Erosion & Deposition

Erosion

• the process by which natural forces move weathered rock and soil from one place to

another

Causes

of Erosion

• Gravity • Running water • Wind • Glaciers

Causes of Erosion

•

Gravity =

force that moves rock and other materials

downhill

–

Mass movement

—process of moving sediment downhill – May be fast or slow

Causes of Erosion

•

Gravity

– Force that moves rock and other materials downhill – Mass movement—process of moving sediment downhill – May be fast or slow –

Types of mass movement:

•

Landslides

—rock & soil slide

quickly

down a steep slope

Causes of Erosion

•

Gravity

– Force that moves rock and other materials downhill – Mass movement—process of moving sediment downhill – May be fast or slow –

Types of mass movement:

•

Mudflows

—rapid downhill movement of a mixture of

water

, rock, and soil

Causes of Erosion

•

Gravity

– Force that moves rock and other materials downhill – Mass movement—process of moving sediment downhill – May be fast or slow –

Types of mass movement:

•

Slump — one large mass

of rock and soil suddenly slips down a slope

Causes of Erosion

•

Gravity

– Force that moves rock and other materials downhill – Mass movement—process of moving sediment downhill – May be fast or slow –

Types of mass movement:

•

Creep — very slow

downhill movement of rock and soil

Causes of Erosion

•

Running Water = #1

agent of erosion

Causes of Erosion

•

Running Water

– #1 agent of erosion Colorado River Grand Canyon –

Types of running water:

•

Streams

– Small streams = creeks – Large streams = rivers

Causes of Erosion

•

Running Water

– #1 agent of erosion –

Types of running water:

• • Streams

Waves

Causes of Erosion

•

Wind =

Blows sediment Dust Bowl Sand dunes

Causes of Erosion

•

Glaciers =

Large masses of moving

ice

– Movement changes the land Alaska beneath them

Deposition

• the natural process of laying

down

sediments in a new

location

– creates

new landforms

Deposition

• the natural process of laying

down

in a new

location

sediments –

creates new landforms:

•

Oxbow lake —

deposition

blocks off

part of a river

Deposition

• the natural process of laying

down

in a new

location

sediments –

creates new landforms:

•

Delta —

sediment is deposited at the

end

of a river

Deposition

• deposited sediments are laid down in

layers

• layers of sediment are

compacted

under pressure and eventually form

sedimentary

rock

Deposition

• • deposited sediments are laid down in

layers

Layers of sediment are

compacted

under pressure and eventually form

sedimentary

rock Sedimentary rocks are like ogres and onions…they have

layers

.

Deposition

• • deposited sediments are laid down in layers Layers of sediment are compacted under pressure and eventually form sedimentary rock

Most fossils are found in sedimentary rocks because organisms get covered and preserved by the layers then mineral replacement occurs over time.

Weathering, erosion and deposition

are all part of a never-ending cycle that constantly shapes and reshapes the land.

Weathering, erosion and deposition

are all part of a never-ending cycle that constantly shapes and reshapes the land.

Destructive forces

—break down

Constructive forces

—build up

Weathering, erosion and deposition

are all part of a never-ending cycle that constantly shapes and reshapes the land.

Destructive Forces

Weathering

Breaks down rock

Destructive Forces

Erosion

Carries sediment away

Constructive Forces

Deposition

Takes sediment to a new location to build new rock layers