OCE 1001 Chapter 2

lithosphere; asthenosphere

Tectonic plates are pieces of the ________ that float on the more fluid ________ below.

your fingernails grow

Tectonic plates move about as fast as ________.

convergent

The Himalayan Mountains and Alps are geographic examples of which type of plate boundary?

divergent plate boundary

The Mid-Atlantic Ridge is an example of a:

declining

The Pacific Ocean is an example of the ________ stage of the Wilson Cycle.

a single volcano

What surface feature would you expect to form if both a hot spot and a tectonic plate are stationary?

Oceanic-oceanic convergent boundaries

What type of plate boundary will result in the formation of a volcanic island chain or arc near a deep-sea trench?

a supercontinent that formed 300 million years ago

What was Pangea?

Pangaea

What was the name for the supercontinent about 200 million years ago?

The mechanism for the movement of the plates

What was the one line of evidence that Alfred Wegner could not explain with continental drift?

The Earth would increase in volume

What would happen to Earth if ocean floor were created at divergent boundaries at a faster rate than it is destroyed at convergent boundaries?

450 million years ago

When did the Appalachian Mountains of North America begin to form?

50 million years ago

When did the great mountain ranges of southern Europe and Asia begin to form?

when a continent is broken apart by a divergent boundary

When do new oceans form?

prior to 600 million years ago

When was the Precambrian eon?

when the volcano is carried away from the hot spot by the tectonic plate

When will a hot-spot volcano become extinct?

at mid-ocean ridges

Where are most modern divergent plate boundaries found?

Greenland and Antarctica

Where are the only two places in the world where continental ice sheets occur today?

In tropical latitudes

Where do coral reefs exist with sea mounts?

within continents

Where do most divergent boundaries originate?

along the crest of mid-ocean ridges

Where is the youngest ocean floor found?

ocean trenches and volcanoes

Which geologic features are associated with convergent boundaries?

mid-ocean ridges and continental rift valleys

Which geologic features are associated with divergent boundaries?

The direction of plate motion shifted over time over a stationary mantle plume (hotspot).

Which hypothesis best explains the continuous bend in the Hawaiian Islands-Emperor Seamount chain?

Fringing reef, barrier reef, atoll

Which is the correct order of coral reef development near seamounts?

pacific

Which is the largest tectonic plate?

mesosaurus

Which of the following fossils was used as data to help reconstruct Pangea because it was a reptile found in South America and Africa?

Hawaiian Islands-Emperor Seamount Chain

Which of the following is an example of a nematath?

East Africa

Which of the following is an example of the embryonic stage of the Wilson Cycle?

uplifted mountain ranges

Which of the following is characteristic of continental-continental convergent plate boundaries?

Andes and Cascades

Which of the following mountain ranges are examples of continental arcs?

Coral reefs at the ocean surface grow away from seamounts over time.

Which of the following statements about coral reefs and seamounts is most accurate?

The lithosphere is composed of the crust and the uppermost portion of the mantle.

Which of the following statements is true of the lithosphere?

magnetosphere

Which sphere of the Earth protects life on Earth from solar storms?

normal faulting

Which type of faulting is associated with the development of new ocean floor?

High-density oceanic crust subducts beneath low-density continental crust where plates converge

Why are ocean basins continually being destroyed and created, rather than simply being redistributed around Earth's surface like continents?

decompression of rock

What causes melting of material under divergent plate boundaries?

They were nothing like the continent shapes we see on Earth today

What did the continents that formed during the break-up of the supercontinent 600 million years ago look like?

volcanoes within tectonic plates

What surface feature provides evidence for the location of hot spots?

andesitic volcanoes

Which of the following is characteristic of oceanic-continental convergent plate boundaries?

Spinning of the metal cores

Which of the following is responsible for generating Earth's magnetic field?

Convection in the liquid iron-nickel outer core generates a magnetic field

Which of the following is the main reason that Earth has a magnetic field?

The oceanic pattern of alternating reversals of Earth's magnetic field

Which of the following is the most convincing piece of evidence set forth to support the concept of sea floor spreading?

The inner core is solid and the outer core is liquid, and they are both composed mainly of iron and nickel.

Which of the following statements is true regarding the layer(s) of Earth that is/are responsible for the magnetic field?

Paleomagnetic reversals

Which of the following was not used as evidence for continental drift?

plate tectonics

Which process causes the surface geography of Earth to change over time?

Seamounts subside as tectonic plates move. Coral reefs grow away from the seamount in order to stay near the sunlight.

Why do coral reefs at the ocean surface grow away from seamounts over time?

a symmetrical pattern of normal and reverse magnetization in ocean crustal rocks along ridges and rises

Evidence shows that periodic reversals of Earth's magnetic field have resulted in __________.

plants lived in the tropics, but landmasses have drifted to current locations.

Fossils of ancient tropical plants are currently found near the poles because the:

the magnetic pattern of rocks on the seafloor.

Frederick Vine and Drummond Matthews determined that new ocean floor was being produced at ocean ridges by examining:

The angle of magnetic field lines changes depending on where you are on Earth's surface. They are more perpendicular to Earth's surface at the poles and more parallel at the equator.

How can a dip needle be used to determine one's location on Earth?

They create loops from the center of the Earth that exit in the south and enter in the north.

How do Earth's magnetic field lines of force currently behave?

a continental-continental divergent

The Red Sea is an example of ________ plate boundary.

Pacific Plate and North American Plate

The San Andreas Fault in California cuts through which two plates?

5,000

The flipping of Earth's magnetic field takes an average of about ________ years.

australia

The largest reef system in the world is the Great Barrier Reef. Where is it located?

paleogeography

The study of historical changes of continental shapes and positions is called:

western Pacific

To find the largest area of the ocean with the oldest ocean crust, you should go to the ________.

one large continent surrounded by ocean

What did the surface of Earth look like 600 million years ago?

They are all associated with zones of earthquakes.

What do all plate boundaries have in common?

An active volcano that occurs along the crest of the mid-ocean ridge.

What is a seamount?

A seamount that grew above sea level, experienced wave erosion, and is now inactive

What is a tablemount?

a row of volcanoes that forms on the overriding plate near a subduction zone

What is a volcanic arc?

Barrier reefs surround an inactive volcano emerging above sea level, while atolls surround the previous location of a submerged volcano.

What is the difference between a barrier reef and an atoll?

The Earth's axis runs through the geographic North Pole. The magnetic North Pole is the point at which Earth's magnetic field points directly downward.

What is the difference between the geographic North Pole and the magnetic North Pole?

Convergence (subduction)

What is the motion of a declining stage of the Wilson cycle?

divergence

What is the motion of a juvenile stage of the Wilson cycle?

The crust is part of the lithosphere.

What is the relationship between the crust and lithosphere?

All of the crust is contained within a larger layer called the lithosphere.

What is the relationship between the crust and the lithosphere?

continental margin

What part of the continent(s) create the best fit when trying to piece them back together like a puzzle into the supercontinent Pangaea?

Modern-day species that evolved in isolation share a common ancestor.

What piece of evidence supports Wegener's hypothesis of continental drift?

cone shaped

A major characteristic of a seamount is that it is ________.

latitude

Climate distribution on Earth is primarily controlled by:

a convergent boundary

If you found a line of volcanic peaks a few hundred miles long in which the volcanoes were of mixed ages in no particular order, what probably created them?

a hot spot

If you found a line of volcanic peaks a few hundred miles long in which the volcanoes were progressively older toward one end of the line, what probably created them?

mid-ocean ridges

In the ocean, where are the youngest rocks found?

ocean trenches

Most large earthquakes occur along which of the following?

increases in proportion to the distance.

Moving from an oceanic ridge to an oceanic trench, the thickness of the lithosphere:

Over the last 186 years, the location of Earth's magnetic north pole has moved in a northwesterly direction.

Over the last 186 years, how has the location of Earth's magnetic north pole changed?

declining

Plate convergence begins during which stage of the Wilson Cycle?

divergent/convergent/transform

Plates move apart at __________ boundaries, move together at __________ boundaries, and move side-by-side at __________ boundaries.

A, C, B

Rank the density of the lithosphere at points A, B, and C. Rank from highest density (left) to lowest density (right).

shallow; deep

Spreading centers have ________ earthquakes, while trenches have ________ earthquakes.

The mechanism he proposed for the movement of the continents.

Alfred Wegener's continental drift hypothesis received much hostile criticism and ridicule from the scientific community because of which of the following?

increased; decreased

Based on the Theory of Plate Tectonics, you would expect to find ________ heat flow at the mid-ocean ridge and ________ heat flow at subduction zones when compared to other parts of the crust.

smaller; larger

Based on the map of what the world may look like in 50 million years from now, the Pacific Ocean will become ________ while the Atlantic Ocean will become ________.

the African Plate is essentially stationary with respect to Earth's interior and the thick continental crust acts as a "heat blanket"

Compared to the rest of the planet, an unusually high concentration of hotspots and rifting is located on the continent of Africa. A likely explanation for this is that __________.

moving toward

Complete this statement: Divergence is to moving away as convergence is to _______.

The particle of magnetite would be aligned parallel with Earth's surface at the magnetic Equator, it would be aligned at a diagonal with respect to Earth's surface at the Tropic of Cancer, and it would be pointed directly downward (perpendicular to Earth's surface) at the magnetic North Pole.

How would the alignment of a particle of magnetite differ with respect to the Earth's surface, if it solidified at the magnetic Equator, the Tropic of Cancer, or the magnetic North Pole?