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PLATE TECTONICS Student Progress Monitoring Sheet Answer Key
1. Illustrate and label the layers of the earth including the crust, mantle, outer core and inner core.
Crust – Thin solid outer layer of the Earth; includes the lithosphere.
Mantle – Thickest layer of the Earth made of semi-solid soft rock; includes the asthenosphere & mesoshpere
Outer Core – Liquid rock layer made of mostly iron and nickel
Inner Core – Solid rock center of the Earth made of mostly iron and nickel
2. Describe and explain the Earth’s lithosphere.
The lithosphere is the outer layer of the Earth which includes the crust and is solid rock broken up into Earth’s tectonic plates.
3. Describe and explain the Earth’s asthenosphere?
The asthenosphere is the semi-solid upper part of the mantle underneath the lithosphere that slowly moves because of convection currents
created by the heat from Earth’s inner and outer core.
4. What are Earth’s tectonic plates?
The tectonic plates are the broken slabs of Earth’s lithosphere that slowly move because of plate tectonics
5. What was the early hypothesis of Continental Drift? Who first proposed this hypothesis?
Continental Drift was a hypothesis proposed by Alfred Wegener in the early 1900’s. He hypothesized that the continents were once connected as
a super continent he called Pangaea over 200 million years ago. Over time the continents have slowly moved to their current locations and will
continue to move over time.
6. What evidence was discovered that supports Continental Drift?
Shapes of the continents fit together
Similar fossil records on different continents
Similar rocks and minerals on different continents
Similar rock formations on different continents
Climatic evidence on different continents
7. What is the Theory of Plate Tectonics?
States that Earth’s crust is broken up into large slabs of rock called tectonic plates that slowly move over time.
8. What evidence supports the Theory of Plate Tectonics?
All the evidence that supports continental drift
Sea Floor Spreading and subduction
Sea floor magnetic reversal patterns and age of rock on the sea floor
Locations of earthquakes and volcanoes at plate boundaries
9. What is seafloor spreading? Where does it take place?
Sea Floor Spreading is the spreading of the sea floor at mid-ocean ridges caused by magma coming up through a crack in Earth’s lithosphere at
divergent boundaries caused by convection currents in Earth’s asthenosphere.
10. How does seafloor spreading support the Theory of Plate Tectonics?
The age of the rock at the center of mid-ocean ridges is the youngest. The age of rock gets older as you move away from the ridge. Patterns of
magnetic reversals in the rock on the sea floor also show that new rock continually forms at mid-ocean ridges.
11. What force causes tectonic plates to move and where does it occur?
Convection currents of heated rock in Earth’s mantle is the force that causes tectonic plates to move.
12. Illustrate and describe the plate movement at convergent boundaries.
1. Tectonic Plates collide at convergent boundaries
13. What is the difference between oceanic and continental crust? Which is denser? How does the density of the crust affect plate movement?
Oceanic crust is crust that makes up the sea floor. Continental crust is crust that makes up land. Oceanic crust is denser and thinner than
continental crust and therefore subducts under the continental crust when they collide at convergent boundaries.
14. What crustal features form when oceanic crust collides with continental crust at a convergent boundary?
The Oceanic Crust subducts under the continental crust forming a subduction zone.
Deep Sea Trenches form in the ocean and volcanoes form on land when oceanic crust collides with continental crust.
15. What crustal features form when oceanic crust collides with oceanic crust at a convergent boundary?
The older oceanic crust subducts und the newer oceanic crust forming a subduction zone.
Deep Sea Trenches and Volcanic Island Arcs form in the oceans when oceanic crusts collide.
16. What crustal features form when continental crust collides with continental crust at a convergent boundary?
When continental crusts collide the rock buckles upward forming Mountains on land.
17. What are subduction zones? What causes this to occur?
Subduction zones are formed when one tectonic plate is pulled under another tectonic plate at a convergent boundary and recycled back into the
mantle forming deep ocean trenches.
1. Illustrate and describe the plate movement at divergent boundaries.
18. Tectonic Plates move apart (divide) at divergent boundaries.
19. What crustal features form at divergent boundaries? Mid-Ocean Ridges and Rift Valleys on land
20. What are mid-ocean ridges? What occurs at mid-ocean ridges? What geologic feature are mid-ocean ridges?
Mid-ocean ridges are chains of volcanic mountain ranges at the bottom of the oceans where sea floor spreading occurs.
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21. Illustrate and explain the plate movement at transform boundaries.
Tectonic Plates slide past each other at transform boundaries.
22.What crustal features form at transform boundaries? Fault lines
23.How has the Earth’s surface changed as a result of plate tectonics? The continents continually move. The Atlantic ocean is getting bigger.
The Pacific ocean is getting smaller. New sea floor is continually formed at mid-ocean ridges and crust is destroyed at subduction zones in
trenches. Mountains and volcanoes form and get bigger.