Ch. 9 Lesson 4What is erosion?

erosion• movement of materials from 1 place

• destructive process

landslides• gravity quickly pulls rocks &

dirt downhill

landslide

deposition• placing of the materials in a new place

• constructive process

delta• place where heavy sediments are

deposited when a river meets an ocean

Mississippi River

The Mississippi Delta includes much of coastal Louisiana and Mississippi, including

the metropolitan area of New Orleans.

delta

rocks are ground into sediment under moving glaciers

Rivers can make deep canyons by erosion.

Grand Canyon

• waves, sand & gravel break rocks• form harbors & inlets- erode more

quickly than other areas• harbors= areas that are protected

from ocean waves

wave erosion

sand erosionsand erosion

•wind blows dust, soil or sand from 1 place to another

•makes sand dunes

wind erosion• winds blow topsoil from fields

• farmers surround fields with tall trees

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