1. Weathering, Erosion, & Deposition
What are the effects of weathering, erosion, and deposition on the environment in Texas Eco-regions?

2. The Cycle of the Changing Earth’s Surface
Weathering, erosion, and deposition act together in a
cycle that wears down and builds up Earth’s surface
Weathering-wears down the Earth’s surface
Erosion - moves the Earth’s surface (acts as a bridge between the weathering and deposition)
Deposition - builds up the earth’s surface

3. Please draw this in your notes
Weathering
Erosion
Deposition

4. Weathering The breaking down and/or wearing away of earth
materials (rocks) into smaller pieces
Must occur before erosion can happen
No movement is involved
Sediments- naturally-occurring
material that is broken down by
processes of weathering;
small/tiny pieces of rock

5. Palo Duro Canyon in the High Plains Eco-Region
Physical Weathering
Physical/Mechanical weathering …
the breaking down of rocks into smaller pieces (wind, flowing water, ice, gravity, animals/plants, temperature changes)
Physical Weathering -- The steep walls here were carved out by moving water
Palo Duro Canyon in the High Plains Eco-Region

6. Enchanted Rock in the Llano Uplift Eco-region
Physical Weathering
Enchanted Rock in the Llano Uplift Eco-region
Exfoliation-warming and cooling
of rocks over time causes rocks
to peel into sheets

7. This cave was formed by slightly acidic water dissolving the limestone
Chemical Weathering
Chemical weathering occurs when chemical reactions dissolve the minerals in rocks or changes them into different minerals (rusting, acid breakdown, etc)
This cave was formed by slightly acidic water dissolving the limestone

8. Chemical Weathering
Natural Bridge Caverns in Texas

9. Let’s compare Please draw a Venn diagram and compare
chemical and physical weathering.
How are they similar/different?

10. Erosion
The movement of weathered earth materials by moving water, wind, gravity or ice
Example: waves causing beach erosion (shoreline of Texas is disappearing) running water
Example: sand storm wind
Example: rain causing a mudslide running water and gravity
Example: landslide gravity
Example: rain carrying soil and gravel down a driveway running water and gravity

11. Galveston Texas before/after Hurricane Ike
Erosion
Galveston Texas before/after Hurricane Ike

12. Erosion
A gorge is a ravine with nearly vertical walls. This gorge was cut when heavy rains pushed a flood over Canyon Lake Dam in central Texas in 2002.

13. Erosion
The Bernard Glacier in Alaska's Saint Elias Mountains looks like a huge alpine highway.
Glaciers are slow but highly effective shapers of the land, essentially carrying away anything in their path—from soil and rocks to hills and even the sides of mountains

14. Why care about erosion? Human activities such as construction increase
the rate of erosion 200, even 2,000 times that
amount. When we remove vegetation or other
objects that hold soil in place, we expose it to the
action of wind/water and increase its chances of eroding.
The loss of soil from a construction site results in loss of topsoil, minerals and nutrients, and it causes ugly cuts and gullies in the landscape. Surface runoff and the materials it carries with it clog
our culverts, flood channels and streams. Sometimes it destroys
wildlife and damages recreational areas such as lakes and reservoirs.

15. Bare Slopes vs. Vegetation Stabilized Slopes
How do weathering, erosion and depostion impact
each side of the “hill”?

16. Bare Slopes vs. Vegetation Stabilized Slopes
Mudslide danger
Loss of topsoil
Clogged storm drains
Flooding problems
Expensive clean up
Eroded or buried
house foundations

17. Bare Slopes vs. Vegetation Stabilized Slopes
Soil in place
Less clean up
Minimum erosion
Protection
for house
foundations
Mudslide danger
Loss of topsoil
Clogged storm drains
Flooding problems
Expensive clean up
Eroded or buried
house foundations

18. Landslides
Landslides -- a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments.

19. Deposition The process of eroded earth materials
(sediments) being deposited in a new location
Example: delta -- where sediment is deposited where
a river flows into an ocean or lake builds up a landform

20. Deposition
Desert winds sculpted these gentle swirls out of the limestone hills in Black Gap Wildlife Management Area, Texas. This remote, 100,000-acre area in West Texas contains some of
the lowest, driest, and
hottest areas in the
Chihuahuan Desert

21. Deposition Deposition area from the Rio Grande River
The Red River carries sediments, and drops some along the way