2. Plate tectonics helps explain the growth

and distribution of mountains but gives no clues to the birth of continents.
and distribution of mountains and their presence along the margins of plates.
of mountains and their presence along plate margins but gives no clues to the formation of cratons.
and distribution of mountains but gives no clues to the formation of shields.

3. During the early time of continental crustal formation on Earth (3-4 billion years ago), smaller plates

broke away from cratons to form continents.
broke away from shield areas to form continents.
accreted with shields to form thicker plates.
accreted with island arcs to form larger plates.

4. Most geologists believe that

the original plates were small but thick.
originally the lithosphere was thinner and convection was faster.
the original continents were larger and thinner.
the original plates were more rigid.

5. As one moves away from the craton

the continent becomes younger.
accreted terranes are always found first.
very highly eroded mountain ranges are always found.
active volcanic mountain ranges are found first.

6. One connection between ocean basins and mountains is that

ocean basins create the volcanic activity that is transferred to land by plate action.
ocean basins create the volcanic material that is always uplifted to form mountains.
sediment is carried into the sea, forms rock and then plate activity may push it up into mountains.
sediment is carried into the sea, it is uplifted and later forms into rock.

7. In addition to forming volcanic mountains, subduction can help in the creation of mountains by

producing small plates that become "scraped off" and "glued" to the edges of continents.
"scraping off" seamounts and island arcs that then become "glued" to a continental margin.
producing mantle plumes which push up the edges of continents.
producing small plates that become "glued" to the edges of continents.

8. Accreted terranes are

recognized by their distinct composition and boundaries that are marked by faults or belts of ocean sediment.
recognized by their distinctive shapes and boundaries marked by faults.
recognized mainly by distinctive radioactive rock.
found only in the northwest and Alaska.

9. The area on Earth where accreted terranes originated can often be determined by the

the fossils in the terrane and the age of the rock.
the fossils in the terrane and the magnetic patterns in the rock.
the age of the rock and the magnetic patterns in the rock.
the direction of faulting and the fossils in the terrane.

10. When subduction ceases

divergence begins to form ridges.
accretion ends and divergence begins.
mountain building ends and accretion begins.
mountain building and accretion end and erosion takes over.

11. As mountains erode,

they become lower very quickly.
their softer roots become exposed.
they are pushed up by the stiffer mantle under their low density roots.
their compositions change because the softer root material pushes up through them.

12. The concept of isostasy basically means that

the mantle must be a liquid.
that the crust is "floating" on the mantle.
that asthenospheric pressure is equalized.
that lithospheric pressure is redirected horizontally.

13. The oldest portions of continents usually involve

accreted terrane.
active volcanic mountain ranges.
an active collision boundary.
highly eroded mountain ranges.

14. The phrase, "Dance of the Continents" (ie the Wilson Cycle) refers mainly to the last

several hundred million years of plate drifting and rotation.
several hundred million years of plates coming together, forming mountains and breaking apart.
several billion years of plate drifting, sinking and rising.
several billion years of plates drifting and rotating.

Lesson 8 "The Earth's Structures"

15. The main classes of structures formed by deformation are unconformities,

fractures/faults.
mountains and faults.
ocean basins and faults.
fractures/faults and folds.

16. What conditions tend to make rocks bend or flow? Choose the most complete answer.

high pressures and temperatures
high pressures and soft rock
high temperatures and slow stresses
high temperatures, high pressures and slow stresses

17. Basic forms of folding are

synclines that are upfolded and anticlines that are downfolded.
synclines that are downfolded and anticlines that are upfolded.
synclines that are upfolded and monclines that are downfolded.
anticlines that are downfolded and monclines that are upfolded.

18. Fracture tends to occur

in the shallow crust where rocks are softer.
where rocks are softer and cooler.
in areas of the shallow crust where stresses work rapidly and rocks are cooler and brittle.
where rocks shatter easily.

19. Faults are named according to their motion along the plane of rupture. Correct examples are:

dip-slip : vertical motion; transform : vertical motion
dip-slip : vertical motion; strike-slip : horizontal motion
dip-slip : horizontal motion; strike-slip : vertical motion
dip-slip : horizontal motion; strike-slip : horizontal motion

20. Examples of dip-slip faulting would be given by

reverse, normal and thrust faults.
reverse, normal and right lateral faults.
reverse, normal and left lateral faults.
normal, thrust faults and oblique faults.

21. Rock will break when its

flexible strain limit is exceeded.
plastic strain limit is reached.
elastic limit is exceeded.
elastic limit is reached.

22. Most folds are created by

tensional stress.
joints or fractures.
faults.
compressional stress.

23. An unconformity always has which of the following processes associated with it?

burial of an area followed by erosion.
erosion followed by burial of the eroded surface.
erosion, faulting, followed by burial of the surface.
erosion, folding, followed by burial of the surface.

24. The unconformity that usually shows the least amount of time between the formation of its lower level and renewed deposition on top is a

disconformity; a nonconformity shows the most.
nonconformity; a disconformity shows the most.
disconformity; an angular unconformity shows the most.
nonconformity; an angular unconformity shows the most.

25. Which of the following are the most important factors considered by petroleum geologist as they analyze their drill core samples for oil?

The temperature and age of the rock.
The age and hardness of the rocks.
The temperature, depth, age, source of the rocks and the possible presence of a "trap."
The temperature, depth and hardness of rock.

Prepared by: Mike Mitchell

Be sure to review your quizzes before taking the test.