How does weathering, erosion, & deposition
act in a cycle to change the Earth’s surface?
-breaks down the Earth
Weathering
Deposition
– drops off, to build the Earth
Erosion
- moves the Earth
What is Weathering?

The breaking down of rocks into smaller pieces
Must occur before erosion can
happen
 No movement is involved
 Two types: Mechanical & Chemical
 Sediments- small/tiny pieces of
weathered down rock.

What is Physical Weathering?
 Physical/Mechanical
weathering …
the breaking down of rocks into smaller pieces with out
changing the material
Physical Weathering -- The steep walls here
were carved out by moving water
Palo Duro Canyon in the High
Plains Eco-Region
Physical
Weathering
1. Animal burrowing
2. Plant Roots
3. Ice Wedging
4. Abrasion
Enchanted Rock in the Llano
Uplift Eco-region
5. Exfoliation-warming and cooling
of rocks over time causes rocks
to peel into sheets
What is Chemical Weathering?
 Chemical
weathering …
dissolving and changing the minerals in rocks into new ones.
1. Oxidation-Rusting
2. Plant Acids
3. This cave was formed by
slightly acidic water
dissolving the limestone
(carbonic acids)
What is Erosion?

The movement of weathered earth materials
by moving water, wind, gravity or ice (glaciers)
Example
Cause of Erosion
Waves eroding the beach and East
TX shoreline
Water
Desert Sandstorm in West TX from
drought
Wind
Rain causing Mudslide in the
Rolling Hills of Central TX
Landslide on sides of Plateaus of
Central TX
Rain carrying soil down a driveway
Water & Gravity
Gravity
Water & Gravity
How does removing plants effect the erosion on the
left side of the hill?
Draw and answer the question
What is Deposition?
1.
2.
3.
4.


Delta
Mountains
Sand Dunes
Plateau
When eroded sediments are deposited in a new location
Example: delta -- where sediment is deposited where
a river flows into an ocean or lake builds up a landform
Before
After