Chapter 2 - Plate Tectonics
Which of the following statements about coral reefs and seamounts is most accurate? (A) Seamounts at the ocean surface grow towards coral reefs over time. (B) Coral reefs at the ocean surface grow away from seamounts over time. (C) Seamounts at the ocean surface grow away from coral reefs over time. (D) Coral reefs at the ocean surface grow towards seamounts over time.
(B)
Transform boundaries are classified under what type of fault?
Strike-slip.
What is the relationship between the crust and the lithosphere?
The crust is part of the lithosphere.
What would happen to Earth if ocean floor were created at divergent boundaries at a faster rate than it is destroyed at convergent boundaries?
Earth would increase in volume.
Which of the following statements about Earth's magnetic field is most accurate?
Earth's magnetic field switches polarity at irregular time intervals.
How often does the Earth's magnetic field switch polarity?
Every 100,000 to several million years.
Where do coral reefs exist with sea mounts?
In tropical latitudes.
Why are volcanoes not found at transform boundaries?
Transform boundaries do not cause changes to the pressure, temperature, or composition of the mantle.
Why do coral reefs at the ocean surface grow away from seamounts over time?
Seamounts subside as tectonic plates move. Coral reefs grow away from the seamount in order to stay near the sunlight.
What is a tablemount?
A seamount that grew above sea level, experienced wave erosion, and is now inactive.
Complete this statement: Divergence is to moving away as convergence is to _______.
moving toward
What is the difference between a barrier reef and an atoll?
Barrier reefs surround an inactive volcano emerging above sea level, while atolls surround the previous location of a submerged volcano.
Why do hotspots result in chains of volcanoes instead of a single volcanic peak?
Because the plate is moving over the hotspot
In general, where do both earthquakes and volcanic eruptions occur?
At divergent and convergent plate boundaries.
Where do mantle plumes originate?
Deep in the mantle, near the core.
Do fracture zones near transform boundaries play a role in plate motion?
No; fracture zones play no role in plate motion.
Which geologic features are associated with convergent boundaries?
Ocean trenches and volcanoes.
Where would you expect to see alternating bands of rock with different magnetic polarities?
On both sides of the mid-ocean ridge.
In general, where do volcanoes form in subduction zones?
On the overriding plate, away form the convergent boundary.
How are normal polarity and reverse polarity of Earth's magnetic field different?
A compass points toward the North Pole during normal polarity and to the South Pole during reverse polarity.
Which of the following features are found at an oceanic-continental convergent plate boundary?
A continental arc, mountains, and trench.
In general, what is our best evidence that the orientation of Earth's magnetic field has changed over time?
A record of Earth's magnetic field is recorded in oceanic rocks, which show a clear pattern of changes in Earth's magnetic polarity.
What is a volcanic arc?
A row of volcanoes that forms on the overriding plate near a subduction zone.
Where is the youngest ocean floor found?
Along the crest of mid-ocean ridges
What is a seamount?
An active volcano that occurs along the crest of the mid-ocean ridge.
The East African rift is a divergent plate boundary that is splitting the continent of Africa into two pieces. What will eventually form around this divergent boundary?
An ocean.
Which of the following mountain ranges are examples of continental arcs?
Andes and Cascades.
Which type of plate boundary is most closely associated with the formation of new ocean floor?
Divergent.
Which is the correct order of coral reef development near seamounts?
Fringing reef, barrier reef, atoll.
Which geographic example below was created by a hotspot?
Hawaii.
Which geographic examples below result from ocean-ocean convergence?
Marianas Trench, Aleutian Islands, Japan.
Which geologic features are associated with divergent boundaries?
Mid-ocean ridges and continental rift valleys.
What forms at divergent plate boundaries?
New oceanic lithosphere.
What happens when an oceanic plate converges with a continental plate?
The oceanic plate is subducted.
What happens when an oceanic plate meets another oceanic plate?
The older, colder oceanic plate is subducted.
Which volcano would you expect to be active?
The one closest to the star.
Which volcano would you expect to be the oldest?
The one furthest away from the star.
How do plates move at divergent plate boundaries?
The plates move apart.
How do plates move at transform plate boundaries?
The plates move side by side.
How do plates move at convergent plate boundaries?
The plates move together.
What happens when a continental plate meets another continental plate?
The two plates are forced upward, and a large mountain range is formed.
What role do transform boundaries play?
Transform boundaries connect other segments of plate boundaries.
What is the relationship between transform boundaries and mid-ocean ridges?
Transform boundaries connect segments of mid-ocean ridges.
Plates move apart at __________ boundaries, move together at __________ boundaries, and move side by side at __________ boundaries.
divergent/convergent/transform