1. Plate Tectonics and Landforms

2. Plate tectonics describes plate motion and the effects of the motion
Plate tectonics describes plate motion and the effects of the motion. Plate tectonics says that Earth’s outer shell is made of about 20 plates. The plates are rigid and in constant motion relative to one another.

4. The largest plates consist of two different kinds of crust; oceanic and continental. Many of the smaller plates contain only oceanic crust.

5. Continental crust is thicker and less dense than oceanic crust
Continental crust is thicker and less dense than oceanic crust. Continental crust is composed mostly of the igneous rock granite, while ocean crust is mostly the igneous rock basalt.

6. The plates sit on the hot asthenosphere
The plates sit on the hot asthenosphere. While the rock in the asthenosphere is solid, it is less rigid than the plates, and therefore moves. The movement within the asthenosphere is caused by heat from the core of the earth.

7. https://youtu.be/ryrXAGY1dmE
The heat rises slowly through the earth creating convection cells within the asthenopsphere.
The material carried by convection cells in the asthenosphere drag the plates along.

8. By destroying and creating plate material, plate tectonics constantly recycles Earth’s materials.

9. Each plate moves as a distinct unit
Each plate moves as a distinct unit. The borders between plates are called plate boundaries.

10. The interaction between plates results in different effects on the earth’s surface. One of the effects of plate motion is the Ring of Fire. The Ring of Fire is an area of volcanoes that form a ring around the Pacific Plate.

11. Convergent– plates move toward one another
Ocean / Continental
Continental / Continental

12. https://youtu.be/NbDqJy28hBw
Oceanic/Continental: plates are colliding and ocean crust is subducted, or pulled into the mantle, and melted. This process forms deep ocean trenches and destroys plate material in what we call the subduction zone.
Harry Hess predicted that this was happening.

13. Tight lines of volcanoes create island and volcanic arcs
Landforms:
Deep Ocean Trenches
Tight lines of volcanoes create island and volcanic arcs
Places:
Cascade Mountain Range, Oregon and Washington, Mt. St Helen
Mariana Trench

14. Continental / Continental Crust
Plates crash into one another
No volcanic activity
Landforms
Mountain Ranges
Places
Himalaya Mountains, India

15. Divergent - plates move away from one another (seafloor spreading)
New crust material is created
Shallow earthquakes along the plate boundary
Ocean/ocean crust

16. Landforms
Creates Mid-ocean Ridge
Rift Valleys
Places
Mid-Atlantic Ridge, Atlantic Ocean

17. Transform—plates grind past one another
Shallow Earthquakes
Some volcanoes, but spread out
Mostly Ocean Crust
Some Continental

18. Landforms
Faults (breaks in rock)
Places
San Andreas Fault, California

19. Plate Tectonic Lab next week