12/17/2008
Sources of Erosion
Chapter 7
Erosion
Water
Gravity
Glaciers
Wind
Sources of Erosion
Sources of Erosion
Water
Gravity
Glaciers
Wind
Water
Gravity
Glaciers
Wind
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12/17/2008
Sources of Erosion
Water
Gravity
Glaciers
Wind
What is erosion?
Erosion – the wearing away of a surface,
moving material from one place to
another.
What happens with that material?
Deposition – dropping of eroded
sediments.
What is erosion?
7-1 Gravity
Mass wasting – the moving of materials
caused by gravity.
Slump
Creep
Rockslides
mudslides
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Types of mass wasting (pg 174)
Type of
mass
movement
Sediment Size
Speed
Evidence on
the land
Slump
Didja get it?
1.
2.
3.
Creep
4.
Rockslide
5.
mudslide
7-3 Erosion by glaciers
Gravity – Glaciers – Wind – Water
Mass wasting is erosion caused by what?
Which mass movements are very slow?
Which mass movement leaves utility
poles leaning to one side?
What is the difference between a
rockslide and a mudslide?
When the erosive force runs out of
energy, what happens to the sediment it
is carrying?
What is a glacier?
Glacier is a compacted collection of snow
and ice, melting together.
1. What is a glacier?
2. Compare valley and continental
glaciers?
3. How do glaciers cause erosion and
deposition?
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Continental Glaciers
Predict how Long Island (NY)
formed.
Glaciers that
cover large
portions of
the earth’s
surface.
Especialy
grow during
ice ages.
Compare the shape of these two
valleys. Predict how they formed?
Valley Glacier
Valley Glacier – a glacier that forms in a
valley in a mountain.
Evidence: U shaped valley.
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How do glaciers cause erosion?
How do glaciers cause erosion?
By moving!
Plucking – boulders, sand, rocks being
added to bottom of a glacier.
By moving!
Stuff it bulldozes ahead as it is moving is
called Moraine.
Stirations
Groves
Cirque
Arete
How do glaciers cause deposition.
Till – stuff left behind when a glacier
melts.
Outwash – material deposited from
melting glacier water.
How do glaciers cause deposition.
Outwash – material deposited from
melting glacier water.
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Learning Check
7-3 Erosion by glaciers
1. What is a glacier?
2. Compare valley and continental
glaciers?
3. How do glaciers cause erosion and
deposition?
Wind erosion
Deflation
Occurs when wind picks up loose
material and transports it to other places.
Gravity – Glaciers – Wind – Water
Wind blows across fine sediments, leaving
behind the heavy sediments
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Abrasion
Occurs when windblown sediment erode
rocks.
Reducing wind erosion
Windbreaks
◦ Trees around a farm
◦ buildings
Normally, soil is to heavy for the
wind to carry it…
Sand Storm – deserts
Dust Storm – dry soil
Depostion by wind
Loess
◦ Wind deposits of fine grain sediments.
Roots
◦ Grasses, hold soil together.
Keep soil damp
◦ Soil out back being kept damp, to keep from
blowing away.
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Deposition by wind
Dune Migration
Dunes
◦ Form when sediment in air hits an obstacle,
and then falls out.
Now is it a little clearer?
What is erosion?
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Is it part of Erosion or Deposition?
Word
Erosion or
Deposition
How it works?
Trick to
remember it
Mass
wasting
Slump
Creep
Rockslides
Mudslides
U shaped valley
Plucking
Moraine
Till
Outwash
Deflation
Abrasion
Dust
Storm
Sandstorm
Loess
Dune
TRY PROBLEMS 11-10 ON
PAGE 198 ON A
QUARTER SHEET.
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