Weathering and Erosion Notes part 2
EROSION
The process by which natural
forces move weathered rock(sediment) and soil(the final end product of
weathering) from one place to another.
Agents of erosion
There are 4 main types of
erosion- mass movement,
water, wind, and glaciers.
1. Mass
Movement- any process that moves
sediment downhill. The driving force
behind mass movement is GRAVITY.
a. Landslides- most destructive type of mass movement.
Occurs when rock and soil move quickly down a steep scope.
Triggered
by earthquakes, construction.
b. Mudflow-
rapid downhill movement of mixture of water, rocks and soil. Often occur when there have been heavy rains
in normally dry areas. Clay soils flow
the easiest.
c. Slump-
When a mass of rock and soil suddenly slips down a slope in one large
mass. It looks scooped out. Can happen when water soaks underlying clay
soil.
d. Creep-
Very slow downhill movement of rock and soil. Trees may be tilted and other objects
displaced. Result of freezing and
thawing of water in cracked layers of rocks beneath the soil.
2. Wind-
movement of sediment by blowing wind.
As wind speed increases the size of the sediment that the
wind can move increases. Land forms and
sediments blown by the wind may appear frosted.
Occurs most frequently in areas where there is a lot of loose sediment,
like the desert or other arid environments.
3. Glaciers-
movement of sediments of all sizes including boulders by moving sheets of
ice. Can be either valley glacier or ice
sheet. Please refer to online HW
assignment for more glacier information.
4. Water-
moving water is the major agent of erosion on the earth.
a. Run-Off-
the water that moves across the earth’s surface.
Factors affecting run-off:
1. amount
of rain- lots of rain=lots of run-off
2.
vegetation- few plants around=lots of run-off
3. type of
soil- clay soil=lots of run-off
4. slope of
land- steep land=lots of run-off
5. Land
use- man made features like parking lots, cleared land
etc, all increase run-off.
To stop run-off you must have a way to increase the
mount of
water that sinks into the ground.
b. Groundwater-
water that sinks into the ground and moves beneath
the
surface.
-causes
erosion throu chemical weathering-carbonation
-forms
caves, stalagmites and stalactites
-karst topography