Dynamic Earth Notes and Study Guide



Dynamic Earth Study Guide

1. What is the theory of continental drift?

Continents were once close together but drifted apart over time

2. Who first came up with the theory of continental drift?

Alfred Wegener

3. What evidence did he use to support his theory?

Fossils of the same organisms were found different continents. Matching rock formations on south America and Africa. The continents themselves seem to fit together like puzzle pieces.

4. What is the name of the supercontinent that existed near the end of Paleozoic?

Pangaea

5. What is sea-floor spreading? How does it relate to the theory of continental drift?

Sea floor spreading occurs when hot less dense material from below the Earth’s surface rises to the crust and flows sideways carrying the ocean floor away with it. Sea floor spreading is the force that drives continental drift (it pushes the plates)

6. What are tectonic plates? Are tectonic plates the same thing as continents? Explain.

Tectonic plates are huge chunks that the Earth’s crust is broken into. They are not the same thing as continents. Continents sit on top of tectonic plates

7. Draw a diagram of the layers of the Earth and label it. Include the inner core, outer core, mesosphere (lower mantle), aesthenosphere, lithosphere, crust

8. Draw a diagram for each of the three types of plate boundaries. Explain how the plates move at each type of boundary.

Convergent Boundary Divergent Boundary

Plates move together Plates move apart Transform Boundary

Plates slide past each other

9. What are convection currents? How do they help explain how the plates move? Use a little diagram to illustrate your answer.

Hot liquids (including melted rock) are less dense than cold and will rise. This motion is convection currents and is what causes the plates to move that are riding on the surface of all of this.

The Earth’s crust is composed of continental plates that are in constant motion because of the convection currents in the Earth’s mantle and outer core. It is this movement that causes earthquakes and volcanoes.

10. What types of landforms are created at divergent plate boundaries?

Divergent boundaries cause mid oceanic ridges. Some other common characteristics of divergent boundaries are high heat flow, mild volcanic activity, and shallow earthquakes

11. Where/how do mountains and volcanoes form?

Two plates can press against each other until the land is lifted and folded over itself. One plate can push on top of another one. As one plate slides downward into the earth, it begins to melt. The melted rock rushes upward along cracks and weak spots, bursting out as fiery volcanoes

12. What is a subduction zone? At what type of boundary are subduction zones formed? What often forms as a result of a subduction zone?

A subduction zone is an area on Earth where two tectonic plates meet and move towards one another, with one sliding underneath the other and moving down into the mantle. Where the plate is subducted a trench forms. The melted plate material can create pressure and often causes volcanoes.

13. What do strike-slip (transform) boundaries often cause?

Earthquakes

14. What is a fault?

A fault is a crack in the earth formed because of the movement of tectonic plates

15. What type of waves cause earthquakes? How are earthquakes measured?

Seismic waves cause earthquakes. Earthquakes are measured with the Richter scale.

16. What are tsunamis? (How are they formed?)

Giant waves formed when earthquakes or volcanoes occur underwater

What is the ring of fire?

A ring of volcanic activity along the boundary of the North Pacific Ocean.

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