Geology 117: The Oceans

Self-Administered Quizzes

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Quiz No. 2 -- Covers Topics 6 -10

1. Continental shelves

A. are very broad along mountainous, rugged coastlines (like California)

B. are usually narrow along mountainous, rugged coastlines (like California)

C. are usually narrow along flat coastlines with no mountains (like South Carolina)

D. none of the above

 

2. Deep ocean trenches

A. are more common in the Atlantic than in the Pacific

B. are more common in the Pacific than in the Atlantic

C. are most common in the Indian Ocean

D. are equally common in all oceans

 

3. The oldest oceanic crust is about

A. 200 years old

B. 4.3 Billion years old

C. 15 m.y. (million years( old

D. 180 m.y. old.

 

4. The motion of lithospheric plates is driven by

A. forces caused by Earth's rotation

B. magnetic fields in the earth's outer core

C. convection in the mantle

D. heat buildup in the lithosphere

 

5. Mid-ocean ridges form at

A. All plate boundaries

B. convergent plate boundaries

C. divergent plate boundaries

D. Transform plate boundaries

 

6. Earthquakes occur most often at

A. the boundaries between lithospheric plates

B. the weak interiors of continental plates

C. abyssal plains

D. the base of the mantle where it moves over the core

 

7. The steepest part of the continental margin is the:

A. rise

B. slope

C. plain

D. shelf

E. None of the above.

 

8. Which of the following are characteristic of subduction zones?

A. deep trenches
B. deep, strong earthquakes
C. volcanic island arc systems
D. All of these are correct.
E. None of these are correct.

 

9. The symmetric pattern of magnetic "stripes" (="anomalies") parallel to mid-ocean ridge systems indicate that

A. oceanic crust with and without iron are formed at mid-ocean ridges.
B. the temperature of oceanic-crust crystallization varied.
C. sediments are thinner over mid-ocean ridges than elsewhere in the oceans.
D. oceanic crust is continuously produced through intervals of "normal" and
"reversed" polarity of Earth's magnetic field.
E. the intensity of Earth/s magnetic field decreases away from mid-ocean ridges.

 

10. Which of the following features of the deep-ocean floor is not a result of volcanic activity?

A. Coral atolls

B. Guyots

C. Fracture zones

D. Abyssal hills

E. Island/seamount chains.

 

11. Submarine canyons on continental margins are probably the result of:

A. erosion by sediments that move down off the shelf

B. transform fault motion.

C. earthquake activity.

D. subduction of continental crust.

E. rifting of the continental margin.

 

12. According to the principles of plate tectonics and sea-floor spreading, deep trenches around the margins of ocean basins are sites where:

A. continental crust is created.

B. continental crust is destroyed.

C. oceanic crust is created.

D. oceanic crust is destroyed.

E. crustal plates move past one another along a fault.

 

13. Plates move horizontially past each other along

A. transform faults.
B. convergent plate boundaries.
C. divergent plate boundaries.
D. the transition between continental and oceanic crust.
E. mantle plumes

 

 

Answers: 1=B, 2=B, 3=D, 4=C, 5=C, 6=A, 7=B, 8=D, 9=D, 10=C, 11=A, 12=D, 13=A