Deck 3: Plate Tectonics

Question 1

These are areas not connected with plate boundaries but are regions of volcanic activities and are use to monitor the direction and movement of plates are called

A) Divergent plate boundaries.
B) Volcanic areas.
C) Convergent plate boundaries.
D) Hotspots.

Answer 1

D

Question 2

According to plate-tectonic theory,plates of rigid,elastic __________ move over a weak plastic layer below.

A) Lithosphere
B) Asthenosphere
C) Mantle
D) Core

Answer 2

A

Question 3

Example of the movement of the following plates: continent-ocean; continent-continent; ocean-ocean is best referred to as the

A) Divergent plate boundary.
B) Transform plate boundary.
C) Constructive plate boundary.
D) Convergent plate boundary.

Answer 3

D

Question 4

The magnetic dip preserved in a rock indicates

A) How far east or west of north the rock crystallized.
B) The rock's magnetic latitude at the time that it - crystallized.
C) How deep in the crust the magma crystallized.
D) How far from a spreading ridge the rock has traveled.

Question 5

At a convergent plate boundary,

A) Sea floor is produced.
B) High mountains may be built during continent-continent collision.
C) There are very few earthquakes.
D) All of the choices are correct.

Question 6

Divergent plate boundaries

A) Always result in rifts along which new oceanic crust is created.
B) May result in rifts on continents, but may also "fail" or stop, resulting in topographically low areas.
C) Are no longer a potential hazard if they are not actively rifting.
D) Are simple curvilinear features on all ocean floors.

Question 7

A rock's Curie temperature is the temperature above which it

A) Melts.
B) Begins to flow plastically.
C) Loses its magnetism.
D) Ruptures.

Question 8

The Azores Islands

A) Are remnants of rare rift zone volcanoes.
B) Are part of the Aleutian Island volcanic arc.
C) Are, like Hawaii, formed by a Hot Spot.
D) Are not formed by tectonic processes.

Question 9

Stress tending to pull objects apart is __________ stress.

A) Compressive
B) Tensile
C) Shearing
D) Elastic

Question 10

The San Andreas fault is a good example of a

A) Convergent plate boundary.
B) Divergent plate boundary.
C) Transform plate boundary.
D) Hotspot.

Question 11

A ductile material is one that

A) Resists deformation under stress.
B) Conducts electricity well.
C) Readily undergoes plastic deformation.
D) Ruptures easily under stress.

Question 12

Pre-drift reassembly of the continents can be assisted by

A) Polar-wander curves.
B) Matching up the shapes of the corresponding continental margins.
C) Matching up mountain ranges and rock types between once-adjacent continents.
D) All of the choices are correct.

Question 13

With increasing distance from an oceanic ridge,

A) The rocks become older.
B) The rocks become younger.
C) The rocks' ages alternate between younger and older.
D) All of the choices; different patterns occur at different ridges.

Question 14

Sea floor is formed at spreading ridges and destroyed

A) At divergent boundaries.
B) In transform faults.
C) In subduction zones.
D) By magnetic-field reversals.

Question 15

Divergent plate boundaries around the world are indicated by

A) Seafloor spreading.
B) Hotspots.
C) Subduction zones.
D) Both seafloor spreading and subduction zones.

Question 16

Oceanic lithosphere

A) Is made of alternating bands of rocks of different compositions.
B) Is made of alternating bands of rocks of two different ages.
C) Records magnetic "stripes" of normally and reversely magnetized rocks.
D) Moves gradually toward the midocean ridges, where it is consumed.

Question 17

The strength of a rock

A) May depend on how long it has been subjected to stress.
B) Varies with the kind of stress (compressive, tensile or shearing).
C) May be reduced by weathering or fracturing.
D) All of the choices are correct.

Question 18

A "polar-wander" curve shows

A) How magnetic poles have moved on the earth.
B) How the sea floor has spread.
C) How continents have moved or drifted, relative to the magnetic poles.
D) How polar glacier ice has moved across continents.

Question 19

For most solids,sufficiently increased stress results in

A) Breakage.
B) Rupture.
C) Deformation.
D) Transformation.

Question 20

Fossil remains of this animal proved important to the belief that South America and Africa were once joined,then drifted apart

A) Glossopteris.
B) Ichtyosaur.
C) Crinoids.
D) Mesosaur.

Question 21

The earth's polarity has remained the same since its existence.

Question 22

In order for continental drift to occur,the continental lithosphere must behave plastically.

Question 23

Continental drift may explain evidence of past glaciation in regions now located in the tropics,because local climate is strongly controlled by latitude.

Question 24

Plate boundaries were originally located by a French graduate student who plotted the location of all earthquakes and volcanic eruptions world-wide on a map.

Question 25

The locations and ages of islands in the Hawaiian Island chain can be used to show

A) The direction of drift of North America.
B) The rate and direction of movement of the Pacific Plate.
C) The size of earthquakes to be expected in the Pacific Ocean.
D) All of the choices are correct.

Question 26

An island arc comprising of volcanic islands forms as a result of ocean-ocean convergence.

Question 27

Stress is the deformation resulting from the application of strain to a rock.

Question 28

The physical properties of a rock are determined only by grain shapes and sizes and are independent of the kinds of minerals making up the rock.

Question 29

Because the sea floor is protected from weathering,seafloor rocks are better preserved and generally older than continental rocks.

Question 30

Rocks may behave differently over the long spans of geologic time than they do in short-term laboratory experiments.

Question 31

A possible "driving force" for plate motions is

A) Volcanic eruption at hot spots.
B) Shifts in the earth's magnetic field.
C) Convection in the asthenosphere.
D) The weight of subducted continents pulling downward.

Question 32

The idea of continental drift was not proposed until the 1960s,when the first evidence to support it was discovered.

Question 33

Plates move away from each other by 3.5 cm per year at the mid-Atlantic ridge,for a net growth of 7 cm per year for the width of the Atlantic Ocean.How much wider is the Atlantic Ocean today compared to when Columbus discovered the Americas in 1492?

A) About 40 meters
B) About 400 meters
C) About 4 meters
D) About 4 kilometers (4000 meters)

Question 34

Rubber bands show elastic behavior until their elastic limit is exceeded; rocks are always brittle.

Question 35

The remnant magnetism in the rocks is called paleomagnetism.

Question 36

The Appalachian Mountains of eastern North America were formed by continent-continent collision.Today,these mountains are still being uplifted by the same type of collision

A) The Andes Mountains of South America.
B) The Cascade Mountains of North America.
C) The Rocky Mountains of North America.
D) The Himalaya Mountains of Asia.

Question 37

The asthenosphere is a weak,locally partly molten layer over which lithospheric plates can move.

Question 38

Hot spots

A) Move along with plates.
B) Can exist under both oceans and continents, but remain stationary as the plate above moves.
C) result in extrusion of volcanic rocks.
D) Both b and c are correct.

Question 39

Deep in the crust,at elevated temperatures,rocks may behave plastically and undergo folding or flow.

Question 40

Brittle behavior in rocks leads to formation of folds.

Question 41

Plate tectonics are unrelated to the rock cycle and,in fact,has made the rock-cycle concept obsolete.

Question 42

Seawater interacting with hot sea floor at spreading ridges may produce mineral deposits.

Question 43

Although convection in the asthenosphere is widely accepted as the cause of plate movements,it may be that the weight of down-going lithosphere in subduction zones pulls the trailing plate behind it.

Question 44

Rifting occurs at oceanic spreading ridges,but not within continents,because continents are so thick and strong.

Question 45

Satellite data now allow direct measurement of the rates of plate movement,even though it is slow.

Question 46

About 200 million years ago,most of the continents were together,forming a "super continent" called Pangaea.

Question 47

Part of western California is attached to the Pacific Plate,while most of North America belongs to a separate plate.

Question 48

Earthquakes occur at subduction zones,but volcanoes do not because the subducted lithosphere is pushed deep into the mantle.

Question 49

The Hawaiian Islands were formed by repeated volcanic eruptions over a hot spot.

Question 50

The best explanation for the distribution of Glossopteris and Mesosaurus is that they lived when continents on which their fossils are now found were once connected then later were rifted and drifted apart.

Question 51

Transform faults that offset segments of a spreading ridge are formed because rates of spreading are not constant along any one rift zone so shearing develops when one segment grows faster than another.

Question 52

It is not possible to estimate rates of plate movement because new rocks are constantly being created from old.