What is EROSION?What is EROSION?

I. ErosionI. ErosionA. Erosion is a process that moves weathered

rock and soil from one place to another.

B. Gravity, Water, Glaciers, Waves, and Wind can all

cause erosion.

C. Weathering produces sediment, but erosion moves it.

D. Deposition lays down the sediment, which changes

the shape of the land.

E. Weathering, erosion and deposition act together in a

cycle that wears down and builds up Earth’s surface.

II. GravityII. Gravity

A.A. Mass movement is the process Mass movement is the process that moves sediment downhill by that moves sediment downhill by gravity.gravity.

B.B. Mass movement can be rapid or Mass movement can be rapid or slow.slow.

C.C. Different types of mass Different types of mass movement include landslides, movement include landslides, mudslides, slumps, and creeps.mudslides, slumps, and creeps.

SlumpsSlumps often occur when water soaks often occur when water soaks the base of a mass of soil that is rich in the base of a mass of soil that is rich in clay. Unlike a landslide, the material in clay. Unlike a landslide, the material in slump moves down in one large mass.slump moves down in one large mass.

III. Water ErosionIII. Water Erosion

A.A. Moving water is the major agent of Moving water is the major agent of erosion.erosion.

B.B. Erosion by water begins with splashes of Erosion by water begins with splashes of rain.rain.

C.C. Through erosion, rivers create valleys Through erosion, rivers create valleys and waterfalls.and waterfalls.

Channels caused by water erosion in the Coconino Sandstone, West Beaver Creek Channels caused by water erosion in the Coconino Sandstone, West Beaver Creek CanyonCanyon

IV. Ice ErosionIV. Ice Erosion

A.A. Ice erosion is caused by the movement of ice, Ice erosion is caused by the movement of ice, typically glaciers.typically glaciers.

B.B. A glacier is any mass of ice that moves slowly A glacier is any mass of ice that moves slowly over land.over land.

C.C. Glaciers can form only in areas where more Glaciers can form only in areas where more snow falls than melts.snow falls than melts.

D.D. Glaciers erode by two processes: abrasion and Glaciers erode by two processes: abrasion and plucking, in which glaciers pick up rocks when plucking, in which glaciers pick up rocks when it moves and carries the rock with it.it moves and carries the rock with it.

Valley Glacier is a long narrow glacier that forms when snow Valley Glacier is a long narrow glacier that forms when snow and ice build up in a mountain valley.and ice build up in a mountain valley.

V. Wave ErosionV. Wave ErosionA.A. Waves are a major force of erosion Waves are a major force of erosion

along coasts.along coasts.

B.B. Waves also erode land by abrasion.Waves also erode land by abrasion.

C.C. Waves can hit rocks along the shore Waves can hit rocks along the shore with great impact and break the with great impact and break the rocks apart.rocks apart.

Makapu Beach ErosionMakapu Beach Erosion

VI. Wind ErosionVI. Wind ErosionA.A. Wind is the weakest agent of erosion.Wind is the weakest agent of erosion.B.B. However, wind is very effective in However, wind is very effective in

causing erosion in deserts.causing erosion in deserts.C.C. The main way wind causes erosion is The main way wind causes erosion is

by picking up small particles of by picking up small particles of sediment, moving it through the air sediment, moving it through the air allowing it to fall back to the ground, allowing it to fall back to the ground, called deflation.called deflation.

D.D. Sand dunes, a deposit of wind blown Sand dunes, a deposit of wind blown sand, are created by wind erosion.sand, are created by wind erosion.