Question 1

Why do we know that apparent polar wander didn't actually happen, and that the poles have remained more or less where they are now?

Accepted Answer

The answer of Why do we know that apparent polar...

Question 2

At what point does the Wadati-Benioff zone have to end?

Accepted Answer

A)  when it runs into the deep-sea trench 
B)  when it runs up against another plate 
C)  when it reaches a zone that is too hot 
D)  when it reaches Earth's surface

Question 3

Which is not a piece of primary evidence in favor of the mantle-plume hypothesis?

Accepted Answer

A)  basalt composition 
B)  volcanic locations 
C)  hot spot volcano types 
D)  plate velocity

Question 4

Approximately what percent of lithosphere deformation occurs at plate boundaries?

Accepted Answer

A)  60% 
B)  70% 
C)  80% 
D)  90%

Question 5

Why did scientists reject Wegener's idea about how continents moved from Pangea to their present locations?

Accepted Answer

A)  Scientists did not believe in a fluid mantle. 
B)  Scientists did not believe in uplift of continents from the ocean floor. 
C)  Scientists did not believe that the continental lithosphere could be stronger than the oceanic lithosphere. 
D)  Scientists were not convinced by his puzzle-like matching of continents into Pangea.

Question 6

Figure 12.25 
-Using Figure 12.25 in your textbook, which of the following is not a normal consequence of an oceanic-oceanic convergent plate boundary?

Accepted Answer

A)  The denser crust subducts the less dense plate. 
B)  Thrust faults lift up above the subduction zone. 
C)  A volcanic island arc forms above where the subducting plate melts. 
D)  A trench forms at the location where subduction begins.

Question 7

At convergent boundaries earthquake focal depths ________ with increasing distance from the trench.

Accepted Answer

A)  decrease 
B)  erupt 
C)  increase 
D)  rotate

Question 8

What is the main frame of reference for GPS measurements?

Accepted Answer

A)  rock compositions 
B)  satellite locations 
C)  Earth's magnetic pole 
D)  the absolute value of Earth's core

Question 9

What are the consequences of plate motion over geologic time?

Accepted Answer

The answer of What are the consequences of plate motion...

Question 10

How far down do downwelling and upwelling reach in the Earth?

Accepted Answer

A)  to the lithosphere 
B)  to the asthenosphere 
C)  to the transition zone 
D)  to the lower mantle

Question 11

How fast is North America moving away from Africa?

Accepted Answer

A)  3 cm/year 
B)  3 m/year 
C)  3 mm/year 
D)  3 km/year

Question 12

What evidence shows that Yellowstone is a hot spot?

Accepted Answer

A)  basalt flows 
B)  extinct volcanoes 
C)  a geyser 
D)  metamorphic rock banding

Question 13

What two types of locations are hot spots typically found in?

Accepted Answer

The answer of What two types of locations are hot...

Question 14

Which of the following plates has the fastest average velocity?

Accepted Answer

A)  North American Plate 
B)  Nazca Plate 
C)  Cocos Plate 
D)  Pacific Plate 
E)  Philippine Plate

Question 15

Which statement is true about the lithosphere?

Accepted Answer

A)  The lithosphere is thickest at the mid-ocean ridges because of the quantity of magma that flows up to the surface. 
B)  The lithosphere gets thicker as distance from the ridge increases, because it cools and the boundary between the lithosphere and asthenosphere occurs at greater depth. 
C)  The lithosphere maintains its thickness as distance from the ridge increases, because the boundary between the lithosphere and asthenosphere remains at a constant temperature and depth. 
D)  The lithosphere gets thinner as distance from the ridge increases, because decompression melting occurs with decreased pressure.

Question 16

The following statements relate to processes that occur because of plate subduction. Which of the following statements is not true?

Accepted Answer

A)  Earthquake foci are deeper further from a deep-sea trench. 
B)  Mountains form further from a convergent boundary than from a divergent boundary. 
C)  Volcanoes of this kind tend to have a single type of magma. 
D)  Deep-sea trenches mark the plate boundary.

Question 17

Which feature is not usually caused by convergent boundaries?

Accepted Answer

A)  volcanoes 
B)  deep-sea trenches 
C)  rift valleys 
D)  mountains

Question 18

Using Figure 12.11 in your textbook, which option correctly identifies a time that polarity changed from normal to reverse and back?

Accepted Answer

A)  normal to reverse: 3.04 million years ago, reverse to normal: 2.60 million years ago 
B)  normal to reverse: 2.60 million years ago, reverse to normal: 1.79 million years ago 
C)  normal to reverse: 3.33 million years ago, reverse to normal: 3.04 million years ago 
D)  normal to reverse: 1.79 million years ago, reverse to normal: 0.99 million years ago

Question 19

After movement, the interior parts of ice slabs and continental plates

Accepted Answer

A)  may be stretched. 
B)  may be rippled up to form hills, ridges, and mountains. 
C)  may be cracked to form crevices. 
D)  remain unchanged.

Question 20

Which of the following is true of divergent and convergent plate movement?

Accepted Answer

A)  The direction of plate movement is the same. 
B)  Convergent plate movement is less symmetrical than divergent plate movement. 
C)  Material is destroyed with both plate movements. 
D)  Both plates have boundaries.

Exam 12: Global Tectonics: Plates and Plumes