OCE1001 ch 2 – Flashcards

question
A(n)____ occurs where two plates converge, and the denser plate is subducted
answer
Oceanic-continental convergence
question
A(n) ____ occurs where two plates of the same composition converge, resulting in the older, denser plate being subducted
answer
Oceanic-oceanic convergence
question
A(n) ____ occurs where two plates of the same composition converge, resulting in neither plate being subducted
answer
Continental-continental convergence
question
India seperated from Antartica _____
answer
120 mya
question
The North Atlantic Ocean opened _____
answer
180 mya
question
The continents came together as Pangaea ______
answer
300 mya
question
North America lay on the equator ________
answer
540 mya
question
Which type of plate boundary is most closely associated with the formation of new ocean floor?
answer
divergent
question
Which of the following statements about Earth's magnetic field is most accurate?
answer
Earth's magentic field switches polarity at irregular time intervals
question
How often does the Earth's magnetic field switch polarity
answer
every 100,000 to several million years
question
How are normal polarity and reverse polarity of Earth's magnetic field different?
answer
A compass points towards the North Pole during normal polarity and the South Pole during reverse polarity
question
In general, what is our best evidence that the orientation of Earth's magentic field has changed over time?
answer
A record of Earth's magnetic field is recorded in oceanic rocks, which shows a clear pattern of changes in Earth's magnetic field
question
Where would you expect to see alternating bands of rock with different magnetic polarities
answer
on both sounds of the mid-ocean ridge
question
The slowly increasing distance between South America and Africa is due to
answer
Seafloor spreading
question
Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from a
answer
hot spot
question
Layered ____ exposed by erosion can be seen when looking at the Grand Caynon in the United States
answer
sedimentary rock
question
Australia is composed of relatively old and thick
answer
continental crust
question
The extremely deep ocean Mariana's Trench is a result of
answer
subduction
question
____ found in the Atlantic Ocean between North America and Europe is composed of dense and relatively young rock
answer
Seafloor crust
question
The earthquakes that occur in Southern California generally occur above a
answer
fault
question
Evidence for continental drift includes:
answer
The distribution of organisms, matching sequences of rocks and mountain chains, past glacial activity, and the fit of the continents
question
Fossils of ancient polar plants are currently found near the equator because the:
answer
plants lived near the poles, but landmases have drifted to current locations
question
Climate distribution on Earth is primarily controlled by
answer
latitude
question
Regarding glacial ages, why is it unlikely that the entire world was covered by ice 300 mya?
answer
Coal deposits from the same geological age are now present in North America and Europe, which formed the remains of vast tropical swamps
question
Earthquakes can only occur in the ______
answer
lithosphere
question
The seafloor magnetic pattern is best described as
answer
parallel to and symetric about mid ocean ridges
question
Tectonic plates are pieces of the ________ that float on the more fluid ________ below
answer
lithosphere; asthenosphere
question
Describe seafloor spreading and why it is an important piece of evidence in support of plate tectonics
answer
Captain Hess suggested that new ocean crust was created at the mid-oceanic ridges and dispearred back into deep Earth at the trenches near the edge of ocean basins. This was an important piece of evidence in support of plate tectonics because it provided a mechanism for continental and oceanic plate motion
question
When will magnma rise to the Earth's surface?
answer
when the magma is less dense than adjacent rock
question
In general, when will melted rock in the mantle rise?
answer
almost always
question
How are felsic magmas formed?
answer
Heat from the mantle melts part of the lower crust
question
In general, why does Earth's crust sit on top of the mantle?
answer
earth's crust is less dense than the mantle
question
How do mafic volcanic rocks get to Earth's surface?
answer
Pressure from overlying crust forces mantle magmas through cracks to Earth's surface. These magmas erupt out of volcanoes, cool and solidy into rock1
question
Where are tectonic plates located?
answer
At Earth's surface
question
What are the three types of plate boundaries?
answer
Divergent, convergent and transform
question
Which of the following statements about earthquakes with magnitude greater than 4.0 is most accurate?
answer
Earthquake with a magnitude greater than a 4.0 occur in a pattern that correlates closely with plate boundaries
question
Which plate boundary is NOT associated with volcanic eruptions?
answer
Transform
question
Which phenomenon can explain the presence of volcanoes in the middle of the Pacific Ocean?
answer
hotspots
question
Which type of plate boundary is most closely associated with uplifting continental regions and mountain building?
answer
Convergent boundaries
question
What is convection
answer
A cycle of moving material formed by the rise of less-dense material and sinking of denser material
question
What is responsible for most tectonic plate action?
answer
Forces at subduction zones
question
What is the relationship between temperature and denisty?
answer
In general, warmer materials are less dense and colder materials are denser
question
Which of the following best characterizes upwelling in the asthenosphere
answer
diffuse
question
What is a plume
answer
a zone of upwelling material originating at the outer-core mantle boundary
question
What features at the surfaces provide evidence of plumes?
answer
Hot spots
question
Which of the following are types of volcanoes?
answer
Cinder cone, shield volcano, composite volcano
question
What information do geologists use to classify volcanoes?
answer
shape and type of deposits
question
Cinder cones are made of________.
answer
Pyroclastic deposits
question
In general, how often do most cinder cones erupt?
answer
once
question
What are shield volcanoes generally made of?
answer
Basalt flows
question
What is the range of shield volcano height?
answer
300 to 10000 m
question
What are composite volcanoes made of?
answer
Basalt flows, pryroclastic volcanos
question
Why are shield volcanoes wider than composite volcanoes?
answer
The lava that flows out of shield volcanoes is more fluid than the lava that flows out of composite volcanoes.
question
What type of volcanoes are the highest?
answer
Shield volcanoes
question
What is the range of dome complex height?
answer
500 to 2000 m
question
The Mid Atlantic Ridge is an example of a
answer
divergent plate boundary
question
Which of the following is characteristic of oceanic-continental convergent plate boundaries?
answer
andesitic volcanoes
question
Which of the following is characteristic of continental-continental convergent plate boundaries?
answer
uplifted mountain ranges
question
Deep-sea trenches are found at convergent plate boundaries
answer
True
question
Water depth decreases as you move away from the mid ocean ridge
answer
False
question
Convergent plate boundaries occur when tectonic plates move in opposite directions.
answer
False
question
Do most lithospheric plates contain both oceanic- and continental-type crust?
answer
Yes, most contain both oceanic and contintenal type crust
question
What is the relationship between the crust and the lithosphere?
answer
All of the crust is contained within a larger layer called the lithosphere
question
What is the relationship between the mantle and the lithosphere?
answer
Some of the mantle is contained within a smaller layer called the lithosphere
question
What is the relationship between the mantle and the asthenosphere?
answer
All of the asthenosphere is contained within a larger layer called the mantle
question
What surface feature provides evidence for the location of hot spots?
answer
Volcanoes within tectonic plates
question
When will a hot spot volcano become extinct?
answer
When the volcano is carried away from the hot spot by the tectonic plate
question
What surface feature would you expect to form if both a hot spot and a tectonic plate are stationary?
answer
A single volcano
question
What is a seamount
answer
An active volcano that occurs along the crest of the mid ocean ridge
question
What is a tablemount
answer
A seamount that grew above sea level, experienced wave erosion and is now inactive
question
Where do coarl reefs exist within seamounts
answer
In tropical latitudes
question
Which of the following statements about coral reefs and seamounts is most accurate?
answer
Coral reefs at the ocean surface grow away from seamouts overtime
question
Why do coral reefs grow away from seamounts over time?
answer
Seamounts subside as tectonic plates move. Coral reefs grow away from the seamounts in order to stay near the sunlight
question
What is the difference between a barrier reef and an atoll?
answer
Barrier reefs surround an inactive volcano emerging above sea level, while atolls surround the previous location of a submerged volcano.
question
Which is the correct order of coral reef development near seamounts?
answer
Fringing reef, barrier reef, atoll
question
Iceland is located on what type of plate boundaray
answer
Divergent
question
The Hawaiian Islands are located where the Pacific plate is:
answer
Moving over a hot spot or mantle plume
question
volcanoes on the seafloor that are flat-topped because of wave erosion are called:
answer
tablemounts
question
The first scientist to propose the origin of coral reefs based upon subsidence (sinking) of volcanic islands was:
answer
Charles Darwin
question
Areas of intense volcanic activity that remain in more or less the same location over long periods of geologic time and are unrelated to plate boundaries are called hotspots.
answer
True
question
The majority of the world's hotspots are associated with plate boundaries.
answer
False
question
Charles Darwin was the first person to propose a hypothesis on the origin of coral reefs.
answer
True
question
How is the age distribution pattern of the Hawaiian Islands-Emperor Seamount chain explained by the position of the Hawaiian hot spot
answer
The volcanoes here get progessively odler as one heads NW from Hawaii. These age relationships suggest that the Pacific plate has been steadily moving NW, while underlying mantle plume has remained relatively stationary
question
How can plate tectonics be used to help explain the difference between a seamount and a tablemount?
answer
A seamount is a volcano with a cone-shaped top, whereas a tablemount is a volcano with a flattened top. Though both of these features originate at the crest (and topographic high) of the mid-ocean ridge, a tablemount has been subject to wave erosion when it rises above sea level. When the crust containing the tablemount is pushed away from the crest (and therefore onto a topographically lower position), or is moved away from a hot spot, it is re-submerged with its flat top
question
The study of historical changes of continental shapes and positions is called
answer
paleogeography
question
Loihi is
answer
the neweste Hawaiian volcano
question
A researcher interested in the vertical zonation of oceanic lithosphere would want to study __________.
answer
Ophiolites
question
The wilson cycle uses plate tectonic processes to show the life cycle of ocean basins during their growth, formation, and destruction over gelogical time
answer
True
question
Of the following statements about Earth's magnetic field, which is/are true?
answer
The magnetic field is oriented vertical relative to Earth's surface at the south magnetic pole
question
Of the following statements about ocean crust, which is/are true
answer
Ocean crust is destroyed at deep sea trenches
question
What do all plate boundaries have in common?
answer
They are all associated with zones of Earthquakes
question
Of the following statements about nemataths and volcanic arcs, which is/are true?
answer
In a volcanic arc, any of the volcanoes can be active at any time
question
What was the main reason scientists objected to Alfred Wegners idea of continental drift?
answer
Wegener's proposed mechanism for movement was thought to violate the laws of physics
question
As a tool, the modern evidence from paleomagnetism has helped support plate tectonics by showing that
answer
magnetic sea floor "stripes" are symmetric with respect to the mid ocean ridge
question
The East Pacific ridge is associated with what type of boundary?
answer
Divergent
question
How is it that the Ocean floor is much younger than the ocean itself
answer
The ocean floor keeps regenerating itself
question
plate boundaries where new oceanic crust is being added are called
answer
divergent boundaries
question
The faster the rate of spreading at the mid ocean ridge or rise, the ____ the underwater volcanic range
answer
broader (wider)
question
Most lithospheric plates contain both oceanic and continental crust
answer
True
question
The Hawaiian islands are associated with which type of plate boundary
answer
they are not associated with any type of plate boundary
question
In general, where would the youngest ocean floor be found
answer
at the mid ocean ridge
question
What happens when an oceanic and continental plate converge>
answer
The oceanic plate will be subducted
question
What happens when two continental plates conver
answer
Neither subducts; instead a mntn range forms
question
Your job is to locate the worlds plate boundaries. To do this you may use only one map. The best map to choose for this job is a map that shows the worldwide locations of
answer
earthquakes
question
Which of the following is associated with a subduction zone
answer
a volcanic arc
question
How much wider is the Atlantic Ocean today than when Christopher Columbus sailed? Assume that the Atlantic Ocean is getting wider at a rate of 3 centimeters per year (about 1 inch). (Round off the dates to the nearest century to make the calculation simpler.)
answer
15 m (49 ft)
question
An ocean trench is what type of boundary
answer
convergent
question
The San Andreas Fault is associated with which type of plate boundary?
answer
transform
question
Where would you not expect to find significant volcano activity
answer
continental collision zones
question
Which of the following tropical islands would likely be the youngest?
answer
Tropical island with a fringing reef
question
What best describes the tectonic setting of the Cascade mtns of the Pacific NW
answer
subduction zone
question
Overall the Atlantic Ocean is ____ and the Pacific is _____
answer
growing; shrinking
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question
A(n)____ occurs where two plates converge, and the denser plate is subducted
answer
Oceanic-continental convergence
question
A(n) ____ occurs where two plates of the same composition converge, resulting in the older, denser plate being subducted
answer
Oceanic-oceanic convergence
question
A(n) ____ occurs where two plates of the same composition converge, resulting in neither plate being subducted
answer
Continental-continental convergence
question
India seperated from Antartica _____
answer
120 mya
question
The North Atlantic Ocean opened _____
answer
180 mya
question
The continents came together as Pangaea ______
answer
300 mya
question
North America lay on the equator ________
answer
540 mya
question
Which type of plate boundary is most closely associated with the formation of new ocean floor?
answer
divergent
question
Which of the following statements about Earth's magnetic field is most accurate?
answer
Earth's magentic field switches polarity at irregular time intervals
question
How often does the Earth's magnetic field switch polarity
answer
every 100,000 to several million years
question
How are normal polarity and reverse polarity of Earth's magnetic field different?
answer
A compass points towards the North Pole during normal polarity and the South Pole during reverse polarity
question
In general, what is our best evidence that the orientation of Earth's magentic field has changed over time?
answer
A record of Earth's magnetic field is recorded in oceanic rocks, which shows a clear pattern of changes in Earth's magnetic field
question
Where would you expect to see alternating bands of rock with different magnetic polarities
answer
on both sounds of the mid-ocean ridge
question
The slowly increasing distance between South America and Africa is due to
answer
Seafloor spreading
question
Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from a
answer
hot spot
question
Layered ____ exposed by erosion can be seen when looking at the Grand Caynon in the United States
answer
sedimentary rock
question
Australia is composed of relatively old and thick
answer
continental crust
question
The extremely deep ocean Mariana's Trench is a result of
answer
subduction
question
____ found in the Atlantic Ocean between North America and Europe is composed of dense and relatively young rock
answer
Seafloor crust
question
The earthquakes that occur in Southern California generally occur above a
answer
fault
question
Evidence for continental drift includes:
answer
The distribution of organisms, matching sequences of rocks and mountain chains, past glacial activity, and the fit of the continents
question
Fossils of ancient polar plants are currently found near the equator because the:
answer
plants lived near the poles, but landmases have drifted to current locations
question
Climate distribution on Earth is primarily controlled by
answer
latitude
question
Regarding glacial ages, why is it unlikely that the entire world was covered by ice 300 mya?
answer
Coal deposits from the same geological age are now present in North America and Europe, which formed the remains of vast tropical swamps
question
Earthquakes can only occur in the ______
answer
lithosphere
question
The seafloor magnetic pattern is best described as
answer
parallel to and symetric about mid ocean ridges
question
Tectonic plates are pieces of the ________ that float on the more fluid ________ below
answer
lithosphere; asthenosphere
question
Describe seafloor spreading and why it is an important piece of evidence in support of plate tectonics
answer
Captain Hess suggested that new ocean crust was created at the mid-oceanic ridges and dispearred back into deep Earth at the trenches near the edge of ocean basins. This was an important piece of evidence in support of plate tectonics because it provided a mechanism for continental and oceanic plate motion
question
When will magnma rise to the Earth's surface?
answer
when the magma is less dense than adjacent rock
question
In general, when will melted rock in the mantle rise?
answer
almost always
question
How are felsic magmas formed?
answer
Heat from the mantle melts part of the lower crust
question
In general, why does Earth's crust sit on top of the mantle?
answer
earth's crust is less dense than the mantle
question
How do mafic volcanic rocks get to Earth's surface?
answer
Pressure from overlying crust forces mantle magmas through cracks to Earth's surface. These magmas erupt out of volcanoes, cool and solidy into rock1
question
Where are tectonic plates located?
answer
At Earth's surface
question
What are the three types of plate boundaries?
answer
Divergent, convergent and transform
question
Which of the following statements about earthquakes with magnitude greater than 4.0 is most accurate?
answer
Earthquake with a magnitude greater than a 4.0 occur in a pattern that correlates closely with plate boundaries
question
Which plate boundary is NOT associated with volcanic eruptions?
answer
Transform
question
Which phenomenon can explain the presence of volcanoes in the middle of the Pacific Ocean?
answer
hotspots
question
Which type of plate boundary is most closely associated with uplifting continental regions and mountain building?
answer
Convergent boundaries
question
What is convection
answer
A cycle of moving material formed by the rise of less-dense material and sinking of denser material
question
What is responsible for most tectonic plate action?
answer
Forces at subduction zones
question
What is the relationship between temperature and denisty?
answer
In general, warmer materials are less dense and colder materials are denser
question
Which of the following best characterizes upwelling in the asthenosphere
answer
diffuse
question
What is a plume
answer
a zone of upwelling material originating at the outer-core mantle boundary
question
What features at the surfaces provide evidence of plumes?
answer
Hot spots
question
Which of the following are types of volcanoes?
answer
Cinder cone, shield volcano, composite volcano
question
What information do geologists use to classify volcanoes?
answer
shape and type of deposits
question
Cinder cones are made of________.
answer
Pyroclastic deposits
question
In general, how often do most cinder cones erupt?
answer
once
question
What are shield volcanoes generally made of?
answer
Basalt flows
question
What is the range of shield volcano height?
answer
300 to 10000 m
question
What are composite volcanoes made of?
answer
Basalt flows, pryroclastic volcanos
question
Why are shield volcanoes wider than composite volcanoes?
answer
The lava that flows out of shield volcanoes is more fluid than the lava that flows out of composite volcanoes.
question
What type of volcanoes are the highest?
answer
Shield volcanoes
question
What is the range of dome complex height?
answer
500 to 2000 m
question
The Mid Atlantic Ridge is an example of a
answer
divergent plate boundary
question
Which of the following is characteristic of oceanic-continental convergent plate boundaries?
answer
andesitic volcanoes
question
Which of the following is characteristic of continental-continental convergent plate boundaries?
answer
uplifted mountain ranges
question
Deep-sea trenches are found at convergent plate boundaries
answer
True
question
Water depth decreases as you move away from the mid ocean ridge
answer
False
question
Convergent plate boundaries occur when tectonic plates move in opposite directions.
answer
False
question
Do most lithospheric plates contain both oceanic- and continental-type crust?
answer
Yes, most contain both oceanic and contintenal type crust
question
What is the relationship between the crust and the lithosphere?
answer
All of the crust is contained within a larger layer called the lithosphere
question
What is the relationship between the mantle and the lithosphere?
answer
Some of the mantle is contained within a smaller layer called the lithosphere
question
What is the relationship between the mantle and the asthenosphere?
answer
All of the asthenosphere is contained within a larger layer called the mantle
question
What surface feature provides evidence for the location of hot spots?
answer
Volcanoes within tectonic plates
question
When will a hot spot volcano become extinct?
answer
When the volcano is carried away from the hot spot by the tectonic plate
question
What surface feature would you expect to form if both a hot spot and a tectonic plate are stationary?
answer
A single volcano
question
What is a seamount
answer
An active volcano that occurs along the crest of the mid ocean ridge
question
What is a tablemount
answer
A seamount that grew above sea level, experienced wave erosion and is now inactive
question
Where do coarl reefs exist within seamounts
answer
In tropical latitudes
question
Which of the following statements about coral reefs and seamounts is most accurate?
answer
Coral reefs at the ocean surface grow away from seamouts overtime
question
Why do coral reefs grow away from seamounts over time?
answer
Seamounts subside as tectonic plates move. Coral reefs grow away from the seamounts in order to stay near the sunlight
question
What is the difference between a barrier reef and an atoll?
answer
Barrier reefs surround an inactive volcano emerging above sea level, while atolls surround the previous location of a submerged volcano.
question
Which is the correct order of coral reef development near seamounts?
answer
Fringing reef, barrier reef, atoll
question
Iceland is located on what type of plate boundaray
answer
Divergent
question
The Hawaiian Islands are located where the Pacific plate is:
answer
Moving over a hot spot or mantle plume
question
volcanoes on the seafloor that are flat-topped because of wave erosion are called:
answer
tablemounts
question
The first scientist to propose the origin of coral reefs based upon subsidence (sinking) of volcanic islands was:
answer
Charles Darwin
question
Areas of intense volcanic activity that remain in more or less the same location over long periods of geologic time and are unrelated to plate boundaries are called hotspots.
answer
True
question
The majority of the world's hotspots are associated with plate boundaries.
answer
False
question
Charles Darwin was the first person to propose a hypothesis on the origin of coral reefs.
answer
True
question
How is the age distribution pattern of the Hawaiian Islands-Emperor Seamount chain explained by the position of the Hawaiian hot spot
answer
The volcanoes here get progessively odler as one heads NW from Hawaii. These age relationships suggest that the Pacific plate has been steadily moving NW, while underlying mantle plume has remained relatively stationary
question
How can plate tectonics be used to help explain the difference between a seamount and a tablemount?
answer
A seamount is a volcano with a cone-shaped top, whereas a tablemount is a volcano with a flattened top. Though both of these features originate at the crest (and topographic high) of the mid-ocean ridge, a tablemount has been subject to wave erosion when it rises above sea level. When the crust containing the tablemount is pushed away from the crest (and therefore onto a topographically lower position), or is moved away from a hot spot, it is re-submerged with its flat top
question
The study of historical changes of continental shapes and positions is called
answer
paleogeography
question
Loihi is
answer
the neweste Hawaiian volcano
question
A researcher interested in the vertical zonation of oceanic lithosphere would want to study __________.
answer
Ophiolites
question
The wilson cycle uses plate tectonic processes to show the life cycle of ocean basins during their growth, formation, and destruction over gelogical time
answer
True
question
Of the following statements about Earth's magnetic field, which is/are true?
answer
The magnetic field is oriented vertical relative to Earth's surface at the south magnetic pole
question
Of the following statements about ocean crust, which is/are true
answer
Ocean crust is destroyed at deep sea trenches
question
What do all plate boundaries have in common?
answer
They are all associated with zones of Earthquakes
question
Of the following statements about nemataths and volcanic arcs, which is/are true?
answer
In a volcanic arc, any of the volcanoes can be active at any time
question
What was the main reason scientists objected to Alfred Wegners idea of continental drift?
answer
Wegener's proposed mechanism for movement was thought to violate the laws of physics
question
As a tool, the modern evidence from paleomagnetism has helped support plate tectonics by showing that
answer
magnetic sea floor "stripes" are symmetric with respect to the mid ocean ridge
question
The East Pacific ridge is associated with what type of boundary?
answer
Divergent
question
How is it that the Ocean floor is much younger than the ocean itself
answer
The ocean floor keeps regenerating itself
question
plate boundaries where new oceanic crust is being added are called
answer
divergent boundaries
question
The faster the rate of spreading at the mid ocean ridge or rise, the ____ the underwater volcanic range
answer
broader (wider)
question
Most lithospheric plates contain both oceanic and continental crust
answer
True
question
The Hawaiian islands are associated with which type of plate boundary
answer
they are not associated with any type of plate boundary
question
In general, where would the youngest ocean floor be found
answer
at the mid ocean ridge
question
What happens when an oceanic and continental plate converge>
answer
The oceanic plate will be subducted
question
What happens when two continental plates conver
answer
Neither subducts; instead a mntn range forms
question
Your job is to locate the worlds plate boundaries. To do this you may use only one map. The best map to choose for this job is a map that shows the worldwide locations of
answer
earthquakes
question
Which of the following is associated with a subduction zone
answer
a volcanic arc
question
How much wider is the Atlantic Ocean today than when Christopher Columbus sailed? Assume that the Atlantic Ocean is getting wider at a rate of 3 centimeters per year (about 1 inch). (Round off the dates to the nearest century to make the calculation simpler.)
answer
15 m (49 ft)
question
An ocean trench is what type of boundary
answer
convergent
question
The San Andreas Fault is associated with which type of plate boundary?
answer
transform
question
Where would you not expect to find significant volcano activity
answer
continental collision zones
question
Which of the following tropical islands would likely be the youngest?
answer
Tropical island with a fringing reef
question
What best describes the tectonic setting of the Cascade mtns of the Pacific NW
answer
subduction zone
question
Overall the Atlantic Ocean is ____ and the Pacific is _____
answer
growing; shrinking
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