Geology 131 Study Guide Ch2

Front 1

What is the term for the supercontinent of the present day southern continents?

Back 1

Gondwana

Front 2

What is the term for Wegener's explanation of continent movement?

Back 2

Continental Drift

Front 3

What is the term for the supercontinent combining all continents?

Back 3

Pangaea

Front 4

What is the term for the supercontinent of North America, Greenland, Europe, Asia?

Back 4

Laurasia

Front 5

What is the term for the remnant magnetism in ancient rocks?

Back 5

Paleomagnetism

Front 6

What is the term for Hess's explanation of the formation of ocean crust?

Back 6

Sea Floor Spreading

Front 7

What is the term for the circulation where hot magma rises, cold crust sinks?

Back 7

Thermal Convection

Front 8

What is the term for the deviations from average strength of magnetic field?

Back 8

Magnetic anomalies

Front 9

What is the term for the variable sized peices of lithosphere, also called "slabs"?

Back 9

Plate

Front 10

What is the term for the current geological explanation of Earth's behavior?

Back 10

Plate tectonics

Front 11

What is the term for the plate boundary where new ocean lithosphere forms?

Back 11

Divergent

Front 12

What is the term for the plate boundary where ocean lithosphere is consumed?

Back 12

Convergent

Front 13

What is the term for the plate boundary where plates slide past one another?

Back 13

Transform

Front 14

What is the term for the zone of intensely deformed rocks between trench and arc?

Back 14

Melange

Front 15

What is the term for locations where stationary magma plumes form volcanoes?

Back 15

Hot spot

Front 16

Name 3 landforms whose positions are dictated by the interactions between plates?

Back 16

1. Continents
2. Oceans
3. Mountains

Front 17

Name the 3 land forms that affect EArth's climate?

Back 17

1. Continents
2. Oceans
3. Mountains

Front 18

When is the fit of continents in Pangaea the closest and best?

Back 18

When matching jup the edges of the continental slope where continental crust ends

Front 19

What does paleomagnetism record?

Back 19

The direction of the EArth's magnetic pole at the time of the rock's formation

Front 20

Name 3 reasons ancient rifts may be recognized?

Back 20

Associations of:
1. Faults
2. Intrusions
3. Thousands of feet of continental sediments

Front 21

How are absolute rates of plate motion best calculated?

Back 21

Using hot spots as reference points

Front 22

Where do hot spots form?

Back 22

Above mantle plumes

Front 23

What 3 things in combination probably cause plate motion:

Back 23

1. mantle convection
2. Ridge-push
3. Slab-pull

Front 24

What 2 things form many metallic ore deposits?

Back 24

1.Igneous
2. Hydrothermal Activity

Front 25

What is the distribution of metallic ore deposits dependent on?

Back 25

Plate tectonic history

Front 26

How has seafloor spreading been proved

Back 26

Dating
1. Sediments on ocean crust and
2. Rocks on oceanic islands

Front 27

Name the 2 ways ancient plate boundaries are recognized?

Back 27

1. Characteristic rock types
2. Geologic Structures

Front 28

Name the 2 actions that EArth's continents are constantly doing?

Back 28

1. Combining
2. Separating

Front 29

Approx. how long are continental cycles?

Back 29

500 million years

Front 30

Name the 4 fossils distributed that are evidence for Pangaea?

Back 30

1. Glossopteris seed ferns
2. freshwater Mesosaurs
3. terrestrial Lystrosaurus
4. Land-dwelling Cynognathus

Front 31

Name 4 parts of Hess's proposals:

Back 31

1. Continent crust and ocean crust can move together
2. New ocean crust forms at mid-ocean ridges
3. Thermal convection drives the movement of the crust
4. Magma rises at mid-ocean ridges

Front 32

Name 4 characteristics of divergent plat boundaries:

Back 32

1. New ocean lithosphere forms
2. Basaltic magma erupts
3. Crust is thinned and extended
4. Shallow focus earthquakes occur

Front 33

How do volcanic island arcs form?

Back 33

Adjacent and parallel to ocean trenches.

Front 34

How are plate motion speeds estimated?

Back 34

1. Dating magmatic anomalies
2. Satellite laser ranging techniques
3. Dividing age of sediment by distance from spreading ridge
4. Dating volcanoes in a hot spot track

Front 35

What are the 2 reasons why plate movements influence the distriubtion of life on Earth?

Back 35

1. They can create geographic barriers such as mountains and oceans
2. They can cause climate change by moving continents into different latitudes

Front 36

Name 4 characteristics of the Sumatran earthquake and tsunami of December 26, 2004:

Back 36

1. Was caused by the motion of tectonic plates
2. Could happen again
3. Is a natural and tragic part of life on a dynamic planet
4. Could not be controlled since it was driven by forces deep within the Earth

Front 37

Who developed the theory of plate tectonics?

Back 37

1. J. Tuzo Wilson
2. Wegener
3. Hess

Front 38

Name 4 explanations that the existence and location of pangaea elegantly explains?

Back 38

1. Distribution of ancient glacial rocks
2. Direction of ice flow in ancient glaciers
3. Why Maine used to be near the equator
4. Abrupt termination of some ancient mountain ranges

Front 39

T o F
Geologists are not sure exactly how convection behaves in the mantle since the plastic asthenosphere and the rigid lower mantle differ in behavior and properties.

Back 39

TRUE

Front 40

What od magnetic minerals in ancient rocks record?

Back 40

The rocks location relative to the magnetic pole

Front 41

T or F
Magnetic reversal anomalies are symmetric about ocean ridge systems.

Back 41

TRUE

Front 42

Where does ocean crust form?

Back 42

At Ocean ridges

Front 43

How far do you need to drill all the way through a tectonic plate?

Back 43

Need to go down over 100 km

Front 44

Where are ocean plates the thickest?

Back 44

Farthest away from ridges

Front 45

Compared to the asthenosphere, is the lithosphere warmer or colder?

Back 45

Colder

Front 46

T or F
Pangaea was the world's latest in a series of supercontinents.

Back 46

TRUE

Front 47

How do scientists think cliffs on Mercury formed?

Back 47

From impacts and
Contraction

Front 48

What are 4 characteristics of Olympus Mons?

Back 48

1. 3 times the size of a Hawaiian volcano
2. It was over its magma source for millions of years
3. Martian lithosphere must be thick and strong to hold its huge weight up
4. Marian tectonics didn't involve lots of horizontal motion while it was forming
5. Marian and Terrestrial tectonics are probably very different

Front 49

On what celestial body in our solar system are the fewest impact craters seen?

Back 49

Io

Front 50

Why does rifting begin in continents?

Back 50

Because rocks are poor conductors of heat, and
Continents are thicker

Front 51

In what direction does the mid-Atlantic ridge run?

Back 51

North-South

Front 52

In what direction is the continent of South America moving primarily?

Back 52

West

Front 53

What is preserved in the rock record as evidence of ancient rifts?

Back 53

Thick layers of continental sediments cut by faults and dikes

Front 54

When does a low angle of dip of a subducting plate result?

Back 54

When subduction is fast

Front 55

What happens when an oceanic and a continental plate converge?

Back 55

The denser plate subducts

Front 56

What is the cause for the world's highest mountain chain?

Back 56

Continental collisions

Front 57

What does a large, linear zone of folded, faulted, and metamorphosed rock record?

Back 57

The location of an ancient collision

Front 58

What do transform boundaries generate?

Back 58

Numerous shallow focus quakes

Front 59

List 4 characteristics of hot spots?

Back 59

1. Formed over relatively stationary mantle plumes
2. Create volcanoes
3. Record the motion of the plates
4. Found under both continental and ocean crust

Front 60

T or F
Tectonic plates can change direction.

Back 60

TRUE

Front 61

T or F
Knowledge of plate tectonics can predict where earthquakes, volcanoes, and mineral resources will occur.

Back 61

TRUE

Front 62

T or F
Early evidence for plate tectonics came from the coastline fit of eastern South America with west Africa.

Back 62

TRUE

Front 63

T or F
If the continents had never moved, paleomagnetic data would indicate that the Earth has had multiple, moving magnetic poles.

Back 63

TRUE

Front 64

T or F
Magnetic reversals are exceedingly rare in the earth's past.

Back 64

FALSE

Front 65

T or F
The oldest continent crust is approximately 22 times older than the oldest ocean crust.

Back 65

TRUE

Front 66

T or F
Because the rate of divergence exceeds that of convergence, the Earth is expanding.

Back 66

FALSE

Front 67

T or F
Convergent boundaries vary depending on the type of crust involved.

Back 67

TRUE

Front 68

T or F
Gravity helps drive the plates through slab pull and ridge push.

Back 68

TRUE

Front 69

T or F
Ancient transofrm boundaries are easy to recognize because of the distincitive sequence of rocks they create.

Back 69

FALSE

Front 70

T or F
The formation of the Panama Isthmus caused evolution of new species of marine invertebrates and extinction of many land vertebrates.

Back 70

TRUE