Chapter 9 Review
Wegener's idea that forces might cause continental drift was shown to be impossible when it was
shown that the tidal forces needed to move continents would stop the Earth's rotation
What mechanism of plate motion is illustrated in figure 9-2
slab-pull
The main source of downward convection flow in the mantle is called
slab-push
According to whole-mantle convection
slabs of cold oceanic lithosphere move down into the mantle
What process is illustrated by the area labeled G in figure 9-1
subduction
What kind of plate boundary occurs where two plates grind past each other without destroying of producing lithosphere?
transform fault boundary
What feature is labeled B in figure 9-1
trench
What feature is labeled A in figure 9-2
volcanic island arc
What type of boundary is illustrated in figure 9-2
covergent oceanic-oceanic boundary
How did opponents of continental drift account for the exercise of similar fossil on widely separated continents?
migration across land bridges
The lithospheric plates move an average of
5 centimeters per year
How does the age of the seafloor sediments change with increasing distance from the ocean ridge?
Age increases
Why are subduction zones not commonly found at convergent continental-continental boundaries?
Continental lithosphere is too buyout to be forced down into the mantle
What type of plate boundary is illustrated in Figure 9-1
Convergent oceanic-continental boundary
According to figure 9-2 if the plate labeled H descends into the Earth's interior, what will occur between the position labeled Y and X
Earthquake foci will be shallower at Y and increase the depth
Where are most transform faults found?
Joining two segments of a mid-ocean ridge
At a transform fault boundary
Lithosphere is neither destroyed nor produced
Which of the following does not occur at a subduction zone
The leading edge of both plates are bent upward
What do the strips of low-intensity magnetism represent on the ocean floor
area where the rocks have reversed polarity
The Red Sea is theorized to be the site recently formed
divergent boundary
Evidence about ancient climates indicates that
glacial ice once covered much of what is now India and Australia
The downward sliding characteristic of ridge-push is the result of
gravity
If a deep ocean trench is located adjacent to a continent, active volcanoes would likely be found
landward from the trench
What layer of the Earth is labeled C in figure 9-1
oceanic crust
The age of the rock that makes up the ocean floor was determined by
radiometric dating
