1. Earth’s Surface
Erosion

2. Vocabulary
Erosion- the process that wears down and carries away rocks and soil

3. Erosion Gravity acts as a force of erosion by causing a mass movement
Mass movement- a process that moves sediment down a hill
There are 4 ways a mass movement may occur

4. Mass Movement
Landslide- a rapid movement of large amounts of rock and soil

5. Mass Movement
Mudflow- a rapid downhill movement of a mixture of water, rock and soil

6. Mass Movement Slump- mass of rock and soil suddenly slips down a slope
This is different from a landslide because it comes down in one large mass

7. Mass Movement Creep- a very slow movement of rock and soil
Usually creeps cause objects to sit at unusual angles

8. Water Erosion Stream- a channel along which water continually flows
River- a large stream usually forming from several streams flowing together

9. Features of Streams
Flood Plain- a flat area along a stream that is entirely covered only during times of floods
Meander- the winding and bending of a stream as it erodes the land
Only older streams do this
Oxbow Lake- when sediment builds up, cutting off the meander from the rest of the river, causing a separate, curved lake

10. Water Erosion
Fast moving rivers that are straight and narrow cut steep slopes and create a V-shaped valley
Example- Grand Canyon

11. Grand Canyon

12. Water Erosion
Waterfall- a river cuts through soft rock faster than hard rock
Example- Niagara Falls

13. Niagara Falls

14. Groundwater Erosion A form of chemical erosion
Makes caves and sinkholes
CAVE- limestone erodes away, leaving behind a dry narrow passage
SINKHOLE- weakened limestone where the entire portion of the ground suddenly collapses

15. Glacial Erosion Glaciers erode land in 2 ways
Plucking- as a glacier flows over land it picks up rocks
Abrasion- gauges and scratches in rocks as a glacier drags across land
Causes large, bowl shaped valleys called cirques
Cuts U-shaped valleys in landforms
May leave behind large, cold glacial lakes

16. Wind Erosion Deflation- wind picks up and carries away small particles
The faster the wind, the larger the particles it can carry
Example- Sand dunes