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Erosion & DepositionErosion & Deposition
ErosionErosion
• the process by which natural forces move weathered rock and soil from one place to another
CausesCauses of Erosionof Erosion
• Gravity
• Running water
• Wind
• Glaciers
Causes of ErosionCauses 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 ErosionCauses 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:• LandslidesLandslides—rock & soil
slide quicklyquickly down a steep
slope
Causes of ErosionCauses 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:• MudflowsMudflows—rapid downhill
movement of a mixture of
waterwater, rock, and soil
Causes of ErosionCauses 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:• SlumpSlump—oneone large masslarge mass of
rock and soil suddenly slips
down a slope
Causes of ErosionCauses 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:• CreepCreep—veryvery slowslow downhill
movement of rock and soil
Causes of ErosionCauses of Erosion
• Running Water = #1 agent of erosion
Causes of ErosionCauses of Erosion
• Running Water– #1 agent of erosion
– Types of running water:• StreamsStreams
– Small streams = creeks– Large streams = rivers
Colorado River Grand Canyon
Causes of ErosionCauses of Erosion
• Running Water– #1 agent of erosion
– Types of running
water:• Streams• WavesWaves
Causes of ErosionCauses of Erosion
• Wind = Blows sediment
Dust Bowl
Sand dunes
Causes of ErosionCauses of Erosion
• Glaciers = Large masses of moving ice
– Movement
changes the land
beneathbeneath themAlaska
Deposition
• the natural process of laying down sediments in a new location
– creates new
landforms
Deposition
• the natural process of laying down sediments in a new location
– creates new
landforms:• Oxbow lakeOxbow lake—
deposition
blocks offblocks off
part of a river
Deposition• the natural process of laying down sediments
in a new location
– creates new landforms:
• DeltaDelta—sediment is deposited at the endend 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 Most fossils are found in sedimentary rocks because sedimentary rocks because organisms get covered and organisms get covered and
preserved by the layers preserved by the layers then mineral replacement then mineral replacement
occurs over time.occurs over time.
Weathering, erosion and depositionWeathering, erosion and deposition are all part of a never-ending cycle that are all part of a never-ending cycle that
constantly shapes and reshapes the constantly shapes and reshapes the land.land.
Weathering, erosion and depositionWeathering, erosion and deposition are all part of a never-ending cycle that are all part of a never-ending cycle that
constantly shapes and reshapes the constantly shapes and reshapes the land.land.
DestructiveDestructive forcesforces—break down—break downConstructive forcesConstructive forces—build up—build up
Weathering, erosion and depositionWeathering, erosion and deposition are are all part of a never-ending cycle that all part of a never-ending cycle that
constantly shapes and reshapes the land.constantly shapes and reshapes the land.
ErosionCarries sediment away
DepositionDepositionTakes sediment to a new
location to build new rock layers
WeatheringBreaks down rock
Destructive Forces
Destructive Forces
Constructive Constructive ForcesForces