1. Weathering, Erosion, and Plate Tectonics
The creation of Earth’s Face

2. Questions
What forces and phenomena create the different features of the earth?
What are tectonic plates?
What are the three major Types of Plate Boundaries?
What are the two external processes that change the earth’s surface?
What are the different types of Weathering and Erosion?

3. Forces that change the Earth’s Surface
There are two major geological processes that create features on the earth:
Faulting and Plate Tectonics
Weathering and Erosion
They both take a long time to change the earth.
Remember, nothing drastic on earth happens at human speeds.

4. Plate Tectonics
Huge volumes of heated and molten rock moving around the earth’s interior form massive solid plates that move extremely slowly across the earth’s surface.
Tectonic plates: huge rigid plates that are moved with convection cells or currents by floating on magma or molten rock.

5. The Earth’s Major Tectonic Plates
Figure 15-4

6. Plate Movement Tectonic Plates move in 1 on four ways.
Spreading, or moving apart
Subduction, or diving under another plate
Collision, or crashing into one another
Sliding past each other in a shearing motion

7. The Earth’s Major Tectonic Plates
The extremely slow movements of these plates cause them to grind into one another at divergent plate boundaries, move apart at convergent plate boundaries and slide past at transform plate boundaries.
Figure 15-4

8. Figure 15.4
Natural capital: the earth’s major tectonic plates. The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart from one another at divergent plate boundaries, and slide past one another at transform plate boundaries. QUESTION: What plate are you floating on?
Fig. 15-4, p. 338

9. INDIA-AUSTRALIAN PLATE
EURASIAN PLATE
NORTH AMERICAN PLATE
ANATOLIAN PLATE
JUAN DE FUCA PLATE
CARIBBEAN PLATE
CHINA SUBPLATE
ARABIAN PLATE
AFRICAN PLATE
PHILIPPINE PLATE
PACIFIC PLATE
SOUTH AMERICAN PLATE
NAZCA PLATE
INDIA-AUSTRALIAN PLATE
SOMALIAN SUBPLATE
Figure 15.4
Natural capital: the earth’s major tectonic plates. The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart from one another at divergent plate boundaries, and slide past one another at transform plate boundaries. QUESTION: What plate are you floating on?
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Fig. 15-4a, p. 338

10. GEOLOGIC PROCESSES
The San Andreas Fault is an example of a transform fault.
A fault Line is created when rocks meet and lack flexibility. They crack under pressure and the fracture is called a FAULT.
Figure 15-5

11. Results of Movement Earthquakes are a result of plate movement.
The Richter Scale is used to measure the intensity of an earthquake.
Tsunamis can result from earthquakes originating in the ocean.
Volcanoes are often located along the boundaries of tectonic plates.
Magma, gases, ash, and dust explode out of these vents in the earth’s surface.
Ring of Fire is located along the rim of the Pacific Ocean and contains most volcanoes.

13. Wearing Down and Building Up the Earth’s Surface
Weathering is an external process that wears the earth’s surface down.
Figure 15-6

14. Weathering Three types of weathering: Physical Chemical Biological
Big Rock becomes Small Rock due to wind, rain, and frost wedging.
Frost wedging occurs when water freezes in between the pores of large sedimentary rocks.
Chemical
When a chemical reaction degrades or decomposes a rock.
More common with rocks containing carbon and oxygen, like limestone.
Biological
Conversion of Rock and Minerals into smaller particles due to living thing.
Lichens, Tree Roots, Earthworms.

15. Parent material (rock)
Biological weathering (tree roots and lichens)
Chemical weathering (water, acids, and gases)
Physical weathering (wind, rain, thermal expansion and contraction, water freezing)
Figure 15.6
Natural capital: physical, chemical, and biological processes can weather or convert rock into smaller fragments and particles. It is the first step in soil formation.
Particles of parent material
Fig. 15-6, p. 340

16. Erosion
Erosion is another major external factor that changes the surface of the earth.
Erosion is different from weathering because erosion deposits materials from one place to another.
Four major examples of erosion:
Glacial Movement and Melt
Mass Wasting
Water Erosion
Wind Erosion

17. Glacial Movement and Mass Wasting
The Movement of Glaciers grind away mountainsides and form basins to capture melted ice water
The Great Lakes were formed using this method.
Mass Wasting
When Rock and soil masses become detached from underlying material and move downhill under the influence of gravity.
Rockslides, Mudslides, and Landslides
Clearing of Trees and other vegetation increase Mass Wasting Occurrences.

18. Water and Wind Erosion Water Erosion Wind Erosion
Water picks up material and moves it down stream.
Waves can also reduce or increase beaches.
Wind Erosion
Wind transports and deposits sediments.
Wind speeds must reach a minimum of 11 miles per hour before sediment can be moved.