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