Name: __________________________________________ Class:_____________
Hour:____________
Essays on Plate Tectonics
Direction: Use complete sentences to answer the essay questions below. Each essay should be 67 sentences long. You may also include a diagram with your essay for detailed explanation.
1. Explain the process of subduction.
2. What is the major evidence that sea-floor spreading creates new lithosphere? Explain
your answer.
3. Tectonic plates forming a transform boundary may move only a few centimeters each
year. Can even this small movement affect people and communities living near a
transform boundary? Explain your answer.
Answer Key Essays on Plate Tectonics
1. Explain the process of subduction.
A denser oceanic plate is forced beneath a less dense oceanic or continental plate at a convergent
boundary. Gravity pulls the oceanic plate into the asthenosphere, which causes melting.
2. What is the major evidence that sea-floor spreading creates new lithosphere? Explain
your answer.
Answers will vary. Sample answer: Molten rock at mid-ocean ridges has magnetized minerals
that align with Earth’s magnetic field. When the Earth’s magnetic field reverses, the magnetized
minerals align in the opposite direction. The record of magnetic reversals is carried away from
each side of the spreading center of a mid-ocean ridge, showing that the molten rock is creating
new lithosphere.
3. Tectonic plates forming a transform boundary may move only a few centimeters each
year. Can even this small movement affect people and communities living near a
transform boundary? Explain your answer.
Answers will vary. Sample answer: When tectonic plates slide past each other, the movement
may cause earthquakes, which might injure people or damage property in a community.
Name: __________________________________________ Class:_____________ Hour:____________
Direction: Use the following terms to complete the concept map below:
South America
Pangaea
North America
Laurasia
Gondwana
a. Pangaea; b. Gondwana; c. Laurasia; d. North America; e. South America
Name: __________________________________________ Class:_____________ Hour:____________
Plate Tectonics Short Answer
Direction: Use complete sentences to answer the short answers below. Each short answer should
be 3-4 sentences long. You may also include a diagram with your essay for detailed explanation.
1. Explain how folded mountain ranges form.
2. Describe the role of the asthenosphere in the movement of tectonic plates.
3. How does the position of a hanging wall relative to the footwall give evidence of the stress placed
on a rock layer?
4. How do fossils help prove that the continents move?
Answer Key Plate Tectonics Short Answer
1. Explain how folded mountain ranges form.
Folded mountain ranges form when two tectonic plates with continental crust collide. The crust is forced
upward at the point of collision, which forms mountains over a long period of time.
2. Describe the role of the asthenosphere in the movement of tectonic plates.
The asthenosphere is a layer made of solid rock that flows very slowly. The tectonic plates float, or move
very slowly on top of the asthenosphere.
3. How does the position of a hanging wall relative to the footwall give evidence of the stress placed
on a rock layer?
When rocks are pulled apart by tension, hanging walls tend to slip below the footwall. When rocks are
pushed together by compression, hanging walls tend to push above the footwall.
4. How do fossils help prove that the continents move?
Fossils of the same plant and animal species have been found on continents on different sides of the
Atlantic Ocean.