Download Erosion and Deposition PPT

Weathering, Erosion, and
Deposition
Forces wear down and build up Earth’s
surfaces
Water erosion and a farm field
Natural Forces move and deposit
sediments
The Grand Canyon
was formed by the
movement of water
Water flowed over
the land and carried
away weather rock
and soil
This shaped a
valley where water
flowed creating the
canyon
Weathering
◆ Weathering
is the process by which
natural forces break down rocks.
◆ There
are two types of
weathering, mechanical and
chemical.
Weathering
◆ Mechanical
Weathering is the
breaking up of rocks by physical
forces
◆
Ice wedging, pressure release, plant growth,
or abrasion
◆ Chemical
Weathering is the
breakdown of rocks by chemical
reactions that change the rocks’
composition.
◆
Dissolving or rusting
Weathering
Waves and Wind Shape the Land
What natural force
created these isolated
stone pillars?
The movement of water
(waves). The constant
action of waves
breaking against the
cliffs slowing wore the
rock cliff away
Erosion and Deposition
◆ Erosion-
weathered particles are
picked up and moved to a new place
◆ Deposition-
the part of the erosion
process in which sediment in placed
(deposited) in a new location
Gravity
◆ Gravity
is the force holding
everything down on Earth
– This force causes water to move
downward (think from the top of a
mountain to the bottom)
– In the process it carries and deposits
sediment in new places
Three types of Erosion
◆
◆
◆
Water erosion- rivers, streams carry
sediment and deposit sediment at river
bottom, floodplain, and mouth of the river
Wind erosion- Strong winds life tiny particles
of dust and carry them long distances
Ice erosion- As ice moves slowly it carries
with it rock and soil particles frozen inside of
the ice
Valleys and Floodplains
As streams flow and carry sediment from the surface of
the land they form valleys
Floodplain- area of land on either side of the stream that
is underwater when the stream floods
Erosion
Deposition
Alluvial Fan- fanshaped deposit of
sediment at the
base of a mountain
formed from a
stream
Delta- an area of land formed
by the buildup of sediment at
the end (mouth) of a river
Deposition
Sandbar- a ridge of sand
built up by the action of
waves →
Barrier Islands- a sandbar that
builds up over time creates a
long narrow island parallel to
the coast ←