1. Earth’s Forces

2. What is Plate Tectonics?
Movement of large plates (crust) above magma in the mantle
What proof is there?
Fossils, plants and animals along coastlines of separated continents

3. What is the theory of Continental Drift?
1912 theory by Alfred Wegener
Earth once had a supercontinent (all connected)
Called “Pangea”
What is the theory of Continental Drift?

4. What type of movements are there?
Divergent
Convergent: Subduction
Convergent: Collision
Transform

5. Sub-Duction Zone
Two tectonic plates meet and one bends and slides under the other.
Continental and oceanic plates

6. Convergent: Collision
Continent-continent
Collide without subducting
India slammed into Asia; ex: Himalayas

7. Divergent Boundaries
Oceanic plates move apart and create cracks in ocean floor
Magma rises from mantle through cracks; forms new crust of igneous rock.
Example: Sea Floor Spreading

8. Transform Boundary Two plates move horizontally
Friction in rocks causes plates to lock.
Rocks fracture and the sudden release of energy is what we feel during earthquake.
Ex: San Andreas

9. Volcanoes What is the Ring of Fire?
Most volcanoes located around the rim of the Pacific Ocean

11. How does erosion shape our land?
Bellringer #6
How does erosion shape our land?

12. What is Weathering? Types of Weathering are…
Mechanical – When rocks and other minerals are broken into smaller pieces.
Chemical – When minerals are changed completely when they mix with water and air. Like metal changing to rust.

13. What is Wind Erosion? Loess is wind-blown silt, sand, and clay.
Can form sand dunes 100’s of feet deep!

14. What is Water Erosion?
Precipitation
Mudslides
Avalanche

15. What is Glacial Erosion?
Glaciation – changes in a landform made from a slowly moving sheet of ice (glacier)
Moraines – rocks left behind after a glacier moves
Creates new valleys, hills, or ridges

16. ASSIGNMENT What is this force?
EROSION
WEATHERING
What is this force?
How does it change the physical surface?
What are the different ways this external force can occur?
What type of landforms does it affect?
What are some examples?