Erosion & Deposition
DEFINITIONS
Erosion
-
Brainstorm:
1) What is it?
2) What can cause
it?
Possible Types:
3) How does erosion
change the surface
of the Earth?
EROSION
• Erosion= movement of sediment by
ice, wind, water, or gravity
• Is erosion constructive, destructive, or both?
Why?
Erosion is a destructive force.
– Erosion wears down
Earth’s surface
river valley
gully
CAUSES of EROSION
Ice (Glaciers)
– Glaciers carry materials
along as they move
forward
ICE EROSION EFFECTS
ICE
a. “U” shaped Valley
b. Flat Plains
CAUSES of EROSION
WIND carries
(blows) sediments
and soil from one
place to another
WIND EROSION EFFECTS
WIND
a.Reshaped surfaces
b.Sand storms
c.Dust storms
EROSION EFFECTS
CAUSES of
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 EFFECTS
KARST 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 EFFECTS
caves
WATER 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 EFFECTS
Sinkholes form when the
rock underneath the soil,
is eroded away & the
and above sinks because
it is no longer supported
sinkholes
WATER EROSION EFFECTS
River valleys & canyons
are formed when fast moving rivers erode
the land over long periods of time.
EROSION EFFECTS
Floodplains
are formed
over time when a river or
stream overflows its
regular banks and erodes
the land around it.
CAUSES 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 EFFECTS
Mass Movement
Mudflows
Landslides
DEFINITIONS
Deposition
Brainstorm:
1) What is it?
2) How can
deposition change
the surface of the
Earth?
-
Deposition
• 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?
Deposition
• Deposition is constructive because it
builds up Earth’s surface
DEPOSITION
NONLIVING CAUSES
ICE
Glaciers deposit
sediments as they
begin to melt (recede)
DEPOSITION EFFECTS
ICE
-moraines
-lakes
-hills
FORCES OF
EROSION & DEPOSITION
WIND
When the wind slows
down, the sediments are
deposited
– The heaviest
sediments are
dropped first
Deposition Effects
• Wind
– Sand dunes
DEPOSITION
NONLIVING 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 EFFECTS
WATER
delta
sandbar
beach
DEPOSITION EFFECTS
FLOODPLAINS
DEPOSITION EFFECTS
WATER
stalagmites, & stalactites
(ground)
(ceiling)
Constructive and Destructive
Forces Review
• Destructive
– Forces that tear
down/wear away
Earth’s surface
– Examples:
• Weathering
• Erosion
• Constructive
– Forces that build
up Earth’s surface
– Example:
• Deposition