes, such as when iron rusts or when limestone dissolves due to carbonation. In physical erosion, the rock breaks down but its chemical composition remains the same, such as during a landslide or bioerosion, when plants take root and crack rocks.