Mass Movement: What causes the different types of mass movement? 1.
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Transcript of Mass Movement: What causes the different types of mass movement? 1.
Mass Movement:
What causes the different types of mass movement?
1
Erosion is the process by which natural forces move weathered rock & soil from one place to another.
2
What is the material moved by erosion called?
sediment Sediment may include pieces of rock or soil or the remains of plants or animals
3
Agents of ErosionIn nature, sediment can be moved
by:Gravity (Mass Movement)Water (Rivers, Streams, Groundwater)GlaciersWavesWind
These are known as the agents of erosion.(The word ‘agents’ means the processes
or ways that erosion occurs.)
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Deposition * happens where agents of erosion drop or lay down sediment. • Sediment is deposited in:
• Horizontal layers– layers become very thick after a long
periods of time.• Oldest layers on the bottom–Law of Superposition.
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Mass movement * happens when gravity moves sediment downhill.
* can be rapid or slow and is caused by gravity.
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Landslides * are the most destructive of the four
types of mass movement.
* Describe: Rock & soil slides quickly down
steep slopes
* Where does it happen?Where road builders cut through
hills or mountains leaving behind unstable slopes.
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Landslides
http://en.wikipedia.org/wiki/Landslide http://carletong.wordpress.com/2009/04/27/paybacksamother/
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Mudflows* are very dangerous.
* Describe:The rapid downhill movement
of a mixture of water (can be as high as 60%) rock, and soil.
* What may trigger it?Often occur after heavy rains in
a normally dry area.
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Mudflows
http://cache.virtualtourist.com/1827048-City_of_Plymouth_destroyed_by_Mud_Flows-Montserrat.jpg
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Slump * occurs when one huge mass falls
together.
*Describe:Mass of rock & soil suddenly
slip down a slope in one huge mass
*What makes it happen? When water soaks the bottom
of soil rich in clay
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Slump
Cartersville, Georgia12
Creep* is very slow movement.
*Describe:Barely noticeable, you eventually
see the effects of the slow movement in telephone poles, fence posts & trees leaning at odd angles
*What causes creep?From freezing & thawing of H2O in
cracked layers of rock beneath the soil13
Creep
http://images.google.com/imgres?imgurl=http://facstaff.gpc.edu/~pgore/myphotos/other/creep.jpg&imgrefurl=http://facstaff.gpc.edu/~pgore/geology/geo101/masswasting.html&usg=__NXT2vQd6NNlaYppssy5JkhmQtO8=&h=357&w=300&sz=33&hl=en&start=7&um=1&tbnid=T5WrN7ZS1oqFeM:&tbnh=121&tbnw=102&prev=/images%3Fq%3Dcreep%2Bmass%2Bmovement%26hl%3Den%26sa%3DN%26um%3D1
Bent tree trunk illustrating creep. National Zoo, Rock Creek Park, Washington, D.C.
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