EROSION AND DEPOSITION Changing and creating landforms. Copy these notes into your foldable Tape your foldable into your journal

Erosion — the process by which weathered rock and soil (sediments) is moved from one place to another by natural forces.

1.Amount of agent (wind/rain) 2.Length of time (duration) 3.Steepness or slope of land 4.Lack of vegetation The faster the erosion agent, the more sediment can be carried! Factors that affect the rate of erosion: (add inside bottom)

FOUR AGENTS OF EROSION (Causes of erosion) 1. Gravity — moves material downward Gravity is the underlying force for erosion and deposition Examples: Landslides, Rockfalls, Rock slides, Mudflow, Slump and Creep

LANDSLIDE

Rockfall Watch for falling rock!

MUDFLOW:

SLUMP

Creep

2. Wind — wind picks up loose material (sand and dust) and moves it Forms Dunes when wind slows Examples: Sandstorm, dust storm

Wind Erosion Dunes

Wind Erosion can be prevented by the planting vegetation (grass and plants) and creating wind barriers

More Ways to reduce erosion Vegetation – trees around crops Where slopes are steep, terracing is used. Instead of plowing, cattle graze. Water is sprayed on bare soil to prevent wind erosion. Netting and straw to reinforce soil.

3. Glaciers (Ice) — large mass of snow and ice carries sediments and deposits it somewhere else Examples: U-shaped valley, Cirque, Horn, Arete

HORN: 3-4 glaciers started and moved off in different directions

U Shaped Valley

CIRQUE (it’s circular, bowl-shaped)

GLACIAL LAKE

Arete: ridge between glaciers

4. Water (moving water) — greatest agent of erosion. Examples: Rivers, Streams, Runoff (rain water),Waves, Waterfalls, Floods Types of Landforms: V-shaped valley, oxbow lake, delta, beach, barrier island, spit

Young River: V-shaped valley

V-SHAPED VALLEY

Mature River

OXBOW LAKE Old River: Meanders

Deposition — setting down (dropping) of sediments in a new location. Deposition can create new landforms like beaches and sand dunes/bars.

SANDBAR

SOUTH PADRE ISLAND BARRIER ISLAND

BEACH

SPIT

DELTA River

Weathering (breaking) Erosion (carrying or moving) Deposition (depositing or dropping off)