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183 Cards in this Set

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⦁ Rank the three different plate boundary types in terms of the severity of the earthquakes they produce.

Convergent, Transform, and Divergent

⦁ Convergent Boundary:

Most earthquakes occur along this kind of boundary,




most earthquakes in mountains are associated with this kind of boundary,




most earthquakes near coastlines occur along this kind of boundary.

Divergent Boundary:

Most earthquakes in the middle of the oceans occur along this kind of boundary.

⦁ What are the four primary zones in Earth’s interior?

Crust, mantle, outer core, inner core.

⦁ What data provided information about the existence of different zones within Earth?

P-wave and S-wave arrival times.

⦁ Which of the following statements about seismic wave ray paths is most accurate?

Seismic waves move along curved ray paths because of changing properties of rocks.

⦁ Why do we believe Earth’s outer core is a liquid?

S waves do not travel through the outer core, and p waves slow down and refract at the boundary between the mantle and the outer core.

⦁ Why do geologists believe the inner core is solid?

P waves refract at the boundary between the outer core and inner core.

⦁ How could you test whether the core of another planet were completely solid?

? Set off a bomb to create seismic waves. If S waves arrive on the opposite side of the planet, then the core is solid.

⦁ What was the response by the scientific community when Alfred Wegener published The Origin of Continents in 1915?

His ideas were generally viewed with disbelief, rejected, and considered improbable or impossible.

⦁ Wegener’s early proposal of continental drift was not taken seriously because of his_____

failure to provide a plausible cause

⦁ (1) The slowly increasing distance between South America and Africa is due to_____

seafloor spreading

Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from a______

hot spot

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

sedimentary rock

Australia is composed of relatively old and thick _________

continental crust.

The extremely deep ocean Marianas Trench is a result of ______

subduction.

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

Seafloor crust

The earthquakes that occur in Southern California generally occur above a_________

fault.

⦁ How do plates move at divergent plate boundaries?

Plates move apart.

⦁ How do plates move at convergent plate boundaries?

Plates move together.

⦁ How do plates move at transform plate boundaries?

Plates move side by side.

⦁ In general, where do both earthquakes and volcanic eruptions occur

At divergent and convergent plate boundaries.

⦁ What forms at divergent plate boundaries?

New oceanic lithosphere

⦁ In general, where do volcanoes form in subduction zones?

On the overriding plate, away from the convergent boundary.

⦁ Why are volcanoes not found at transform boundaries?

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

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

An ocean.

⦁ What is convection?

A cycle of moving material formed by the rise of less-dense material and the sinking of denser material.

⦁ What accounts for most tectonic plate motion?

Forces at subduction zones

⦁ What is the relationship between temperature and density?

In general, warmer materials are less dense, and colder materials are dense.

⦁ Which of the following terms best characterizes upwelling in the asthenosphere

Diffuse.

⦁ What is a plume?

A zone of upwelling material originating at the outer core-mantle boundary.

⦁ What features at the surface provide evidence of plumes?

Hot spots.

⦁ Where are tectonic plates located?

At Earth’s surface.

⦁ What are the three types of plate boundaries?

Divergent, convergent, and transform.

⦁ 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 that correlates closely with plate boundaries.

⦁ Which plate boundary is NOT associated with volcanic eruptions?

Transform

⦁ Which phenomenon can explain the presence of volcanoes in the middle of the Pacific Ocean?

Hot spots

⦁ Which type of plate boundary is most closely associated with uplifting continental regions and mountain building?

Convergent boundaries

⦁ Which evidence supports the theory of plate tectonics?

The Glomar Challenger found younger rocks and less sediment cover when approaching oceanic ridges.

⦁ The current interest in continental drift was started with the notion of sea-floor spreading, which was propounded by Hess and Dietz in the

1960s.

⦁ If you travel away from a mid-ocean ridge you will find

increasingly older rocks.

⦁ Research since the 1970s has identified the cause of plate tectonics to be

convection.

Would be found at a divergent boundary

Normal faults, volcanoes producing mafic lavas.

Would not be found at a divergent boundary

Thrust faults, volcanoes producing andesitic lavas.

⦁ Plate boundary convergence and the process of ___________ are responsible for the formation of the Andes Mountains – a linear mountain range that parallels the western coast of South America.

subduction

⦁ New crust is created at a _____ plate boundary.

divergent

⦁ New oceanic crust formed at spreading centers creates topographic features on the ocean floor called ________.

mid-ocean ridge

⦁ At a ________ plate boundary associated with a physical feature called an _______, old basaltic oceanic crust is recycled back into the middle.

convergent, oceanic trench

Divergence is to moving away as convergence is to ____________.

moving toward.

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

divergent, convergent, transform.

Which geologic features are associated with divergent boundaries?

Mid-ocean ridges and continental rift valleys.

Which geologic features are associated with convergent boundaries?

Ocean trenches and volcanoes.

Where is the youngest ocean floor found?

Along the crest of mid-ocean ridges.

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.

What is a volcanic arc?

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

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

Andes and Cascades

⦁ Which feature is found at a divergent boundary?

A rift valley.

⦁ Which location is the result of oceanic-continental convergence?

The Cascades and Mt. St. Helens

⦁ What differentiates oceanic-oceanic convergent plate boundaries from oceanic-continental convergent boundaries?

Volcanic island arcs

⦁ Where is one plate being subducted under another plate?

Along the Aleutian Trench

⦁ The Himalayas were formed by crumpling of plate edges in a ________ zone.

convergent

⦁ Which of the following is most closely associated with a mantle plume?

The Hawaiian Islands

⦁ What is the term for a piece of crust which has been in a collision along a convergent crustal boundary and become accreted to another crustal plate?

Terrane

⦁ Based on the evidence in the Eruption of Shiveluch Volcano folder, which of the following terms associated with volcanism best describes the grey plume emanating from the volcano?

Pyroclastic material

⦁ What geologic process is related to caldera formation?

Volcanism

⦁ How do calderas form?

Calderas form when the summit of a volcano collapses.

⦁ Where is Crater Lake?

Oregon

⦁ In addition to rock deposits, what evidence do we have that the eruption that preceded the formation of Crater Lake was very large?

The eruption was so large that the magma chamber under Crater Lake partially emptied, causing the volcano to become unstable and collapse.

⦁ Why does Crater Lake have an island in it?

The volcano is still active, and a new volcanic peak has formed.

⦁ Which of the following are types of volcanoes?

Composite volcano, shield volcano, cinder cone.

⦁ What information do geologists use to classify volcanoes?

Shape and type of deposits.

⦁ Cinder cones are made of

pyroclastic deposits

⦁ In general, how often do most cinder cones erupt?

Most cinder cones erupt once.

⦁ What are shield volcanoes generally made of?

Basaltic flows.

⦁ What is the range of shield volcano height?

300 to 10,000 meters

⦁ What are composite volcanoes made of?

Pyroclastic deposits and basalt flows.

⦁ Why are shield volcanoes wider than composite volcanoes?

The lava that flows out of shield volcanoes is more fluid than the lava that flows out of composite volcanoes.

⦁ What type of magma erupts out of dome complexes?

Felsic magma.

⦁ What type of volcanoes are the tallest?

Shield volcanoes.

⦁ What is the range of the dome complex height?

500 to 2,000 meters.

⦁ What type of volcano is Mount Fuji, the classic icon of Japan?

Composite cone.

⦁ Which of the following is NOT an intrusive volcanic landform?

Caldera.

⦁ Flood basalts cover much of the ocean floor, India, and in North America, the

Columbia Plateau.

⦁ Mount St. Helens is

likely to vigorously erupt again.

⦁ The nature of a volcanic eruption is determined largely by the ________ of the magma.

Chemistry

⦁ Which of the following are waves generated by earthquakes?

Tsunamis

⦁ Lava flows often create

flat plains.

⦁ The ____________ is an area of extensive flood basalts.

Columbia Plateau

⦁ What type of volcano is Mount Saint Helens?

Composite

⦁ Which of these most directly triggered Mount Saint Helens main eruption?

A massive landslide.

⦁ There had been many earthquakes in the area prior to this eruption. Why did this last earthquake trigger a massive landslide?

Moving magma had over-steepened the mountain slopes.

⦁ If previous eruptions had left Mount Saint Helens with a different shape, what differences might have influenced the timing of the eruption?

If the northern slopes had been less steep initially (same height), the eruption would likely have happened later.




If the volcano had been significantly shorter initially (same steepness), the eruption would likely have happened sooner.

⦁ How much material was removed from the volcano? Mount Saint Helens

2.8 cubic kilometers of rock

⦁ What is a fault?

Fractures along which rocks move.

⦁ What are rocks below and above a fault called?

The footwall below and the hanging wall above.

⦁ Which type of force is responsible for normal fault formation?

Tensional force.

Which type of force is responsible for reverse fault formation?

Compressional force

Which type of force is responsible for normal strike-slip formation?

Shear force.

Which type of fault has no vertical motion of rocks associated with it?

Strike-slip fault.

⦁ A ___________ is the same thing as a pyroclastic flow.

nuee ardente

⦁ A volcanic mud flow is known as a ________

lahar.

⦁ What lies underneath volcanic features at Earth’s surface?

Magma chambers and volcanic conduits.

⦁ What is the difference between a dike and a sill?

A dike intrudes across sedimentary layers, and a sill intrudes between sedimentary layers.

⦁ What is a volcanic conduit called after the conduit has solidified and been exposed by erosion?

A volcanic neck.

⦁ Why are volcanic rocks often exposed at Earth’s surface as hills, ridges, and mountains surrounded by areas of lower elevation?

Volcanic rocks are often more resistant to erosion than surrounding rock.

⦁ What is a magma chamber called after it and the conduit have solidified and been exposed by erosion?

A batholith.

⦁ What is the igneous body shown in the cross-section?

A Dike

⦁ The most massive form of igneous intrusion is a

batholith.

⦁ Which type of force causes folding?

Compressional force.

⦁ What is an anticline?

A fold shaped like an upside-down U.

⦁ What is a syncline?

A fold shaped like a right-side-up U.

⦁ Imagine that an anticline has been eroded to a flat surface. How would the rock age change as you walked across that flat surface?

Rocks would be youngest on the edges and oldest in the middle.

⦁ Imagine that a syncline has been eroded to a flat surface. How would the rock age change as you walked across that flat surface?

Rocks would be oldest on the edges and youngest in the middle.

⦁ What produces plunging folds?

A combination of folding and tilting.

⦁ What does the term “plunging fold” mean?

A fold that is tilted down into the Earth

⦁ Imagine that a fold has been eroded to a flat surface. In general, how would you know if this fold is plunging?

Nonpunging folds look like straight lines at the surface, and plunging folds look like wavy lines.

⦁ In folded terrain, a simple symmetrical down fold is termed a

syncline.

⦁ A simple symmetrical upfold is called an

anticline.

⦁ A crustal block which is down thrown with a steep fault scarp on either side is a

graben.

⦁ Grabens are commonly found in association with

horsts.

⦁ Which of the following are fault-block mountains?

Sierra Nevada

⦁ Which situation would result with older sediments overlying younger sedimentary rocks?

Thrust faulting

⦁ Which of the following refers to the surface of the Earth directly above the center of an earthquake?

Epicenter

⦁ Which earthquake wave type travels most slowly?

S

⦁ In earthquakes, P waves

are faster than S waves.

⦁ Loose, water-saturated sediments may undergo ______ during an earthquake.

liquefaction

⦁ What are the types of mountain glaciers, and how are they related?

A cirque glacier can become a valley glacier and then a piedmont glacier.

⦁ Continental ice sheets smooth and round the terrain while mountain glaciations tend to

steepen slopes and increase local relief.

⦁ In glacially-influenced mountain valleys are_________ lakes which are series of shallow lakes which bear a fancied resemblance to beads on a rosary.

paternoster

⦁ During the Pleistocene, an ________ was a time of ice retreat.

interglacial

⦁ The Earth has been deglaciating for the last ______years.

9000

⦁ The time since 10,000 B.P. is most properly known as the _____ epoch.

Holocene

⦁ During the last Ice Age, sea level was

much lower than today’s sea level.

⦁ Where do glaciers form?

In places where more snow falls in the winter than melts away in the summer.

⦁ What is the snow line?

The elevation above which snow persists throughout the year.

⦁ What is the zone of wastage?

The part of a glacier where snow melting exceeds snow accumulation.

⦁ Under what condition will the front of a glacier remain stationary?

Glacial fronts remain stationary when melting and snow accumulation are equal.

⦁ What is an end moraine?

A ridge of debris deposited at the end of a glacier.

⦁ How does an end moraine form?

Pieces of rock are transported to the front of a glacier as ice within the glacier moves.

⦁ Will plucking occur if a glacier is not advancing?

Yes, because glacial ice is still moving inside the glacier even if the glacier’s front is not advancing.

⦁ Which demonstration illustrates best how a glacier moves?

Smash a ball of clay against a gravel driveway surface, and watch the clay spread.

⦁ What is the impact on a glacier in a year when melting exceeds snowfall?

The area of the glacier shrinks.

⦁ ________ is a granular snow which is beginning to coalesce into glacial ice.

Neve

⦁ The lowest part of a glacier where there is a net annual loss of ice from melting and sublimation is the zone of ________

ablation.

⦁ Snow is changed by __________ into glacial ice.

pressure and weathering

⦁ The movement of a glacier along its bottom, lubricated by meltwater, is known as

basal slip

⦁ The glacial scouring by bedrock embedded in ice is erosion by

abrasion.

⦁ Drift is

a term which is a misnomer out of biblical literature.

⦁ Unsorted debris from ice sheets, after deposition, is known as

Till

⦁ What is a mountain that has been eroded on all sides by at least three cirque glaciers?

Horn

⦁ What is the ocean-filled portion of a previously glaciated valley called?

Fjord

⦁ A deglaciated cirque often contains a basin in which a _____ can be found.

tarn

⦁ Glaciers carve ___–shaped valleys.

U

⦁ The maximum extent of a glacier is marked by a____________

terminal moraine.

⦁ The first comprehensive theory of continental drift was propounded by

Wegener

⦁ The primary reason that scientists initially rejected Wegener’s continental drift hypothesis was due to lack of ______________

mechanism.

⦁ Where in the world today is a divergent plate boundary presently creating a continental rift valley?

East Africa

⦁ Name a geographic location where an oceanic-oceanic convergent boundary type can be observed today:

Aleutian Islands

⦁ Name a geographic location where a continental-continental convergent boundary type can be observed today:

Himalayas

⦁ Name a geographic location where an oceanic-continental convergent boundary type can be observed today:

Cascades, Andes

⦁ What is the term for a piece of crust which has been in a collision along a convergent crustal boundary and become accreted to another crustal plate?

Terrane

⦁ Alaska and the Northwest

is the part of the United States where one could see terranes.

⦁ The Red Sea is an example of

a recent continental rupture.

⦁ Which of the following is most significantly associated with a mantle plume (hot spot)?

The Hawaiian Islands and Yellowstone Park

⦁ Massive structures have size and width to them

batholith, laccolith

Tabular structures are thin in one dimension

dike, sill

⦁ Concordant. Follows things.

Laccolith, sill

⦁ Discordant. Goes against things.

Batholith, dike

⦁ Rank the magma compositions from lowest viscosity to highest viscosity:

Mafic < Intermediate < Felsic

⦁ Rank the magma composition from most explosive volcanic eruptions to the least explosive eruptions.

. Felsic – Intermediate – Mafic

⦁ P-Waves: Primary, (Phast –fast);

S-Waves: Secondary, slow, solid.

⦁ The general term for material deposited by a glacier is

drift.

The term for material deposited directly by glacial ice is

till

All till is drift, but not all drift is till.

All till is drift, but not all drift is till.

⦁ Glaciers erode by two methods:

Plucking and abrasion

⦁ A reverse (or thrust) fault is a fault in which (a.)____________ and is the result of (b.)______

the hanging wall has moved up relative to the footwall




compressional forces.

⦁ The point in the subsurface at which slip is initiated along a fault plane (the actual point of energy release) is

the focus of the earthquake

⦁ If earthquake A has a Richter magnitude of 4 and earthquake B has a magnitude of 5,

approximately 32x more energy was released in B.

⦁ The granular, recrystallized snow that eventually is buried and fused into interlocking ice crystals that become true glacial ice is called

firn.

⦁ Where is the largest extent of ice sheets occurring today?

Antarctica

⦁ Of the following locations, which is not currently covered with an ice sheet?

North Pole and Northern Canada

⦁ Ice is truly glacial when

firn ice is buried and metamorphically recrystallized.

⦁ If ice ablation is greater than ice accumulation,

, the glacial ice will move down the valley and the glacier is said to be retreating.