Transcript Weathering and Erosion

Weathering and Erosion
MOVING WATER
• What do we call the movement of water?
– Water Cycle (I hope you didn’t forget)
• How do you think the water cycle causes
weathering and erosion
RUNOFF
• Water moving from
higher ground to
lower ground
because of the pull
of gravity
• What are some of
the sources of
runoff?
– Rain
– Snow melting
Precipitation
• As any form of precipitation hits the
rocks/ground it causes weathering
• Over time precipitation will wear the rock
away until it becomes soil
Precipitation
• Some water seeps in to the ground
• As the water trickles through the soil it
eventually reaches solid rock
• After the rock it reaches other water
sources which then feed the roots
• The water changes all surfaces it comes
into contact with
Physical and Chemical Weathering
• Physical
– Grinding off of small rock particles
• Chemical
– As water moves through rock it can combine
with minerals in rock
– This combination may cause changes in the
original rock and any other rock the mineral
water comes into contact with
Shorelines
• What do you think
shorelines have to do
with weathering?
• As waves wash up on
shore, the sand on the
beach moves.
• The shape of the shore
changes along with the
movement of the water
Erosion
• Water Erosion
– Streams, rivers and rain
erode the Earth’s surface
over a long period of time.
– Water erosion can cause
new landforms.
Erosion
• Valleys
– If water flows into a
stream, over time
that stream will
become a river.
– As river and streams
flow over land, they
cut into the land
– Over time, these
cuts create a valley
– Sometimes the river
dries up but the
valley remains
Erosion
• Canyon
– Deep narrow valleys
with steep sides
– Canyon usually have
rivers or streams
flowing through them
– The Grand Canyon still
has a small river
flowing through it that
has shrunk over time
Canyons and Valleys
Movement of Water
• Fast moving water
– Cut deeper into the
land
• Slow moving water
– Shapes land at a
much slower pace
Meanders
– Looping changes of
direction in a river
or stream
– Water moves
differently around a
bend
– The land near the
outside edge or a
meander erodes
faster than land on
the inside edge
Tributary
• A river or stream that does not reach the
ocean
• Tributaries join other rivers or streams
Wind Erosion
• Wind carries tiny particles
• These tiny particles are then dropped in
other areas changing the landscape
Deposition
• The process of
adding sand, rock or
soil to a new location
• Fast Moving River
– Rock is deposited near
the mouth (where the
river meets the ocean)
of the river
– A DELTA is a low, flat
piece of land at or
near the mouth of a
river
Delta
• Formed by deposition
• As a river flows it erodes small pieces of rock
and soil
• As the water moves the soil and rock continue to
move
• When the water meets the ocean it slows down
causing the rocks and soil to settle at the bottom
of the river
• Deltas are very fertile – great for growing crops
Floods
• When snow melts and the water runs off
into streams, rivers and tributaries
• Floodplain is a flat land near a river form
by deposition during floods
– During a flood water flows over a rivers banks
– When the water leaves the river it slows down
– The rocks and soil are dropped becoming part
of the flood plain
Floodplain and Delta
Found anywhere
along rivers
Continuously
smoothing
Found at the mouth
of rivers