Transcript Weathering, Erosion, and Deposition

Weathering,
Erosion, and
Deposition
1. Weathering
• Weathering is the breakdown of
rock at the Earth’s surface.
• Some of these changes happen
quickly and some happen slowly.
• There are 2 Types:
– Mechanical and Chemical
2. Mechanical Weathering
 Mechanical Weathering – the type of
weathering where rock is broken down
into smaller pieces without changing
the chemical properties of the rock.
 This can be caused by freezing and
thawing, release of pressure, growth
of plants, and actions of
animals (including
humans).
3. Freezing and Thawing
• Example:
– Water seeps into a
crack in a rock
– When the water
freezes, it expands
– The force of the water expanding causes the
rock to crack more.
– This is called ice wedging
4. Plant Growth
• Roots of trees and
other plants enter into
cracks of rocks.
• As the plants get
bigger, so do the
roots.
• The growing roots force
the cracks further
apart.
5. Abrasion
• Abrasion is the
grinding away of
rock by other rock
particles.
• These particles scrape
away at other rocks
like sandpaper on
wood as they rub or
roll against the
surface.
6. Chemical Weathering
• Chemical weathering is the
processes of breaking down
rock through chemical changes.
• 5 things that cause chemical
weathering: water, oxygen,
carbon dioxide, living organisms
(like lichens) and acid rain.
• Chemical weathering occurs more
rapidly in warm wet climates.
7. Chemical Change
• Chemical Weathering causes the rock to
experience a chemical change (changes its
makeup)
–
–
–
–
Water dissolves rocks over time
Oxygen causes oxidation (rusting)
Acid rain reacts with marble and limestone
Living organisms – plant roots produce weak
acids to dissolve rock around the roots,
ACID RAIN
OXIDATION
CHECK- UP
What type of weathering do
each example cause?
1. The roots of a plant
2. An animal scratching
3. Oxygen
4. Water freezing
5. Acid rain
6. Wind
7. Water
A. Chemical
Weathering
B. Mechanical
Weathering
C. Both types
of
weathering
What type of weathering???
What type of weathering???
What type of weathering???
What type of weathering???
What type of weathering???
What type of weathering???
What type of weathering???
8. Erosion
• When rock and soil are moved from one
place to another by natural forces, this
is called Erosion.
• The agents of Erosion are
– Water (rain water runoff, streams, rivers,
groundwater, and waves)
– Ice (Glaciers)
– Wind
– Gravity ( landslides,
mudslides, avalanches etc.)
9. Sediment
• The material moved
by erosion is
sediment.
• Sediment is small,
solid particles of
rocks or organisms.
10. Deposition
• When the sediment being carried is
dropped (or deposited) in a new area,
it is called deposition.
• Depositions can create new landforms
like beaches and sand dunes.
CHECK-UP
• Choose
one of the
following
for each
example:
A.) Erosion
B.)Deposition
1. A river carrying sand
2. Dropping sediment in a
new location
3. A glacier picking up a rock
in it’s path.
4. A beach is formed.
5. How a sand dune is created
6. How sediment is moved
7. Sand being carried by the
wind in a sandstorm.