Erosion & DepositionErosion & Deposition

EROSIONEROSION

• Erosion= movement of sediment by ice, wind, water, or gravity

• Is erosion constructive, destructive, or both? Why?

CAUSES of EROSION CAUSES of EROSION

Ice (Glaciers)

– Glaciers carry materials along as they move forward

ICE EROSION EFFECTSICE EROSION EFFECTS

ICEa. “U” shaped Valleyb. Flat Plains

CAUSES of EROSIONCAUSES of EROSION

WIND carries

(blows) sediments and soil from one place to another

WIND EROSION EFFECTSWIND EROSION EFFECTSWIND

a.Reshaped surfaces

b.Sand storms c.Dust storms

EROSION EFFECTSEROSION EFFECTS

CAUSES of CAUSES of EROSION EROSION

Moving water in streams & rivers carries sediments along as it moves down stream.– The faster the water, the more and

the heavier material it can carry

WATER EROSION EFFECTSWATER EROSION EFFECTSKARST Landscape

Karst is an area of land that is mostly made of limestone & because of this usually has a lot of caves & sinkholes.

WATER EROSION WATER EROSION EFFECTSEFFECTS

caves

WATER EROSION EFFECTSWATER EROSION EFFECTS

Caves are formed when rock is chemically dissolved and carried away by groundwater or underground rivers leaving “holes” in the rock.

WATER EROSION EFFECTSWATER EROSION EFFECTS

sinkholes

Sinkholes form when the rock underneath the soil, is eroded away & the and above sinks because it is no longer supported

WATER EROSION EFFECTSWATER EROSION EFFECTSRiver valleys & canyonsare formed when fast moving rivers erode the land over long periods of time.

EROSION EFFECTSEROSION EFFECTS

Floodplains are formed over time when a river or stream overflows its regular banks and erodes the land around it.

CAUSES of EROSIONCAUSES of EROSION

• Gravity– Causes water and glaciers to move

downhill– particles (sediments, dust, soil,

etc.) carried by water and wind to settle on bottom on stream or the ground

GRAVITY EROSION EFFECTSGRAVITY EROSION EFFECTS

Mudflows

Landslides

Mass Movement

DEFINITIONSDEFINITIONSDeposition

Brainstorm:

1) What is it?

2) How can deposition change the surface of the Earth?

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DepositionDeposition

• Deposition= build up of land through the dropping off of sediments that are being carried by ice, wind, water or gravity

• Is deposition constructive, destructive, or both? Why?

DepositionDeposition

• Deposition is constructive because it builds up Earth’s surface

DEPOSITION DEPOSITION NONLIVING CAUSESNONLIVING CAUSES

ICE Glaciers deposit sediments as they begin to melt (recede)

DEPOSITION EFFECTSDEPOSITION EFFECTSICE

-moraines

-lakes

-hills

FORCES OFFORCES OFEROSION & DEPOSITIONEROSION & DEPOSITION

WIND

When the wind slows down, the sediments are deposited–The heaviestsediments are dropped first

Deposition EffectsDeposition Effects

• Wind– Sand dunes

DEPOSITION DEPOSITION NONLIVING CAUSESNONLIVING CAUSES

WATER-When the water slows down, the heaviest sediments are deposited first

Older rivers have curves called meanders.

• Canarvon Gascoyne Delta Shark Bay W Australia

DEPOSITION EFFECTSDEPOSITION EFFECTS

WATER

deltasandbarbeac

h

DEPOSITION EFFECTSDEPOSITION EFFECTS

FLOODPLAINS

DEPOSITION EFFECTSDEPOSITION EFFECTS

stalagmites, & stalactites (ground) (ceiling)

WATER

Constructive and Destructive Constructive and Destructive Forces ReviewForces Review

• Destructive– Forces that tear

down/wear away Earth’s surface

– Examples:• Weathering • Erosion

• Constructive– Forces that build

up Earth’s surface

– Example:• Deposition

DEFINITIONSDEFINITIONSErosion

Brainstorm:

1) What is it?

2) What can cause it?

3) How does erosion change the surface of the Earth?

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Possible Types:

– Erosion wears down Earth’s surface

gullyErosion is a destructive force.

river valley