OCE 1001 Ch. 2
Of the following statements about Earth's magnetic field, which is/are true? Choose all that apply.
-The lines of the magnetic force are parallel with Earth's surface at the equator. -The lines of the magnetic force are perpendicular relative to Earth's surface at the magnetic south pole. -The magnetic north pole may reverse so that it is located near the geographic south pole. -The lines of the magnetic force are perpendicular relative to Earth's surface at the magnetic north pole.
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"
The flat top of a guyot or tablemount in deep water is evidence that __________.
the seamount was once at the surface of the ocean, but is now submerged due to plate movement and erosion when it was near sea level
Why does the sea floor have a striped pattern of magnetic anomalies that is symmetric with respect to the mid-ocean ridge? Choose all that apply.
-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.
Which of the following lines of evidence did Alfred Wegener use to support the concept of drifting continents? Choose all that apply.
-the way the shapes of the continents fit together like pieces of a jigsaw puzzle -the distribution of species of fossils -the pattern of similar mountain belts on different continents -evidence of glaciers in areas that are now tropical
If the rate and direction of plate movement remain the same for the next 50 million years, an accurate prediction would then be:
Accretion of the California Terrane onto Alaska
Where would you expect to see alternating bands of rock with different magnetic polarities?
on both sides of the mid-ocean ridge
What did the surface of Earth look like 600 million years ago?
one large continent surrounded by ocean
The study of historical changes of continental shapes and positions is called:
paleogeography.
Which of the following tectonic plates are oceanic? Choose all that apply.
-Nazca Plate -Pacific Plate
When did the great mountain ranges of southern Europe and Asia begin to form?
50 million years ago
Plate convergence begins during which stage of the Wilson Cycle?
Declining
Match the term with the appropriate phrase. Drag the terms on the left to the appropriate blanks on the right. (Terms can be used more than once.)
Island Arc- subduction zone Mid-ocean ridge- spreading center Seafloor magnetic stripes- spreading center Seafloor spreading- spreading center Trench- subduction zone
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.
The Pacific Ocean is an example of the ________ stage of the Wilson Cycle.
declining
Climate distribution on Earth is primarily controlled by:
latitude.
Tectonic plates are pieces of the ________ that float on the more fluid ________ below.
lithosphere; asthenosphere
Ocean basins with continental margins are representative of the ________ stage of the Wilson Cycle.
mature
Which geologic features are associated with divergent boundaries?
mid-ocean ridges and continental rift valleys
When was the Precambrian eon?
prior to 600 million years ago
The Himalaya Mountains are an example of the ________ stage of the Wilson Cycle.
suturing
When will a hot spot volcano become extinct?
when the volcano is carried away from the hot spot by the tectonic plate
Of the following statements about nemataths and volcanic arcs, which is/are true? Choose all that apply.
-In a volcanic arc, any of the volcanoes can be active at any time. -Nemataths and volcanic arcs are both the result of volcanic activity. -Volcanic arcs are associated with convergent plate boundaries.
Of the following statements about ocean crust, which is/are true? Choose all that apply.
-Ocean crust is destroyed at deep sea trenches. -Ocean crust is created at the mid-ocean ridge.
Which of the following statements about the Wilson cycle is/are correct? Choose all that apply.
-The Mediterranean Sea is in the process of closing. -The Pacific Ocean basin is shrinking, and the Atlantic Ocean basin is growing wider. -The embryonic stage begins with continental crust being uplifted and pulled apart.
When did the Appalachian Mountains of North America begin to form?
450 million years ago
How are normal polarity and reverse polarity of Earth's magnetic field different?
A compass points toward the North Pole during normal polarity and to the South Pole during reverse polarity.
In general, what is our best evidence that the orientation of Earth's magnetic field has changed over time?
A record of Earth's magnetic field is recorded in oceanic rocks, which show a clear pattern of changes in Earth's magnetic polarity.
What is a tablemount?
A seamount that grew above sea level, experienced wave erosion, and is now inactive.
Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern.
Aleutian Islands
The first person to advance the idea of mobile continents or continental drift was
Alfred Wegener.
What is the relationship between the mantle and the asthenosphere?
All of the asthenosphere is contained within a larger layer called the mantle.
What is the relationship between the crust and the lithosphere?
All of the crust is contained within a larger layer called the lithosphere.
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.
Which of the following is an example of an oceanic-continental convergent plate boundary?
Andes Mountains
Which of the following mountain ranges are examples of continental arcs?
Andes and Cascades
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.
Which of the following rocks is the most reliable one used to collect information about Earth's magnetic field where and when the rock originated?
Basalt
The first scientist to propose the origin of coral reefs based upon subsidence (sinking) of volcanic islands was
Charles Darwin.
What is the appropriate term for the movement of the orange liquid in the lava lamp animation?
Convection
Which of the following is the main reason that Earth has a magnetic field? Select only one answer.
Convection in the liquid iron-nickel outer core generates a magnetic field.
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.
Iceland is located on what type of plate boundary?
Divergent
What would happen to Earth if ocean floor were created at divergent boundaries at a faster rate than it is destroyed at convergent boundaries?
Earth would increase in volume.
Which of the following statements about Earth's magnetic field is most accurate?
Earth's magnetic field switches polarity at irregular time intervals
Which of the following statements about earthquakes with magnitude greater than 4.0 is most accurate?
Earthquakes with magnitude greater than 4.0 occur in a pattern than correlates closely with plate boundaries.
Which of the following is an example of the embryonic stage of the Wilson Cycle?
East Africa
Which is the correct order of coral reef development near seamounts?
Fringing reef, barrier reef, atoll
The book The History of Ocean Basins, which contained the idea of seafloor spreading, was written by geologist:
Harry Hess.
Which of the following is an example of a nematath?
Hawaiian Islands-Emperor Seamount Chain
Why are ocean basins continually being destroyed and created, rather than simply being redistributed around Earth's surface like continents?
High-density oceanic crust subducts beneath low-density continental crust where plates converge.
When the subcontinent of India drifted northward and collided with Asia, what landform was created?
Himalaya Mountains
Where do coral reefs exist with sea mounts?
In tropical latitudes
Consider the geologic fate of the following seamounts and islands in the Hawaiian Island-Emperor Seamount chain. Assuming conditions remain favorable for coral growth, which would most likely be the next to form an atoll?
Kauai
Which of the following fossils was used as data to help reconstruct Pangea because it was a reptile found in South America and Africa?
Mesosauras
Which of the following was not used as evidence for continental drift?
Paleomagnetic reversals
Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern.
Panamerica
Match the term with the appropriate phrase. Drag the terms on the left to the appropriate blanks on the right to complete the sentences.
Panthalassia-ancient precursor of the Pacific Ocean Pangaea-supercontinent 250 million years ago Rift Valley-depression along a ridge axis Paleomagnetism-study of magnetism over geologic time Subduction zone- sloping area from a trench along a downward moving plate
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.
Wegener used which of the following to provide evidence for continental drift?
Shape of continental margins
What is the relationship between the mantle and the lithosphere?
Some of the mantle is contained within a smaller layer called the lithosphere
Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern.
Stanley Miller
Which of the following statements is true regarding tectonic plates?
Tectonic plates may include both oceanic and continental crust.
Judge the following sentence according to the criteria given below: Andesitic volcanic eruptions are usually less explosive and destructive than basaltic eruptions BECAUSE andesite magma is more viscous than basalt magma and contains a higher gas content.
The assertion is incorrect but the reason is correct.
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.
What is the relationship between the crust and the lithosphere?
The crust is part of the lithosphere.
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.
Which of the following statements is true of the lithosphere?
The lithosphere is composed of the crust and the uppermost portion of the mantle.
Alfred Wegener's continental drift hypothesis received much hostile criticism and ridicule from the scientific community because of which of the following?
The mechanism he proposed for the movement of the continents.
Of the following statements about the age of the ocean crust, which one is true? Select only one answer.
The oldest ocean crust is about 200 million years old and is located near an ocean trench.
What do all plate boundaries have in common? Select only one answer.
They are all associated with zones of earthquakes.
What did the continents that formed during the break-up of the supercontinent 600 million years ago look like?
They were nothing like the continent shapes we see on Earth today.
The Alps are an example of ________ plate boundary.
a continental-continental convergent
Approximately how long does it take for a complete Wilson cycle to occur?
a few hundred million years
What is a volcanic arc?
a row of volcanoes that forms on the overriding plate near a subduction zone
What surface feature would you expect to form if both a hot spot and a tectonic plate are stationary?
a single volcano
What was Pangea?
a supercontinent that formed 300 million years ago
Where is the youngest ocean floor found?
along the crest of mid-ocean ridges
The Mariana Trench is an example of ________ plate boundary.
an oceanic-oceanic convergent
The East Pacific Rise is an example of ________ plate boundary.
an oceanic-oceanic divergent
Which of the following is characteristic of oceanic-continental convergent plate boundaries?
andesitic volcanoes
Where are tectonic plates located?
at Earth's surface
Where do most earthquakes occur?
at plate boundaries
Which type of plate boundary is most closely associated with uplifting continental regions and mountain building?
convergent boundaries
Which type of plate boundary is most closely associated with the formation of new ocean floor?
divergent
The Mid-Atlantic Ridge is an example of
divergent plate boundary.
What are the three types of plate boundaries?
divergent, convergent, and transform
Plates move apart at __________ boundaries, move together at __________ boundaries, and move side by side at __________ boundaries.
divergent/ convergent/ transform
All continents fit together with the least number of overlaps and gaps when the continents are matched along ________.
edges at around 2,000 meters depth
How often does the Earth's magnetic field switch polarity?
every 100,000 to several million years
Coral reefs that initially develop along the margin of an island or continent where environmental conditions are suitable are called:
fringing reefs.
Underwater volcanic peaks that resemble volcanoes on land except that they are flat on top are called ________.
guyots
Which phenomenon can explain the presence of volcanoes in the middle of the Pacific Ocean?
hot spots
Coral reefs_______.
include atolls, barrier, and fringing reefs
Moving from an oceanic ridge to an oceanic trench, the thickness of the lithosphere:
increases in proportion to the distance.
What stage is marked by the creation of a well-formed ocean basin with a mid-ocean ridge in the middle?
mature
The Hawaiian Islands are located where the Pacific plate is:
moving over a hot spot or mantle plume.
Complete this statement: Divergence is to moving away as convergence is to _______.
moving toward
Where in a lava lamp would the density of both materials be equal?
near the middle of the lamp
Chains of extinct volcanoes that are progressively older as one travels away from a hotspot are called ________.
nemataths
Which geologic features are associated with convergent boundaries?
ocean trenches and volcanoes
The steeply-sloping and slower-spreading parts of the mid-ocean ridge are called ________.
oceanic ridges
Fossils of ancient tropical plants are currently found near the poles because the:
plants lived in the tropics, but landmasses have drifted to current locations.
Which process causes the surface geography of Earth to change over time?
plate tectonics
Large volcanoes on the seafloor that are cone-shaped on top because they never reached sea level are called:
seamounts.
Continent-continent convergence occurs in what stage of the Wilson cycle?
suturing
What is meant by the term plate boundary?
the edge of a plate, where two plates meet each other
Frederick Vine and Drummond Matthews determined that new ocean floor was being produced at ocean ridges by examining:
the magnetic pattern of rocks on the seafloor.
Which plate boundary is NOT associated with volcanic eruptions?
transform
What surface feature provides evidence for the location of hot spots?
volcanoes within tectonic plates
