Chapter 9 Earth Science Test-Exam Review
What results when divergence occurs between two oceanic plates?
seafloor spreading
What mechanism of plate motion is illustrated in Figure 9-2?
slab-pull
What process is illustrated by the area labeled G in figure 9-1?
subduction
Deep ocean trenches are associated with
subduction zones
A(n) __________ occurs where two plates grind pass each other without creating or destroying lithosphere.
transform fault boundary
What kind of plate boundary occurs where two plates grind past each other without destroying or producing lithosphere?
transform fault boundary
What feature is labeled B in figure 9-1?
trench
A chain of small volcanic islands that forms when two oceanic plates converge, one descending beneath the other, is called a(n) __________.
volcanic island arc
What feature is labeled A in Figure 9-2?
volcanic island arc
What type of boundary occurs where two plates move together, causing one plate to descend into the mantle beneath the other plate?
convergent boundary
The Himalayas in South Asia are an example of what type of plate boundary?
convergent continental-continental boundary
At a(n) ___________ boundary, oceanic lithosphere plunges beneath overriding continental plate.
convergent oceanic-continental
Continental volcanic arcs are associated with what type of plate boundary?
convergent oceanic-continental boundary
What type of plate boundary is illustrated in figure 9-1
convergent oceanic-continental boundary
Volcanic island arcs are associated with what type of plate boundary?
convergent oceanic-oceanic boundary
What type of plate boundary is illustrated in Figure 9-2?
convergent oceanic-oceanic boundary
One kind of evidence that supports Wegener's hypothesis is that
fossils of the same organism have been found on different continents
Typical rates of seafloor spreading are approx.
5 centimeters per year
What was the main reason Wegener's continental drift hypothesis was rejected?
He could not provide a mechanism for the movement of continents
According to Figure 9-2, if the plate labeled H descends into Earth's interior, what will occur between the positions labeled Y and X?
Earthquake foci will be shallower at Y and increase in depth at X
In the continental drift hypothesis, a super continent called ________ was proposed.
Pangaea
The geographic distribution of the swimming reptile Mesosaurus lived
South America and Africa were once joined
The Hawaiian Islands were formed when the Pacific Plate moved over
a hot spot
What forms when one oceanic plate is forced beneath another plate?
a subduction zone
The age of the rocks in the ocean basins were determined by
age decreases
How does the age of seafloor sediments change with increasing distance from the ocean ridge?
age increases
The thermal convection that drives plate motion is caused by
an unequal distribution of heat
What hypothesis states that the continents were once joined to form a single supercontinent?
continental drift
Why are subduction zones not commonly found at convergent continental-continental boundaries?
continental lithosphere is too buoyant to be forced down into the mantle
The type of plate boundary where plates move apart, resulting in upwelling of material from the mantle to create new seafloor, is referred to as a(n) _______ plate boundary.
divergent
New ocean crust is formed at
divergent boundaries
Evidence about ancient climates indicates that
glacial ice once covered much of what is now India and Australia
Plumes of molten rock originating deep within the mantle are known as ____________.
hot spots
The age of the deepest ocean sediments ____________ with increasing distance from an ocean ridge crest.
increases
According to the property of paleomagnetism
iron-rich rocks show the location of the magnetic poles at the time of their formation
Which of the following statements correctly describes the asthenosphere?
it permits plate motion
If a deep ocean trench is located adjacent to a continent, active volcanoes would likely be found
landward from the trench
Earth's rigid outer layer, consisting of the crust and uppermost mantle, is called the __________.
lithosphere
At a transform fault boundary,
lithosphere is neither destroyed nor produced
The formation of the Hawaiian Islands is associated with
no plate boundary of any kind
What layer of Earth is labeled C in figure 9-1?
oceanic crust
The theory of _______ states that Earth's rigid outer shell is divided into about seven major segments.
plate tectonics
The theory of plate tectonics states that Earth's rigid outer shell is divided into several individual segments called _________.
plates
Magnetic reversals
provide strong evidence for seafloor spreading
an example of a divergent plate boundary on continental lithosphere would be
the East African Rift Valley
A tectonic plate consists of
the crust and uppermost mantle
According to the theory of plate tectonics,
the lithosphere is divided into plates