Weathering, Erosion

1
Weathering, Erosion, Deposition
2
Remember Weathering is

• the breaking down of rocks
• There are two types of weathering mechanical
  weathering chemical weathering.
• Weathering happens to rocks that are NOT MOVING.

These rocks have been blasted by wind and sand
causing them to become rounded. ABRASION
3
Erosion

• is the process by which weathered rock and soil
  are moved  from one place to another.
• Erosion carves the Earth's surface creating
  canyons, gorges, and even beaches.
• There are 4 agents of erosion
• gravity
• water
• wind
• glaciers

4
Deposition

• is the process by which sediments (small
  particles of rock) are laid down in new
  locations.
• Deposition builds new landforms AND changes the
  shape of the land.
• Water is usually responsible for deposition but
  landslides can be caused by earthquakes and
  volcanoes.

5
Water as an Erosion Agent

• can erode great amounts of sediment (broken
  pieces of rock)
• Ex. Waves carry weathered rock from cliffs
  deposit it as new sand on beaches.
• Ex. Rain carries sediment into rivers streams

6
Weathering, Erosion, Deposition

• These 3 work together in a continuous cycle that
  BOTH wears down builds up Earths surface.
• Forces that build up Earths surface are called
  constructive forces.
• Forces that tear/wear down Earths surface are
  called destructive forces.
• Sometimes erosion deposition work slowly, other
  times like in a thunderstorm or a flood they work
  quickly.
• These 3 are NEVER ENDING!

7
Erosion

• The main thing that causes erosion is water.
• In this picture the running water eroded the
  sides of this canyon and created the V-shaped
  valleys.

8
Mass Movement

• Is one of several processes by which gravity
  moves sediment (pieces of rock) downhill.
• Mass movement can be SLOW or FAST.
• Gravity causes mass movement.
• Gravity moves rock other materials down hill!
• 4 types of mass movement (landslide, mudslide,
  slump, creep)

9
Landslides

• Are the MOST destructive kind of mass movement.
• Landslides- are when rock soil slide quickly
  down a slope.
• Landslides are common where roads have been cut
  through hills or mountains.

10
Mudslides

• are fast, downhill movement of a mixture of
  water, rock, soil.
• Mudslides often happen after heavy rains.

11
Slump

• Mass movement in which a mass of rock soil
  suddenly slip down a slope in 1 big motion or
  mass.
• Slump can look like a giant spoon has started to
  scoop a mass of soil rock out from a hillside.

12
Creep

• Is a very slow downhill movement of rock soil.
• Creeps are so slow, that you will hardly notice
  it, but you can see the effects of creeps in
  telephone poles, gravestones, mail box posts,
  fenceposts.

13
Creep
14
Landslide, Mudslide, Slump, or Creep?
15
Landslide, Mudslide, Slump, or Creep?
16
Landslide, Mudslide, Slump, or Creep?
17
Landslide, Mudslide, Slump, or Creep?
18
Landslide, Mudslide, Slump, or Creep?
19
ErosionThe first five pictures of this
presentation are of the same rock, just in
different time periods. Pay attention to the
dates on the side of the pictures and see what
the water did to this rock.
1890
20
Still the same rock.
1910
21
Still the same rock
1920
22
Still the same rock.
1970
23
Still the same rock, but where did it go?
1990
24
Here is another picture of what erosion caused.
25
The ground has been washed away by water. Thats
erosion.
26
Critical Thinking ???

• Why is weathering so important to life on land?
• Explain why water erodes Earths surface more
  than wind does?
• What are ways in which people cause erosion? What
  can we do to prevent erosion?