Related Essays

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/390

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

390 Cards in this Set

  • Front
  • Back
What starts the terrestrial cycle?
Rainfall
What percentage of the Earth is covered by seawater?
71%
What rock records the history of the climate?
Sedimentary rock
What are the two types of weathering?
Chemical and Mechanical
What is weathering?
The alteration of rocks or minerals at Earth's surface
What do Sauropods look like?
Long neck and tail
What do Theropods look like?
bipedal
What are the two main groups of the Sauriscian dinosaur?
Sauropods and Theropods
Describe a Sauriscian hip
The pubis juts forward
Describe the Ornithischian hip
The pubis moves forward and backwards
What is the greatest identifying feature of a dinosaur?
The elongated crest on the humerus
What are the three major Ornithischian groups?
Thereophoran, Ornithodods, and Ceratopsians
True or False the Terasaurus is a dinsoaur?
False
What causes the greatest impact on Earth's surface?
The Fluvial systems (moving water)
Define a Delta
Where a stream or river meets the ocean
Forces that act on a Delta
DEPOSITION
Waves
Tides
Longshore Drift
How are huge U-shaped valleys formed?
From glaciers
How does a river cut through a valley?
It carries larger sediment and pounds it against the rock repeatedly until it is warn away.
How does a river get wider?
Mass wasting
How does a river get longer?
Headward erosion
What does a wave do?
Moves in an orbital motion. Powered by wind. They transport energy to the next wave.
Explain tides
1/2 Meter flux due to the gravitational pull of the moon.
How can granite be changed into rubble?
Its not stable at Earth's surface along with the natural acid in water. Its Feldspar turns to clay
What is the most common form of chemical erosion?
Acidic water
Name the 4 most common forms of Mechanical Weathering
Glaciers
Tides
Ice wedging
Spalling
What is a Water Table?
The level at which the groundwater pressure is equal to atmospheric pressure.
What happens when a hole is drilled into a confined aquaphor?
Water will spring forth
Define Caves
Dissolved limestone from acidic water in humid areas
Define a Cliff
Dissolved limestone from acidic water in an arid area
What is an explosive water table at ground level?
A marsh, lake, swamp, etc.
What is an example of Mass Wasting?
A landslide
A landslide is most likely to occur if the land is made of what mineral?
Shale because it is unstable
What are the two main causes of landslides?
Deforestation
and heavy rainfall
What are the coordinates of a low rainfall area and is it high or low pressure?
30° N and 30° S. It is high pressure
What are the coordinates of a high rainfall area and is it high or low pressure?
60° N and 60° S. It is low pressure
Where do reefs grow?
in clear, shallow and warm water
What is the number one cause of erosion in deserts and why?
Running water because there is no binding vegetation
What is another unstable mineral similar to Shale?
Mudstone
What does soil form from?
Mechanical and Chemical weathering
Organisms: bugs, plants, etc.
Desert dust
What leads to faster erosion?
Increased temperatures
Where does the largest amount of soil form?
At equatorial regions (Hot and Humid), but it is very non nutritious soil
Where does the least amount of soil form?
Near the poles (Cold and Dry)
Why is the soil near the equator red?
Because it forms from iron oxides which do nothing for the nutrients
Earth's climate system is driven by what?
Solar heat and the interactions of the oceans, the atmosphere, and their circulation patterns.
What is the atmosphere and what is it composed of?
It is the gasses that envelope the Earth. It consists mostly of nitrogen and oxygen
What does Earth's ocean consists of?
Liquid water, capped at the poles with sea ice. The most important dissolved constituents in seawater are salt (NaCl) and calcium carbonate (CaCO3).
What is the circulation of the oceans driven by?
By wind, by seawater density differences (caused by variations in salinity and temperature), and by coastal upwelling.
Global climate change can be caused by what?
Changes in solar radiation intensity, volcanism, the development of new mountain belts, changes in the composition of the atmosphere (CO2 content), and the tectonic position of the continents.
Concerns about global warming are based on what?
Increases in atmospheric carbon dioxide caused by the use of fossil fuels.
What is the source of energy that "fuels" motion in the ocean-atmosphere system?
Solar energy
In global atmospheric circulation, dry cool air descends in the _____ and moist warm air ascends in the _____.
Subtropical high pressure belts, equatorial regions
Which of the following statements about water in Earth's atmosphere is INCORRECT?
Warm air holds less water vapor than cold.
Warm surface ocean currents that flow north moderate the climate of what region?
Northern Europe
Which gas makes up the greatest percent of Earth's atmosphere?
Nitrogen (N2)
The atmosphere is divided into several layers based on temperature gradients. In order upward, they are:
troposphere, stratosphere, mesosphere, thermosphere.
Much carbon dioxide was removed from Earth's original atmosphere by
forming calcite (CaCO3).
The stratification of the ocean into an upper and lower layer is very stable. Why?
The lower layer is too dense to mix with the upper layer
Which statement is true about the salinity of the ocean?
Salinity differences help drive the circulation of seawater.
____________ is the state of the atmosphere at any moment in time, while ____________ describes the average atmospheric conditions over a long period of time.
Weather, climate
What is the general term for the blanket of loose rock debris that covers large areas of Earth's surface?
Regolith
Ice wedging is important in preparing for chemical weathering because it
Enlarges fractures and cracks, thereby increasing the surface area of the rock.
Ice wedging would be most effective in
Areas where freezing and thawing occur many times a year.
Which of the following changes takes place during the chemical weathering of granite?
The amount of clay increases and feldspar decreases.
Joints aid chemical weathering by
Providing passageways for water and gases.
Increasing the surface area exposed to weathering agents.
Which of the following minerals most resists chemical weathering?
quartz
Which of the following rock forming minerals weathers to form most of the clay found in soils and regolith?
feldspar
The iron minerals hematite and limonite result from the chemical weathering of iron-rich minerals by the process of
oxidation
Which of the following common rocks would be most susceptible to weathering?
limestone
Which of the following is NOT a type of physical weathering?
conversion of feldspar minerals to clay and soluble material
Which types of mass movement is most universal, regardless of terrain, rock type, or climate?
Creep
What is NOT a major factor influencing mass movement?
Angle of decompose
Which of the following types of mass movement is generally rapid?
Debris flow
Where is solifluction common?
On mountainous slopes of northern Alaska.
Which of the following would be most subject to landsliding (assume slope angle and climate are the same)?
shale
Where are Lahars are commonly produced?
On the flanks of the volcano Pinatubo in the Philippines.
Mass movement can occur
In stream valleys, along mountain fronts, at sea cliffs.
Which types of mass wasting are all predominantly rapid?
debris flows, rockslides, lahars
The stability of a mass of slope material can be reduced by
Removing material from the lower part of the slope.
Increasing the steepness of the slope.
Adding weight to the material of the slope.
The mineralized vein cuts through a series of mica schists. If you find fragments of mineralized rock on the hillside, where should you look for the rest of the vein?
Just above the highest fragment that was found in the regolith
Which feature is NOT commonly associated with a braided stream?
Potholes
Building of the Aswan High Dam on Egypt's Nile River has caused
Increased soil salinity downstream on the floodplain or delta.
A stream transports its sediment load
by what means?
In suspension.
By traction.
In solution.
One of the major ways in which urbanization affects a river system is...
Increased rate of runoff.
Point bars along a meandering stream are deposited where?
On the inside of the meanders
The longitudinal profile of a stream at equilibrium is...
Steepest in the headwaters.
Nearly flat where it enters the sea.
A smooth curve.
A river and valley system evolves through
Downcutting.
Slope retreat.
Headward erosion.
The lowest level to which a stream can erode its channel is called the stream
base level.
Stream terraces form in alluvial valleys when
The stream erodes through previously deposited alluvium.
Out of the 3 Subdivisions of the Fluvial system (The Tree Symbol), which is in charge of transport?
The center subdivision
Wave action domination is characterized by what?
Lagoons, few marshes, and multiple rivers
Fluvial Domination is characterized by what?
Multiple rivers leading out to the ocean with sediment deposits
Tidal Force Domination is characterized by what?
Few marshes, no lagoons, some rivers.
What does a combination of Fluvial, Tide, and wave action domination look like?
Multiple rivers, marshes along the shoreline and sandbars.
The ability of a porous solid to transmit a fluid is called
permeability
Which of the following rocks is known to have low permeability?
shale
Which of the following would have the greatest permeability?
A sequence of vesicular basalt flows
For an unconfined aquifer, what is the water table?
The upper limit at which pore space in the rock is completely saturated with water.
What is the most important dissolution reagent in groundwater?
H2SO4 (sulfuric acid)
HCl (hydrochloric acid)
NaOH (sodium hydroxide)
NH3OH (ammonium hydroxide)
If a well is drilled to a depth of 25 m at a place where the water table is 20 m below the surface, how many meters of water will be in the well?
5 m
Thermal springs and geysers commonly form in the areas listed below EXCEPT for regions
In the interior of small plates.
In order to form, all geysers must have a
Relatively shallow body of hot rocks. System of irregular fracture extending downward from the surface.
Relatively large and constant supply of groundwater.
Good examples of karst topography can be found in
Kentucky.
Florida.
Southern China.
Excessive pumping of a well causes
A cone of depression.
The local water table.
May cause saltwater invasion in coastal areas.
The growth of a cave system (with multiple fractures) was probably controlled by fractures.
True
The best explanation for the origin of the elongated and rounded hills in the aerial photograph of Puerto Rico is
Groundwater erosion
Water feature makes a running well?
If it does not break the Pentiometric Surface
What do areas look like that have experienced pronounced groundwater erosion?
High light colored areas and larger blue areas.
If the front of an active glacier is observed to be stationary, we can infer that the ice in the glacier is
Melting as fast as it moves.
Where are large continental glaciers found today?
In Greenland and Iceland
Glaciers erode mainly by
Plucking and abrasion
Lateral moraines of a valley glacier are composed principally of rock debris
Derived from the weathering of the valley walls.
Kettles result from
Melting of large ice blocks. They are a depression
Several islands and hills in the Boston, Massachusetts area are elliptical and elongated in a north-south direction. Till is common in the area. These hills are most likely
Drumlins
Which of the following glacial deposits is a heterogeneous mixture of unstratified fragments?
Ground moraine
In North America, the southern limit of the Pleistocene continental ice sheet is marked by the present location of what?
The Missouri and Ohio Rivers
The basins of the Great Lakes were formed by
The erosion of nonresistant rocks by a lobe of glacial ice that flowed into lowlands
Periods of glaciation have been documented in
Precambrian Eon.
During much of the Pleistocene Epoch.
The end of the Paleozoic Era.
Where does a Glacier experience stress?
The points where the rock on a hill is the highest
Define a Kettle
A shallow, sediment-filled body of water formed by retreating glaciers or draining floodwaters.
Define a Drumlin
An elongated whale-shaped hill formed by glacial action. Its long axis is parallel with the movement of the ice
Define a Cirque
An amphitheatre-like valley head. A concave area formed at the head of a valley glacier by erosion.
Define an Esker
An esker is a long winding ridge of stratified sand and gravel, examples of which occur in glaciated and formerly glaciated regions of Europe and North America.
Define Karst Topography
Karst topography is a landscape shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite.
Define a Braided Stream
A network of small channels that intersect and create small temporary islands.
Define a Lahar
A type of mudflow or landslide composed of pyroclastic material and water that flows down from a volcano, typically along a river valley.
The Earth's axis completes one full cycle of precession approximately every
26,000 years
When waves reach shallow water, the wavelength _______, and the wave height ______.
decreases, increases
On irregular shore lines, the energy of a wave is
concentrated mostly on the headlands by wave refraction.
Longshore drift moves water and sediment
along the beach in a zigzag path.
Longshore drift is due to
waves striking the shore obliquely.
Which of the following is the most likely trend in the evolution of coastal features?
sea cave,
sea arch,
sea stack,
sea cliff
Continued growth of a sandy beach can produce...
a spit.
a tombolo.
a baymouth bar.
In general, we can expect that on an irregular coastline
headlands will be eroded and bays will be the sites of deposition.
An atoll normally evolves from
a fringe or barrier reef.
Define Atoll
an island of coral that encircles a lagoon partially or completely.
There are two tidal bulges. One is caused by______and the other is caused by______.
gravitational attraction of the Moon, and centrifugal force.
Tsunamis are important because of their potential to destroy urban areas along shorelines. Which of the following statements is NOT accurate regarding tsunamis?
Tsunamis are triggered by tides, explaining why they are commonly called tidal waves.
What does NOT apply to low-latitude deserts?
The main effect of the wind is erosion of solid rock.
In general, the dominant EROSIONAL landforms in desert regions are developed by
running water.
A lag deposit, or desert pavement, is a concentration of
gravel-size particles left behind as wind selectively moves sand and dust from the surface.
Define Yardang
a wind-abraded ridge found in a desert environment.
Define Seif
a hill of sand built by aeolian processes.
Define Ventifact
rocks that have been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals. Found in arid environments.
A cobble that has been polished and abraded by wind action is called a
Ventifact
Wind transports material by
suspension.
saltation.
rolling and sliding.
What causes the migration of sand dunes?
Erosion of sand on the windward side and deposition on the slip face.
The steepest slope of a sand dune faces southwest, if the wind blows steadily from the
northeast.
Desertification can be caused by
climate change which brings drier conditions.
land use changes, including deforestation and overgrazing by cattle or sheep.
migration of sand dunes into the margins of a desert.
A limited supply of sand in a region of strong winds blowing in one general direction would likely produce
Linear dunes
The type of dune formed by winds blowing from at least three directions is a
Star
Why is Earth special?
It has an atmosphere
Its distance from the sun
Water can be in all three sta
Earth's Atmospheric Composition
78% Nitrogen 12% Oxygen
Define the Atmosphere
The sum of all the gasses surrounding Earth
What is the Atmosphere driven by?
Solar Energy
Define Hydrosphere
The total amount of water on the Earth's surface
What percentage of the Earth is covered with water?
71%
How much water is contained in the oceans?
98%
Define Biosphere
The sum of life on Earth. 1/2 of the Biosphere consists of insects.
What are shields, stable platforms, and mobile mountain belts?
Three major structural components of continents
Define Shield
A vast flat area of the continent with ancient rocks exposed.
Define Stable Platform
A Shield covered in sedimentary rock.
What is the combination of Stable Platform and Shield?
A Craton
Define Mobile Mountain
Deep deformations in the Earth due to the collision of tectonic plates.
Describe the Oceanic Ridge
It is the typical surface of solid Earth
Describe the Abyssal Floor
The ocean's floor divided into basins and hills
Describe Trenches
The lowest areas on Earth's surface. Usually next to volcanic chains
Define Seamounts
The top of an underwater volcano
Continental Margin
Where continents and ocean floors meet
Earth's Compositional layers
Core, Mantle, Crust
Earth's Physical Layers
Inner core (solid), Outer core (liquid), Mesosphere (solid), Asthenosphere (plastic), and the Lithosphere (solid).
Where does the energy for the Tectonic system come from?
Earth's internal heat and radioactive decay
What is the Eolian and what is it driven by?
A subsystem of the Hydrologic system. It involves the wind and its pattern. Its driven by solar energy.
Isostasy
When denser parts of the mantle push up through the buoyant crust and allow for mountains
What determines an atom's chemical properties?
The number of electrons
Isotope
Same atomic number with different numbers of neutrons
Ion
A particle that is electrically charged either positively or negatively
Define Mineral
Solid, homogenous, inorganic substance
Crystal Structure
The geometric structure of the atoms. The chemical composition
Cleavage
The tendency to split along weak points along a rock.
Hardness
can scratch it, or what it can scratch. Ranges from 1-10. 10 being the hardest (Diamond). A 1 being Talc.
The most common elements in Earth’s crust
Oxygen
The most abundant group of minerals in Earth's crust
Feldspar
What does Quartz look like?
Large clear crystals
What does Feldspar look like?
A pinkish dull colored stone
What does Mica look like?
Perfect cleavage. Sheety silicate mineral.
What do Mafic Minerals look like?
Dark and dense.
What do Clays look like?
Ultra fine grained with sheety silicates
Define Calcite
The most stable carbonate mineral. Tends to be in translucent blocks
Define Dolomite
A sedimentary carbonate rock found in crystals. Large crystals.
Define Gypsum
a very soft mineral composed of calcium sulfate dehydrate. Tends to be clear to white color.
Define Halite
NaCl. Salt. Clear to white. Isometric.
Examples of Foliated Rocks
Gneiss, schist, slate - direction of pressure is perpendicular.
Examples of non-foliated
Marble, greenstone, quartzite. Formed from equal pressure.
What type rock becomes sedimentary?
Any type of rock
What are the two classifications of Sedimentary Rock
Clastic (debris, mudstone, sanstone, shale) and chemical (limestone)
Law of Inclusion
chunk of a rock is older than the rock it is contained in.
Two types of clastics
angular clastic: Didn't move far from source
smooth clastic: traveled far
Name the 3 Tectonic Realms
Continent and Continent
Continent and Ocean
Ocean and Ocean
Name the 3 Tectonic Boundaries
1.Divergent: Plates move apart
2.Transform: Plates move horizontally past eachother (Strike-slip)
3. Convergent: Move towards eachother
What adds viscosity to magma?
Silica content and water
2 Main types of Bonding
Ionic: Opposite Charges
Covalent: Shared electrons
What are the requirements of a mineral
Inorganic, solid, formed by inorganic process
Ingeous rocks tell us what?
About the environment during their time period
Extrusive Igneous Rocks
Formed from lava: Rapid cooling
Intrusive Igneous Rocks
Formed from magma: slow cooling
How to classify Igneous Rocks
1. Texture: Aphanitic (crystals not visible and Phanitic (visible)
2. Composition: Felsic, Mafic, Ultramafic
Of the provinces of the ocean floor, which is the most active?
Trenches or Abyssal Plains
Non-foliated metamorphic rock protoliths
Limestone, dolomite (marble)
Sandstone (quartzite)
The most universal feature of Sedimentary rocks is?
Stratification (layering of rocks)
Porphoritic
Well formed crystals
Bedding Planes
Between layers of rocks
Fluvial Continent Environment
Braided: gravel and sand (low grade)
Meandering: Mud deposit (high grade)
Delta Transitional Environment
1. Stream, Tidal Dominated
2. Wave - Triangular
3. Tidal - oceans enter streams
Examples of Foliated Rock
Slate, schist, gneiss, mylonite
Examples of Non-foliated Rock
Marble, quartzite, greenstone
Uniformitarianism
Same laws of physics which applied millions of years ago still apply today
3 Types of Faults
Normal
Reverse
Slip-strike
Who was the first to attempt to discover the age of the Earth?
Archbishop Ussher
Father of Geology
James Hutton
Order of Earth's Time periods (oldest to youngest)
Pre-cambrian
Paleozoic
Mesozoic
Cenozoic
Describe the Pre-cambrian Period
Not a true era. 88% of Earth's history
Who discovered the actual age of the Earth and how?
Clair Patterson using radioactive decay.
How old is the Earth?
4.55 billion years old
What is the most common element in the Earth's crust and how much is it?
Oxygen 47%
Plutonic Rocks
Big molten masses which cool deep below the surface
Contact Metamorphism
Changes the elements of the rock
Regional Metamorphism
Change occurs deep in the crust usually in places where mountains form.
An intrusive and extrusive example of Mafic Rock
Gabbro (Intrusive)
Basalt (Extrusive)
An intrusive and extrusive example of Ultramafic Rock
Peridotite (Intrusive)
Komatite (Extrusive)
An intrusive and extrusive example of Felsic Rock
Granite (Intrusive)
Rhyolite (Extrusive)
To accomodate the new oceanic lithosphere created at midocean ridges, Earth's diameter and surface area are slowly increasing. (True or False?)
False
Volcanic activity is strongly associated with transform plate boundaries. (True or False?)
False
The youngest rocks of the basaltic crust on the sea floor are found along the oceanic ridge system. (True or False?)
True
The plate tectonics theory resulted largely from new data obtained from the ocean floor. (True or False?)
True
Convergent and divergent plate boundaries are marked by narrow zones of earthquakes and volcanoes. (True or False?)
True
Most continental crust is originally formed at divergent plate boundaries and then thrust onto the continents during plate collisions. (True or False?)
False
Plates move so slowly (less than 1 mm per year) that we cannot yet measure their movement but must rely solely on the geologic record. (True or False?)
False
Ridge-push is the force exerted on a tectonic plate by the forceful injection of magma into the midocean ridge. (True or False?)
False
Paleozoic glacial deposits found near the equator in India are evidence that the Earth's spin axis has slowly migrated to its present position in Antarctica. (True or False?)
False
The Pacific Plate is the largest tectonic plate and consists almost entirely of oceanic lithosphere. (True or False?)
True
What is not available to support the theory of continental drift but was later used to support the theory of plate tectonics?
Paleomagnetism
Paleoclimatic evidence of continental drift includes deposits of
glacial deposits, desert sandstone, gypsum.
What iare some accurate statements about how Paleozoic glacial evidence from the southern continents and India supports continental drift?
Without continental drift, the Paleozoic glacial deposits would indicate glaciers existed throughout the southern hemisphere, up to the equator, and in India.
During the same part of the Paleozoic, sedimentary deposits would indicate that most of the northern hemisphere was unglaciated, assuming the continents were where they are today.
Glacial striations indicate that, if the continents were not together, the glaciers would have had to move from the oceans and onto the continents.
Which of the following statements concerning patterns of magnetic reversal on the seafloor is NOT accurate?
The magnetic stripes cut across the oceanic ridges
Earth's magnetic field
Causes magnetic orientation to be recorded in cooling basaltic lavas
Sediment on the ocean floor
Is thickest toward the subduction zone and thin or absent on the ridges.
The Andes Mountains of South America are believed to be the result
of
The convergence of lithospheric plates
What is not a major process at convergent plate margins?
Extrusion of large volumes of basaltic magma
What is NOT a major process at divergent plate boundaries?
Eruption of andesitic lava
Which of the following does not indicate the direction of plate movement?
The trends of folds in sediments found at the ridge
Deep-focus earthquakes occur almost exclusively at convergent plate boundaries.
True because "cold" brittle rocks are thrust to great depths
If the interior of a planet is homogeneous, the paths followed by seismic rays will curve at depth
False
A liquid core is indicated by the fact that P waves do not travel through liquid and do not travel through the core
False
Compared to their velocities in the lithosphere, seismic wave velocities are not affected by the asthenosphere and continue to increase with depth.
No. The upper part of the asthenosphere is marked by a decrease in seismic velocity.
Seismic tomography shows that the continents are underlain by thick cool roots as compared to the ocean basins.
True
Compared to bedrock, unconsolidated sediments or landfills are good foundation materials because they lessen the amplitude of earthquake shaking.
False
The velocities of P and S waves decrease abruptly as the waves are transmitted across the boundary between the crust and the mantle
False. It's when they reach the mantle
If P and S waves both arrive at nearly the same moment at a seismograph station, the station is very close to the epicenter of the earthquake.
True. Each of these seismic waves moves at a different speed.The greater the distance to the epicenter, the more delay there is between the arrivals.
Earthquakes are thought to be caused by the sudden release of energy stored in rocks that have been strained (deformed) beyond their elastic limit by fault movement
True. This is the elastic rebound theory
S waves (shear or secondary waves) can be transmitted through solids, liquids, and gases.
False
P wave velocity increases with depth in the mantle because
The pressure causes the mantle rocks to become more rigid.
Certain depths metamorphose less dense minerals into more dense minerals.
Which of the following causes most of the Earth's major earthquakes?
faulting of rock sequences
Earthquakes are caused by
ruptures that occur where rocks are strained beyond their elastic limit
What is the point on the Earth's surface directly above the place of origin of an earthquake called?
The epicenter
In P (primary) waves, the particles in a rock body move
Back and forth parallel to the direction in which the wave travels.
Which seismic wave type cannot move through a liquid?
S waves
The distribution of earthquakes on Earth
delineates plate boundaries.
Which of the following statements is true of earthquakes?
Oceanic ridges and transform faults are characterized by shallow earthquakes.
Earthquakes at converging plate margins occur in a zone inclined downward beneath the adjacent continent or island arc.
Earthquakes along transform faults originate from lateral movement.
The most intense and widespread zone of seismic activity occurs
Along convergent plate boundaries
The size of Earth's core is indicated by the shadow zone for
Both P and S waves
The oceanic ridges are the sites of the most active volcanism on Earth
True
Fast spreading ridges have long narrow rift zones and steep sides, as compared to slow spreading ridges.
False
The depth to the ocean floor depends on the seafloor's age.
True. As it ages, the seafloor cools and sinks.
Earthquakes along divergent plate boundaries are almost always less than about 10 km deep.
True. The lithosphere is relatively thin and is not thrust to great depths as it is at convergent boundaries.
Measurements show that heat flow is 10 times less along the ridge crests than for average oceanic crust.
False. The ridge crest has much higher heat flow than average oceanic crust.
Gravity measurements across an oceanic ridge show high values at the crest and lower values on the adjacent flanks.
False. The opposite is true, because hot low density materials underlie the ridge.
In ophiolites, the sheeted dikes grade downward into a zone of massive gabbro
True
Metamorphosed basalt may be the most abundant kind of metamorphic rock exposed near Earth's surface
True. The seafloor is composed of basalt, much of it metamorphosed.
All oceanic rocks appear to be more than 200 million years old, whereas the great bulk of continental crust is less than 700 million years old.
False. There are no oceanic rocks over 200 million years old, because it has been subducted.
Continental rifts are typified by reverse faults, deep earthquakes, and andesitic magmatism.
False. This is characteristic of subduction zones, not rifts.
As the new oceanic lithosphere moves away from the crest of the ridge it
cools, becomes more dense, and subsides.
Only shallow earthquakes occur at midocean ridges because
the lithosphere is thin and earthquakes cannot occur in the ductile asthenosphere.
The proper sequence of rock, from bottom to top, in a typical ophiolite is:
gabbro, sheeted dikes, pillow basalts, sediment.
On continents, sedimentary rocks accumulate in vertical stacks with essentially horizontal “time lines” between them. What is the orientation of time lines in oceanic crust?
by decompression melting in the upper mantle. It does not come from deep in the mantle.
What causes seafloor metamorphism?
extreme heat along the oceanic ridge and hydrothermal alteration from hot fluids
During rifting, continental crust becomes
thinner because of stretching and extension of the crust.
Which of the following would rarely be associated with continental rifts?
Tight folds and thrusts. These are common in extensional areas.
Which of the following represents an intermediate stage of continental rifting?
The Red Sea
If on a graph, the Y-axis is Sea Depth, and it is a negative slope (top left to bottom right) what is the X-axis?
age in millions of years
Which methods are useful when studying the ocean crust?
seismic studies
satellite observations
magnetic studies
direct observation
A transform fault usually consists of a single simple fault plane.
False. A transform fault zone is essentially a braided network of strike-slip faults.
Continental transform faults extend to much greater depths than oceanic transform faults.
True. This statement is true because continental lithosphere is thicker than oceanic.
Strike-slip faults are the most important type of fault found at transform plate boundaries.
True. A transform boundary essentially is a large strike-slip fault.
In contrast to earthquakes at convergent plate margins, all earthquakes at transform plate boundaries are shallow.
True
The plate tectonic theory predicts that California will eventually sink into the ocean.
False. Western California is predicted to move northward along the San Andreas transform with the Pacific Plate
Metamorphism at transform plate boundaries is typified by high pressures and low temperatures that create blueschist facies rocks.
False. This is characteristic of convergent margins, where subduction carries rocks to great depth.
There is not much deformation at transform faults with small offsets (and fast shearing rates) because the temperature difference across the fault is small.
False. The crust is hot, weak, and easily deformed.
The volcanoes of Hawaii lie on a leaky transform zone related to the East Pacific rise.
False. Volcanoes as active as those in Hawaii are very rare along transform faults anywhere in the world.
The total offset along some continental transform faults, like New Zealand's Alpine Fault, is measured in hundreds of kilometers.
True
The Dead Sea transform system is a good example of a ridge-ridge transform.
False. This transform connects the Red Sea ridge to a convergent plate margin.
Although transform plate boundaries connect convergent and divergent boundaries, crust is NOT ______ at this type of boundary.
created or consumed
Transform plate boundaries are dominantly
Zones of shearing
Shearing along faults at transform plate boundaries produces tectonic breccia and
mylonite.
On the ocean floor, one side of a fracture zone will be higher than the other because
one side is hotter than the lithosphere on the other side. Earthquakes occur all along transform faults but not on just one side.
Compression can occur along a continental transform fault where
The trace of the transform fault is not straight. Shallow earthquakes are common along the entire length of a transform fault.
Magmatic activity along transforms characteristically produces
small, local extrusion of basalt or no volcanism at all. Granite is rarely produced along transform faults.
What happens during transtension along a transform fault?
Sedimentary deposits accumulate in a subsiding basin.Transtension areas are areas of extension, and pull-apart basins are common.
What happens along a transform boundary where cold oceanic crust is juxtaposed against a spreading midocean ridge?
Volcanism declines and development of normal oceanic crust at the ridge is restricted.
Which of the following is NOT a feature of a transform with a large ridge offset and a slow spreading rate?
a small temperature difference between the two plates on either side of the transform
Along some midocean ridges, earthquakes are more common along the transform fault offsets than along the actual midocean ridge because
deformation is taken up by ductile flow under the hotter ridge.
On a shaded relief map, two parallel lines signify
A fracture zone and transforming plate boundary
During the convergence of two continental plates, one plate must always subduct deep into the mantle.
False. Continental crust is too buoyant to subduct.
Some deep earthquakes at subduction zones may be caused by abrupt metamorphic mineral changes in the subducting slab.
True. This statement accurately describes what is thought to happen in a subducting slab.
Extensional deformation is rare at convergent plate boundaries, such as the one near Greece and Turkey.
False. Mild extension is the dominant type of deformation at most oceanic island arcs. It also occurs at some continental arcs.
Many volcanoes at convergent plate margins are explosive shield volcanoes that erupt basalt.
False. Most are explosive composite volcanoes that erupt basalt, andesite, and rhyolite.
Magma formed in a subduction zone is formed by decompression melting
False. Dehydration of the slab induces subduction zone magmatism.
Blueschist facies rocks are created under low temperature, high pressure conditions.
True
The volume of continental crust appears to have remained constant throughout most of geologic time.
False. Continental crust appears to have grown with time.
Only shallow earthquakes occur along subduction zones because the temperatures in the mantle are simply too high.
False. In fact, it is because the subducted plate is relatively cold that deep earthquakes do occur in this setting.
Much of western North America consists of accreted terranes that are Mesozoic or Cenozoic in age.
True
Subduction occurs because oceanic plates cool and become denser than the underlying mant
True. This process is fundamental to the operation of the plate tectonic system.
Which of the following areas is experiencing the convergence of two continents?
The Himalayan region of southern Asia. This is an example of continent-ocean plate convergence.
Which of the following is NOT a major process at convergent plate margins?
Extrusion of flood basalts
An oceanic plate is relatively buoyant if
It contains seamounts and plateaus of basaltic lava. The plate is hot and young.
The convergence of two oceanic plates typically produces
A volcanic island arc. Deformed sediments in an accretionary wedge.
At subduction zones, earthquakes occur in ______, whereas during continent-continent collision, earthquakes occur in ______
a narrow inclined zone extending to great depths, a broad shallow belt. Think about the geometry of the earthquake belts at these margins.
The Sea of Japan was probably caused
when backarc spreading rifted the volcanic arc away from the Asian mainland. Mantle plumes are not responsible for creating the Japanese island arc.
Which of the following does NOT control whether a certain convergent margin experiences compression or extension?
the direction (north, south, east, or west) of plate subduction. Convection in the asthenosphere is a determining factor in crustal deformation.
The accretionary wedge, found at ocean-ocean and ocean-continent convergence plate zones, is all of the following EXCEPT
a structurally simple mixture of rock types known as melange.
The development of island arcs is significant for the growth of continents because
Andesite is produced at island arcs. Island arcs may be accreted to a continent. The igneous rocks formed there are too buoyant to be subducted.
In the forearc of a subduction zone, ______ metamorphism is characteristic, while in the magmatic arc, ______ metamorphism is common.
high pressure/low temperature, low pressure/high temperature
Basalt is the most common type of lava found at ocean islands related to mantle plumes and at midocean ridges.
True. Basalt is the most common type of lava erupted at both of these settings, but the basalts have different trace element characteristics that show they have quite different origins.
Measurements of heat flow in Yellowstone National Park are abnormally high, almost 30 times the continental average, because of the presence of many hot springs and geysers.
False. The presence of hot springs and geysers is a result of the high heat flow, not a cause of it.
Mantle plumes are thought to rise from the core-mantle boundary because they are hotter and less dense than the surrounding mantle.
True. This is the mechanism that probably explains the rise of mantle plumes.
Geochemical studies show that the basalt erupted from hotspot volcanoes is different from the basalt that erupts at midocean ridges
True. Although basalt is common in both settings, they are distinctly different from one another.
The volume of igneous rock produced in mantle plumes far exceeds that produced at divergent plate boundaries.
False. Even though some hotspot volcanoes like Hawaii are very active, they do not produce nearly as much as all of the submarine volcanoes that dot the oceanic ridges.
Starting plumes are associated with the eruptions of flood basalt and may have formed the large oceanic plateaus.
True. Flood basalt provinces and starting plumes do seem to be genetically related.
The largest volcanic edifices on Earth are the volcanic islands and seamounts that develop above mantle plumes.
True. Mauna Loa is actually the highest volcano on the planet if you measure it from the sea floor where it originates.
Mantle plumes appear to move at about the same rate as the plates, but in opposite directions.
False
Because hotspots are fueled by rising material from the mantle, eruptions of rhyolite are rare, even on the continents.
False
Mantle plumes are so narrow and indistinct that they have not yet been detected by seismic experiments.
False
Which of the following statements is NOT true with regard to the boundary layer surrounding Earth's core?
The boundary layer is much more viscous than the mantle above it.
Eruptions from volcanoes related to mantle plume are
Quiet and involve basaltic lavas.Explosive and involve silica-rich lavas and ash flows. Depending on location
When the head of a new (starting) plume reaches the lithosphere, which of the following occurs?
crustal uplift. Eruptions from starting plumes are usually rapid and episodic.
Which of the following is true about intraplate volcanic activity?
It probably represents local mantle plumes. Intraplate volcanic activity, such as at Yellowstone, is probably related to mantle plumes.
Basaltic magma from mantle plumes is formed because of
decompression melting as the plume rises. The melting point of peridotite, a common rock in the mantle, decreases slightly as the pressure decreases.
The large bulbous head of a rising mantle plume
enlarges as it rises partly because cooler mantle material is pulled into the plume.The surrounding mantle opposes the rise of the plume.
The modern development of the island of Hawaii is a good example of the effects of
A rising plume tail. The tail is thought to be responsible for the development of hot spots
The earthquakes related to the Yellowstone hotspot are
caused by the movement of magma and deformation related to the crustal bulge near Yellowstone. The Columbia River Plateau is relatively seismically dormant.
With regard to mantle plumes and hotspots, which of the following is true?
Flood basalt provinces are important clues in interpreting the history of many divergent plate boundaries.The Siberian flood basalt province is one of the most voluminous but did not cause continental rifting.
Extensive mantle plume eruptions can make Earth's climate warmer by releasing which volcanic gas?
CO2
The important minerals on which modern civilization depends constitute a relatively large part of Earth's crust.
False
Important ore deposits are not formed by metamorphism.
False. Many important minerals are found only in very low concentrations.
Solar energy is the most important renewable, or sustained-yield, energy source.
True
One problem with geothermal energy is that most of Earth's heat is far too deep to tap artificially.
True. The depth of high temperatures is a major problem.
It is estimated that the oil supply will decline to near exhaustion by the year 2070.
True. Oil is a nonrenewable resource.
According to recent studies, the major factor in limiting population and industrial growth will be consumption of resources by an increased population.
True
Almost all important mineral deposits are related to contact metamorphism and hydrothermal alteration around igneous intrusions.
False. Many important ore deposits form by igneous and sedimentary processes, as well as by regional metamorphism.
Deep weathering of igneous rocks in tropical climates may produce bauxite, our most important source of aluminum.
True
Although oil in the United States will probably be consumed in less than 100 years, coalfields can probably sustain that country's rate of energy consumption for several hundred years.
True.Coal is more abundant than the remaining oil reserve in the United States.
Earth's major oil and gas fields are found on the continental shields where organic materials in these ancient rocks has had enough time to change to petroleum & natural gas.
False. Oil and gas are typically formed from organic material trapped in much younger sedimentary rocks.
Most of our iron ore comes from
Banded iron formations originally deposited as sediments.Banded iron formations are the most important source of iron listed.
Hydrothermal fluids that carry dissolved metals may form
Hydrothermal fluids form in many different environments where there is hot water.
Convergent plate margins are associated with important deposits of all of the following EXCEPT
Thick deposits of evaporites formed in closed basins.These are common at convergent margins.
Copper, lead, zinc, gold, and silver are commonly concentrated by
hydrothermal solutions associated with cooling magma.
Which of the following is the best example of a mineral concentrated by magmatic segregation?
chromite
Commercial deposits of evaporite minerals may consist of
A and B
Porphyry copper deposits are associated with
Convergent plate boundaries. Magmas are rare at transform boundarires.
An example of harnessing geothermal energy is
Using geothermally heated groundwater.This is not how geothermal energy is harnessed.
The most common source of energy currently in use is
fossil fuels
The conditions necessary for the accumulation of oil in an economically useful deposit include all of the following EXCEPT
High-grade metamorphism.This is a necessary condition.
In contrast to the larger solid planets, most small planets and moons have ancient surfaces.
True.No. Size is an important attribute for determining the cooling rate of a planet.
Almost no global tectonic activity has occurred on the Moon during the last 3 billion years.
True.Yes. With the exception of impact processes, the Moon appears to have been quite inactive for a long time.
The major channels on Mars are believed to have been produced by running water draining from the southern highlands and emptying into the low northern plains.
True. This is the current theory to explain the major channels on Mars.
Neptune's largest satellite, Triton, has a surprisingly large variety of geologic features including ice caps, fractured terrains, lava lakes, and active volcanic eruptions.
True. These features are found on Triton.
In contrast to Earth, the atmospheres of Venus and Mars are both rich in carbon dioxide.
True. This is a correct statement because most of the carbon dioxide once in Earth's atmosphere has been removed to make carbonate sedimentary rocks.
Europa, a moon of Jupiter, may have a deep ocean of liquid water beneath a relatively thin shell of ice.
True. Europa may be the only body other than Earth to have abundant liquid water near its surface today.
All meteorites that fall to Earth probably come from small, rocky asteroids, rather than larger objects like Mars or the Moon.
False. Although most meteorites appear to come from asteroids, a few dozen have been found that look like they come from Mars and from the Moon.
Chicxulub impact crater is the buried product of a collision of a large comet or asteroid into Mexico's Yucatan peninsula. It is hypothesized to be responsible for the extinctions at the end of the Mesozoic Era (end of the Cretaceous Period)
True. This large crater is buried beneath layers of sedimentary rock and has the exact age of the mass extinctions at the end of the Cretaceous Period.
The Moon has much less water than Earth. The most recent theory to explain this difference holds that the Moon formed in another part of the Solar System and was then captured by Earth's gravity.
False. To capture the Moon and place it in its orbit would be very difficult.
With a few notable exceptions, most of the moons of the outer planets are cold, icy bodies with ancient cratered surfaces.
True. The photographs taken by the Voyager and Galileo spacecrafts show that this is true.
Which of the following is NOT an important characteristic of comets?
They are made mostly of dense silicates so common in the outer solar system.
Of the following, which was most important in establishing the sequence of events in lunar history?
the principle of superposition. There are no fossils on the Moon.
The inner planets are small and dense compared to the outer planets. They probably
formed from rocks and metals that crystallized from the solar nebula at relatively high temperatures. The outer planets contain ices that formed under these conditions.
Which of the following is NOT a common feature on Mars?
Rayed craters. Mars has large dune fields.
Which of the following features have been found on Venus?
lava flows, dunes, folds and thrust sheets
The features on Mercury suggest that its geologic history is
Similar to that of the Moon
The dominant geologic process in the early history of all planetary bodies in the solar system appears to have been
intense meteorite bombardment.This process is not revealed by the bodies with the oldest surfaces.
Which of the following planetary bodies is believed to be the most volcanically active body in the solar system today?
Io
Saturn's largest moon, Titan, is similar to Earth in that it
has an atmosphere that is mostly made of nitrogen.