Plate Tectonics and Continental Drift

Eric AngatTeacher

Continental drift and Plate tectonics theory

1.How is Earth like a jigsaw puzzle? 2.How is Earth affected by the slow

movement of the tectonic plates? 3.How are mountain formed? 4.What kind of plate boundaries causes

earthquakes?

Continental drift and Plate tectonics theory

Videos: http://www.youtube.com/watch?v=ELd3ebldSTs

Continental drift and Plate tectonics theory

1.How is Earth like a jigsaw puzzle?

2.How is Earth affected by the slow movement of the tectonic plates?

Earth’s crust is broken into many pieces like a jigsaw puzzle.

The slow movement of tectonic plates causes earthquakes, subduction, form mountains, volcanoes, rift valley, and trenches.

Continental drift and Plate tectonics theory

3.How are mountain formed?

4.What kinds of plate boundaries cause earthquakes?

Mountains form when tectonic plates collide and uplift happen.

Convergent boundary along the Pacific Ring of Fire, Transform boundary, earthquake happen along the fault line, and divergent boundary vertically across the Atlantic ocean.

Sea Floor Spreading

5. Who is Alfred Wegener?6. Who is Harry Hess?7. What is happening to the Atlantic Ocean?8. Where are the newest oceanic crust found?9. Why is Earth not getting bigger in spite of sea floor is spreading?10. What happens to the crust subducted into the mantle?

Sea Floor Spreading

Videos: http://www.youtube.com/watch?v=oXYAdzmwQsc

Sea Floor Spreading

5. Who is Alfred Wegener?

6. Who is Harry Hess?

Alfred Wegener proposed the theory of continental drift but he could not explain how continents move.

Harry Hess a geologist and navy commander who proposed that continents move because of sea floor spreading.

Sea Floor spreading happening in the Atlantic Ocean

Magma rises forming new crust.

Atlantic Ocean widening on both sides

Sea Floor Spreading

7. What is happening to the Atlantic Ocean?

8.Where are the newer oceanic crust found?

The Atlantic Ocean is widening because of Sea Floor Spreading.

Newest oceanic crust are found nearest the mid-ocean ridges.

Sea floor spreading is making the Atlantic Ocean wider.

But the Earth is not growing

bigger! Why?Because Pacific Ocean crust is subducted into the mantle.

Subduction recycles Earth’s crust into

new rocks.

Most earthquakes happen around the Pacific Ocean.

A lot of volcanoes!

Sea Floor Spreading

9. Why is Earth not getting bigger when the sea floor is spreading?

10. What happens to the crust subducted into the mantle?

Because on the other side of Earth there is subduction.

The crust gets melted and recycled into new rocks, volcanoes form adjacent to subduction zone.