Plate Tectonics
What was Pangaea?
a supercontinent that began to break apart about 200 million years ago
Where are tectonic plates located?
at Earth's surface
Plates move apart at __________ boundaries, move together at __________ boundaries, and move side-by-side at __________ boundaries.
divergent/convergent/transform
Which geologic features are associated with divergent boundaries?
mid-ocean ridges and continental rift valleys
Which geologic features are associated with convergent boundaries?
ocean trenches and volcanoes
What are two differences between oceanic crust and continental crust?
The continental crust is thicker and less dense than oceanic crust.
Complete this statement: Divergence is to moving away as convergence is to _______.
moving toward
Which plate boundary is NOT associated with volcanic eruptions?
transform
Hawaii is the oldest island of the Hawaiian Island chain.
False
How was the fossil record of ancient life used to support Wegener's hypothesis about Pangaea?
Fossils of identical organisms were found on several continents, indicating the continents were once joined.
Which of the following is evidence of continental drift?
Glossopteris fossils found on Antarctica and Australia, coal deposits in North America, matching rock units found in Brazil and Africa
What is the relationship between the mantle and the lithosphere?
Some of the mantle is contained within a smaller layer called the lithosphere.
What was the first evidence that led early researchers to suspect that Earth's continents were once connected?
The coastlines of the continents, especially South America and Africa, fit together like a jigsaw puzzle.
What is the relationship between the crust and lithosphere?
The crust is part of the lithosphere.
At a divergent boundary, what is the relative motion of the plates on each side of the boundary?
The plates move away from each other.
The oldest rocks on the seafloor are much younger than the oldest rocks on the continents.
True
What is the relationship between continent edges and plate boundaries?
Very few plate boundaries follow the edges of continents.
What is the relationship between the mantle and the asthenosphere?
All of the asthenosphere is contained within a larger layer called the mantle.
What is the relationship between the crust and the lithosphere?
All of the crust is contained within a larger layer called the lithosphere.
Which part of the Earth is responsible for generating the planet's magnetic field?
Core
Which tectonic boundary results when two tectonic plates pull apart from each other?
Divergent boundaries
In studies of rock obtained from ocean basins all over Earth, the oldest ages obtained are approximately 200 million years before the present. Why have no older oceanic rocks been discovered?
Due to tectonic activity, rocks on the ocean floor are continually recycled.
Since the breakup of Pangaea approximately 165 million years ago, a new supercontinent cycle has begun with the collision of which of the following continents?
India and Asia
Which of the following statements about divergent boundaries is true?
New ocean crust is created at a divergent boundary.
Which of the following is a feature of a divergent plate boundary?
an oceanic ridge, a rift valley
Which type of plate boundary is most closely associated with uplifting continental regions and mountain building?
convergent boundaries
Which type of plate boundary is most closely associated with the formation of new ocean floor?
divergent
What are the three types of plate boundaries?
divergent, convergent, and transform
