OCE Ch 2

Of the following statements about nemataths and volcanic arcs, which is/are true?

-A nematath is created by a hotspot. -A volcanic arc is associated with a convergent plate boundary. -In a volcanic arc, any of the volcanoes can be active at any time. -In a nematath, the age of the volcanoes progressively decreases as you move closer to the volcanic source. -Nemataths and volcanic arcs are both the result of volcanic activity.

Which of the following are examples of modern-day island arcs? CHOOSE ALL THAT APPLY.

-Aleutian Islands -Mariana Islands

Of the following statements about ocean crust, which is/are true?

-Ocean crust is destroyed at deep sea trenches. -Ocean crust is created at the mid-ocean ridge.

Why does the sea floor have a striped pattern of magnetic anomalies that is symmetric with respect to the mid-ocean ridge?

-The polarity of Earth's magnetic field experiences reversals. -The igneous rock of the ocean floor preserves Earth's existing magnetic field as the rock cools. -The ocean floor is spreading apart, and new sea floor is forming.

In general, where do earthquakes AND volcanic eruptions occur? Choose all that apply.

-divergent plate boundaries -convergent plate boundaries

ow are continental rift magmas and continental arc magmas different?

Continental arc magmas are more viscous than continental rift magmas.

Match the term with the appropriate phrase. mid-ocean ridge

spreading center

Transform boundaries are classified under what type of fault?

strike-slip

Which of the following could cause rock to melt?

-change in composition -decrease in pressure -increase in temperature

Which of the following are common tectonic settings associated with volcanic activity? CHOOSE ALL THAT APPLY.

-continental arcs -continental rifts -island arcs -mantle plumes

celand is located on what type of plate boundary?

Divergent

What type of boundary is represented by the line just to the east of point A?

This is not a plate boundary.

What role do transform boundaries play?

Transform boundaries connect other segments of plate boundaries.

What is the relationship between transform boundaries and mid-ocean ridges?

Transform boundaries connect segments of mid-ocean ridges.

Why are volcanoes NOT found at transform boundaries?

Transform boundaries do not cause changes to the pressure, temperature, or composition of the mantle.

True or False: A rift valley may be associated with divergent plate boundaries.

True

True or False: Deep-sea trenches are found at convergent plate boundaries.

True

True or False: The relatively young age of the seafloor supports the idea that subduction must take place.

True

What is the relationship between continent edges and plate boundaries?

Very few plate boundaries follow the edges of continents.

Where does the water involved in melting at subduction zones come from?

Water contained within minerals in the subducting plate is released during metamorphism.

The East African rift is a divergent plate boundary that is splitting the continent of Africa into two pieces. What will eventually form around this divergent boundary?

an ocean

Which of the following lines of evidence did Alfred Wegener use to support the concept of drifting continents?

-the pattern of similar mountain belts on different continents -evidence of glaciers in areas that are now tropical -the way the shapes of the continents fit together like pieces of a jigsaw puzzle -the distribution of species of fossils

Please identify the word or phrase that does not fit the pattern. A. transform fault B. San Andreas Fault C. oceanic transform fault D. Mendocino Fracture Zone E. Mariana Trench

E

What were the names of the two smaller super continents that formed when Pangaea broke apart?

Laurasia and Gondwanaland

Which of the following statements about tectonic plates is true?

Most tectonic plates contain both oceanic and continental lithosphere.

Climate distribution on Earth is primarily controlled by:

latitude

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

lithosphere; asthenosphere

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

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

Based on paleogeographic records, _____________.

the North Atlantic opened before India separated from Antarctica

What caused the formation of the Himalayas?

the collision of India with Asia

Sea floor spreading along the axis of an oceanic ridge results in symmetrical patterns of all of the following EXCEPT ______________.

the location of subduction zones

Seafloor depth was first determined by what remote sensing technology?

echo sounder

The earthquakes that occur in Southern California generally occur above a _______________.

fault

Coral reefs that initially develop along the margin of an island or continent where environmental conditions are suitable are called:

fringing reefs.

Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from a _______________.

hot spot

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

increases in proportion to the distance.

Where in a lava lamp would the density of both materials be equal?

near the middle of the lamp

What forms at divergent plate boundaries?

new oceanic lithosphere

Where are continental volcanic arcs found?

on the overriding plate near a subduction zone

n general, where do volcanoes form in subduction zones?

on the overriding plate, away form the convergent boundary

_______________ found in the Atlantic Ocean between North America and Europe is composed of dense and relatively young rock.

seafloor crust

Wegener used all the following to provide evidence for continental drift except :

seafloor magnetic pattern.

The slowly increasing distance between South America and Africa is due to ______________.

seafloor spreading

Large volcanoes on the seafloor that are cone-shaped on top because they never reached sea level are called:

seamounts.

Layered ______________ exposed by erosion can be seen when looking at the Grand Canyon in the United States.

sedimentary rock

The extremely deep ocean Marianas Trench is a result of _____________.

subduction

Match the term with the appropriate phrase. trench

subduction zone

The following set of observations describes an actual body of water. Evaluate these statements and determine the evolutionary stage of an ocean basin based upon the following characteristics: -Lacks a mid-ocean ridge -Deep ocean basin is present -Early signs of mountain formation -Volcanic island arc and trench absent

terminal

Which of the following is a present-day example of a continental rift?

the East African rift valley

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

paleogeography.

Match the term with the appropriate phrase. study of magnetism over geologic time

paleomagnetism

The seafloor magnetic pattern is best described as:

parallel to and symmetric about mid-ocean ridges.

What is a mantle plume?

a circular column of magma that rises from deep within Earth

If ocean crust forms at a rate of 10 centimeters per year, how much ocean crust can be created in 20 million years? Select only one answer.

2000 kilometers

Please identify the word or phrase that does not fit the pattern. A. hydrothermal vents B. island arcs C. tall, folded mountain belts D. oceanic trenches E. large volcanoes caused by subduction

A

What is a tablemount?

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

The first person to advance the idea of mobile continents or continental drift was:

Alfred Wegener.

Why does the orange liquid rise when the lava lamp animation is plugged in?

Although both liquids expand when heated, the orange liquid expands more.

What is a seamount?

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

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

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

ow are island arc and continental arc magmas similar?

Both are formed near subduction zones

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

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

True or False: Paleomagnetism confirms that at particular times in the geologic past Earth has had more than one magnetic north pole.

False

True or False: The majority of the world's hotspots are associated with plate boundaries.

False

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

Fringing reef, barrier reef, atoll

Which supercontinent contained Africa and South America?

Gondwanaland

Which of the following is an example of modern-day mantle plume volcanism?

Hawaiian Islands

Where do coral reefs exist with sea mounts

In tropical latitudes

Do fracture zones near transform boundaries play a role in plate motion?

No; fracture zones play no role in plate motion.

How do plates move at divergent plate boundaries?

Plates move apart.

How do plates move at convergent plate boundaries?

Plates move toward one another.

How do plates move at transform plate boundaries?

Plates slide past one another.

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

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

Why is decompression melting common at mid-ocean ridges but not at subduction zones?

Tectonic plates are moving apart at mid-ocean ridges, resulting in a lowering of pressure beneath the ridge. Tectonic plates are moving together at subduction zones, resulting in an increase of pressure under new mountains.

Why did Heezen and Tharp have to do "inspired guessing" when creating their maps of the ocean floor?

There were gaps in the data that were used to make the map because the tracks of the ships collecting the data were widely spaced.

Why is water a necessary component of the melting process in subduction zones?

The addition of water lowers the melting temperature of rock.

What would happen in the lava lamp if the orange liquid were denser at warmer temperatures than the blue/clear liquid shown in the animation?

The blue/clear liquid would rise toward the top when the lamp was turned on, whereas the orange liquid would sink.

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

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

What prompted the first widespread mapping of the ocean floor?

The importance of submarine warfare during World War II

Which properties of a lava lamp are important to remember when modeling convection?

The lava lamp contains two liquids with different densities that do not mix and that expand at different rates when heated.

As Heezen and Tharp interpreted the ocean depth data, they identified what unusual feature that hinted at continental drift?

The oceanic ridges have a cleft, or rift, in the middle rather than a peak.

What would happen to the orange liquid in the lava lamp if heat did NOT conduct out of the top of the lava lamp?

The orange liquid would stay near the top of the lava lamp.

In which direction is the plate moving at point A?

The plate is moving north.

In which direction is the plate moving at point B?

The plate is moving south.

In which direction is the plate moving at point C?

The plate is moving south.

What did the maps of the ocean floor produced by Bruce Heezen and Marie Tharp reveal about seafloor topography?

There are ridges in the middle of the ocean basin floors.

Australia is composed of relatively old and thick ______________.

continental crust

What is the appropriate term for the movement of the orange liquid in the lava lamp animation?

convection

Which two processes commonly generate magma?

decompression melting and wet melting (the addition of volatiles)

The Mid-Atlantic Ridge is an example of a:

divergent plate boundary.

What is peridotite?

the rock making up the mantle

What was Panthalassa?

the single ocean that existed after the Pangaean supercontinent formed

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

uplifted mountain ranges

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

volcanic island arcs

Which of the following often forms after continental rifting?

a new ocean basin

What was the Tethys Sea?

a piece of the Panthalassa Ocean that existed after the Pangaean supercontinent formed

What was Pangaea?

a supercontinent that began to break apart about 200 million years ago