Download Weathering, Erosion, Deposition

Erosion and Weathering
What is erosion?
• (geology) the mechanical
process of wearing or grinding
something down (as by
particles washing over it)
• The wearing away of the
earth’s surface by natural
processes
• corrosion: erosion by chemical
action
Types of Erosion
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Water
Wind
Glacier
Soil
Sea
Water
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Occurs from chemicals in the
water and the force and flow of
water
•
Chemicals break down certain
rocks like limestone or chalk
•
Force of water creates cracks and
crevasses
•
These get bigger and bigger as it
gets eroded, particles of the rock
get carried in the water and further
aid erosion
Wind
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The wind picks up smaller particles of rock
(pebbles and sand)
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These hit landforms and take pieces off
them
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This friction causes the break up of
landforms
Glacier Erosion
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What is a GLACIER?:
A huge mass of ice slowly flowing over a land mass,
formed from compacted snow in an area where snow
accumulation exceeds melting
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These large bodies of ice that pick up
rocks and earth and erode the earth’s
surface
Powerful eroding machine, picking up
pieces of rock the size of houses in
some places
Glaciers are so powerful they can
carve valleys and create landforms
Sea Erosion
•
Salts and other chemicals in the water
erode coastal rocks
•
These are dragged out to sea and
deposited in other areas (Long shore
Drift)
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Wave power creates erosion. Also
particles of rock and sediment aid to
the erosion process
Soil Erosion
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Biggest problem for farmers
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Wind and rain remove topsoil and
nutrients
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Makes the soil infertile and it breaks
up leaving dongas
Deposition
Definition
• Deposition- the process in which sediment
is laid down in new locations
– The end result of erosion
Water Deposition
• Alluvial fan- fan shaped deposit of
sediment on land
– Usually form when a stream slows down and
enters a flat plain
• Delta- sediment from a stream deposited
where a river enters a large body of water
– Triangular shape
Alluvial fan and Delta
Glacial Deposition
• As a glacier melts, it creates landforms by
depositing its sediment load
– Till-unsorted mixture of sediment containing
fragments of various sizes
– Moraine-mounds of sediment at the downhill
end of the glacier and along its side
• Long Island is a glacial moraine
Till and Moraines
Wind Deposition
• Sand dunes- large deposits of sand
dropped from wind
– Sand dunes can move as the wind picks up
sand from the back of the dune and blows it to
the front
Sand Dunes