1. Mass Movement: What causes the different types of mass movement? 1

2. Erosion is the process by which natural forces move weathered rock & soil from one place to another. 2

3. 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

4. Agents of Erosion In nature, sediment can be moved by: Gravity (Mass Movement) Water (Rivers, Streams, Groundwater) Glaciers Waves Wind These are known as the agents of erosion. (The word ‘agents’ means the processes or ways that erosion occurs.) 4

5. 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. 5

6. Mass movement * happens when gravity moves sediment downhill. * can be rapid or slow and is caused by gravity. 6

7. 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. 7

8. Landslides http://en.wikipedia.org/wiki/Landslide http://en.wikipedia.org/wiki/Landslide h ttp://carletong.wordpress.com/2009/04/27/paybacksamother/ 8

9. 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. 9

10. Mudflows http://cache.virtualtourist.com/1827048-City_of_Plymouth_destroyed_by_Mud_Flows-Montserrat.jpg 10

11. 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 11

12. Slump Cartersville, Georgia 12

13. 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 soil 13

14. 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=T5WrN7Z S1oqFeM:&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. 14