GEOL 215 Test One

Total Flash Cards » 75
 
1. 

Who proposed the theory of continental drift?

 

Alfred Wegener

 
2. 

Which of the following concepts was developed earliest?

 

continental drift

 
3. 

How old are the fossils of the reptile

Mesosaurus found in Africa and South America

that suggest the two continents were once together?

 

about 300 million years old

 
4. 

When was the theory of plate tectonics developed?

 

1960s

 
5. 

Where is new lithosphere created?

 

divergent plate boundaries

 
6. 

Where does volcanism occur?

 

convergent plate boundaries and divergent plate boundaries

 
7. 

Where are the world's highest mountain ranges created?

 

Convergent plate boundries

 
8. 

Which type(s) of plate boundaries indicate(s) the direction of relative plate motions

 

transform fault boundries

 
9. 

New lithosphere is created ____________.

 

at mid-ocean ridges

 
10. 

What type of plate boundary is shown in the diagram?

 

a subduction zone

 
11. 

Which of the following locations could be represented by the diagram?

 

the west coast of South America

 
12. 

In which ocean are most of the world's convergent plate margins located?

 

Pacific Ocean

 
13. 

The east coast of North America is __________.

 

not a plate boundary

 
14. 

Which of the following is associated with a divergent plate boundary?

 

earthquakes

volcanism

rifting

all of the above

 
15. 

Which of the following is a divergent plate boundary?

 

the Mid-Atlantic Ridge

 
16. 

At what type of plate boundary do the deepest earthquakes occur?

 

convergent

 
17. 

Approximately how deep (below sea level) are the deepest deep-sea trenches?

 

10 km

 
18. 

Which of the following is not associated with convergent plate boundaries?

 

spreading centers

 
19. 

Which of the following is a type of convergent plate boundary?

 

subduction zone

 
20. 

Which of the following mountain ranges formed as a result of ocean-continent

convergence?

 

the Andes

 
21. 

When a deep-sea trench is located next to a continent, where would you expect to find

active volcanoes?

 

on the continent side of the trench

 
22. 

What plate is subducting beneath southwestern Canada and the northwestern United

States?

 

the Juan de Fuca Plate

 
23. 

The west coast of South America is __________.

 

a convergent plate boundary

 
24. 

Which of the following is an example of a transform plate boundary?

 

the San Andreas Fault

 
25. 

What type of plate boundary is parallel to the direction of plate movement?

 

transform plate boundary

 
26. 

Which of the following mountain ranges is the product of continent-continent

convergence?

 

the Himalayas

 
27. 

The North American Plate is bounded by ______ plate boundaries.

 

convergent, divergent and transform

 
28. 

Which of the following can be used to determine the rates of plate motion? ( )

 

astronomical positioning

seafloor magnetic anomalies

global positioning system

D) all of the above

 
29. 

The questions refer to this cross section, which depicts magnetized oceanic crust at a spreading

center. The “+” symbol indicates positive (normal) magnetic anomalies; the “–” symbol

indicates negative (reverse d) magnetic anomalies.

How fast are points C and D spreading apart from each other?

 

about 100 millimeters/year

 
30. 

The questions refer to this cross section, which depicts magnetized oceanic crust at a spreading

center. The “+” symbol indicates positive (normal) magnetic anomalies; the “–” symbol

indicates negative (reverse d) magnetic anomalies.

“Normal” magnetized crust at the spreading center formed during the ________ epoch.

 

Brunhes

 
31. 

Modern seafloor spreading rates range from _________.

 

2 to 15 centimeters per year

 
32. 

What two scientists related the positive and negative magnetic bands on the seafloor to

seafloor spreading?

 

F.J. Vine and D.H. Mathews

 
33. 

Which of the following is commonly used to determine the age of seafloor samples

recovered by the deep-sea drilling project?

 

foraminifera fossils

 
34. 

Which of the following plates is moving the fastest?

 

the Pacific Plate

 
35. 

On a map of the seafloor, the boundaries between normally magnetized oceanic crust

and reversely magnetized oceanic crust are called __________.

 

isochrons

 
36. 

When was the supercontinent of Pangaea assembled?

 

approximately 250 million years ago

 
37. 

How old are the oldest rocks on the ocean floor?

 

about 200 million years old

 
38. 

The oldest continental rocks are __________ than the oldest oceanic rocks.

 

much older

 
39. 

Isochrons on the seafloor are roughly __________ the ridge axis along which they were

created.

 

parallel to and symmetic about

 
40. 

Why are isochrons on the Pacific seafloor more widely spaced than isochrons on the

Atlantic seafloor?

 

the pacific seafloor formed at a faster spreading rate than the Atlantic seafloor

 
41. 

What ocean used to lie between Africa and Eurasia and was the ancestor to today's

Mediterranean Sea?

 

Tethys

 
42. 

When did the supercontinent Pangaea begin to break apart?

 

about 200 million years ago

 
43. 

Pangaea split into two continents: Laurasia, made up of the northern continents, and

______, made up of the southern continents.

 

Gondwana

 
44. 

When did India begin to collide with Asia to form the Himalayas?

 

about 50 million years ago

 
45. 

Compared to slower moving plates, faster moving plates are bounded by a greater

proportion of __________.

 

subduction zones

 
46. 

What drives plate tectonics?

 

mantle convection

 
47. 

Which of the following forces is important in driving plate tectonics?

 

A) the pulling force of a sinking lithospheric slab

B) the pushing force of a plate sliding off a mid-ocean ridge

C) the suction force of a retreating subduction zone

D) all of the above

 
48. 

How deep are plates subducted?

 

2900 km

 
49. 

Regions of intense localized volcanism such as Hawaii form above plumes of fast-rising

material that originate in the __________.

 

deep mantle

 
50. 

The Hawaiian volcanoes are __________.

 

not located at a plate boundary

 
51. 

The Earth's lithosphere is broken up into approximately _____ large plates.

 

12

 
52. 

New oceanic crust is created at ________.

 

mid-ocean ridges

 
53. 

Shallow focus earthquakes are associated with which type of plate boundary?

 

A) divergent

B) convergent

C) transform

D) all of the above

 
54. 

Mid-ocean ridges are also referred to as _________.

 

spreading centers

 
55. 

An island arc forms when there is __________ convergence

 

ocean-ocean

 
56. 

The convergence of the North American Plate with the Juan de Fuca Plate forms the

______ subduction zone.

 

Cascadia

 
57. 

Mount St. Helens is part of the ____________.

 

Cascade Range

 
58. 

The Great Rift Valley of East Africa is an early-stage _________.

 

divergent boundary

 
59. 

The Appalachian Mountains formed from an ancient ____________ plate boundary.

 

convergent

 
60. 

Oceanic crust that records negative magnetic anomalies formed when the Earth's

magnetic field was ___________.

 

reversed from what it is today

 
61. 

Astronomical positioning measures points on the Earth's surface relative to ________.

 

the position of fixed stars

 
62. 

If the position between antennas on two plates moving away from each other changes by

5 mm/yr, then each plate is moving at approximately ______.

 

2.5 mm/yr

 
63. 

Rhodinia is a supercontinent that formed __________.

 

before Pangea

 
64. 

Fifty million years in the future geoscientists predict the east coast of North America

will be _____________.

 

a convergent plate boundary

 
65. 

The main type of plate boundaries are (proper names only): __________.

 

convergent, transform, divergent

 
66. 

What kind of plate boundary defines the eastern edge of the plate we live on here in the

United States?

 

mid-ocean rift

 
67. 

How do we determine absolute direction of plate movement over millions of years?

 

with seafloor isochrons

 
68. 

__________ are the most extensive mountain ranges on Earth today.

 

mid-oceanic ridges

 
69. 

Who first described world tectonics in terms of rigid plates?

 

Tuzo Wilson

 
70. 

Who first proposed the three different kinds of plate boundaries widely accepted today

 

Tuzo Wilson

 
71. 

Which of the following locations is least likely to have active volcanoes?

 

transform fault

 
72. 

How many major plates cover the Earth's surface?

 

12

 
73. 

Which of the following plates is the largest?

 

A) Cocos Plate

B) Indian Plate

C) North American Plate

D) Pacific Plate

 
74. 

Which of the following plates contains only oceanic crust?

 

Nazca Plate

 
75. 

Who first suggested that the Earth's surface might be a fragile shell resting on fluid?

 

Alfred Wegener