GLY 101 Exam 3

Which physical property was responsible for determining how earth materials separate into interior layer at the time of earths formation

density

What is a mineral phase change

atoms in a mineral are rearranged into a denser and more stable structure

______ is the process when materials separate into different layers due to density

differentiation

What is the major difference between the inner core and the outer core

the inner core is solid while the outer core is liquid

What is the primary method scientists use to determine the layering of the interior of the earth

seismic waves

What will happen to a seismic wave when it is reflected

the wave will be bounced back toward the source

what will happen to a seismic wave when it is refracted

the wave will be bent when passing into a material of differing density

which seismic waves would be most useful in determining the extent and thickness of the earths interior layers

P and S waves

Which of the following materials will allow for the fastest transmission of seismic waves

rigid, less compressible material

what is diffraction

a seismic wave is bent when it passes by a curved surface

why do seismic waves follow strongly curved paths as they move through the interior

their velocities are changed because of increasing pressure with depth

a relatively weak layer in the earth due to temperature is known as the _______

asthenosphere

where is the thinnest continental crust in north America

basin and range region

where is oceanic crust generated

along divergent plate boundaries

the _____ is a seismic boundary between the crust and the mantle where there is a dramatic increase in seismic wave velocity

moho boundary

the ______ layer is thought to have large variations in composition as well as temperature

D"

Which layer or layers are believed to have convection cells

mantle and outer core

which layer is thought to be the birthplace of deep mantle plumes

D" layer

the inner core is believed to rotate independently from the outer layers of earth. why is this possible

the inner core is separated from the mantle by the liquid outer core and can spin freely

where is the highest rate of heat flow escaping the earths interior

at mid ocean ridges

______ is a technique to view three-dimensional changes in composition and density by seismology

seismic tomography

how is the shape of earth affected by its rotation

the equator is further from the center of the earth than the poles

which of the following materials would cause the greatest gravity anomaly

metallic ore

a ______ occurs when an iron-rich fluid in the core is electrically charged and flowing, which generates a magnetic field

geodynamo

______ are responsible for the heat generated in the interior today

short-lived radioactive isotopes

why is conduction not an efficient way to move heat through most of the earth

rocks are poor conductors of heat

what physical property of continents makes them difficult to subduct

low density

which process is responsible for earths magnetic field? In which layer does this process occur

convection; outer core

which of the following factors contributed toward the early increase in temperature in the earths interior

impact from planetesimals

If the outer core is cooler than the inner core, why is it in a liquid state

it is under less pressure than the inner core

The measurement of ocean depth and the topography of the ocean floor are known as _______

bathymetry

which of the following groups contains all three major topographic provinces oceanographers use to define the seafloor

continental margins, mid-ocean ridges, and deep-ocean basins

what are the two types of continental margins

passive and active

which of the following is associated with a passive continental margin

no tectonic boundaries nearby

which of the following is associated with an active continental margin

convergent boundaries

which region is surrounded by an active continental margin

pacific ocean

which of the following scenarios would likely result in the development of a passive continental margin

continental blocks rifting apart and becoming separated by seafloor spreading

the continental shelf is composed of what materials

basaltic crust

although many areas of the continental shelves are relatively featureless, there are some locations on the shelves that have received extensive glacial deposits and significant dissection by streams. How would this have been possible

the sea level dropped during the last glacial episode because water was stored in large ice sheets, exposing the shelves

Which of the following will mark the furthest extent of a continent

lowest part of continental slope

what is the definition of turbidity current

submarine landslide

which part of a passive continental margin is built up by repeated deposition from turbidity currents

continental rise

submarine canyons found cutting into the continental shelf and slope are believed to have been created ______

by rivers during the ice age

What is the definition of subduction erosion

sediment and rock are scraped off the bottom of an overriding plate and transported into the mantle by a descending plate

where is the deepest place on earth

challenger deep

along which tectonic boundary are deep ocean trenches found

convergent

volcanic island arcs are found near which features on the seafloor

deep ocean trenches

what is the source of flood basalts associated with oceanic plateaus

the melting of the head of a mantle plume

volcanic islands such as the Hawaiian islands form as a result of _______

mantle plumes

submarine volcanoes, called _______ may rise hundreds of meters above the surrounding seafloor

seamounts

where do rift valleys form along the oceanic ridge system

along the axis of some ridge segments where the rift is down-faulted

what rock would you expect to find associated with a mid-ocean ridge

basalt

what generates the magma necessary for seafloor spreading

partial melting

which of the following materials or features are not found at mid-ocean ridges

deep submarine trenches

the oceanic crust is composed almost entirely of _____ rocks that are underlain by _____ rocks, which makes up the lithospheric mantle

mafic; ultramafic

the sheeted dike complex is layer _____ of the ocean floor

3

which of the following is not an example of a continental rift

Appalachia, united states

thermal springs known as _____ are often associated with oceanic ridges, where hot water containing dissolved minerals gushes from the seafloor

black smokers

which process, common near black smokers, uses hot water circulating through the crust to alter olivine and pyroxene into chlorite and serpentine

hydrothermal metamorphism

why do mantle plumes tend to concentrate beneath supercontinents such as Pangea?

A large landmass acts as an insulating blanket to trap heat in the mantle

most mountain ranges are the result of _____ stress

compressional

Which of the following terms describes the increasing downward force on basal rocks as a mountain continues to grow

gravitational collapse

How would the angle of subduction of a tectonic plate influence the location of a volcanic arc

the steeper the angle, the further the arc would form to the trench

In which location on a continent would one be likely to find young mountain belts (less than 100 million years old)

along the margins of the continent

which of the following regions of a subduction zone is characterized by thick sequences of relatively undeformed sedimentary rocks

forearc region

put the four regions of a subduction zone in order from the convergent boundary landward toward the continental interior

deep-ocean trench, forearc region, volcanic arc, back-arc region

which factor(s) will most influence the depth of deep-ocean trenches

temperature and density of the plate

the Cascadia subduction zone off the coast of Washington and Oregon famously lacks a well-defined deep-ocean trench. Why might this be the case

there is a shallow angle of plate subduction as well as large quantities of sediment infill

How does the angle of subduction affect the dimensions of the forearc basin

steep angle of subduction leads to a narrow forearc basin

what is the source of the sediments in a forearc basin

continental sediments and pyroclastic materials

If a back-arc basin is associated with a volcanic island arc, what tends to develop there

long linear sea

if a back arc basin is a region related to a subduction zone, how can such an extensional basin form near a boundary defined by compression

trench rolls back as the old, dense subducting plate sinks

which of the following is an example of a volcanic island arc

Aleutian volcanoes

In ocean-continental convergence, a volcanic arc is created on the _____ and is the result of _____ rising up from a subducting plate

continental plate; magma

a ______ will form as sediment collects between the accretionary wedge and the volcanic arc

back-arc basin

a divergent boundary will be characterized by what feature

a rift zone

which of the following locations is a remnant of a forearc basin

great valley CA

what is an accretionary wedge

sediments and ocean crust fragments being scraped off a subduction plate

which type of volcanic material will dominate the eruptions along a continental volcanic arc

mafic lavas

a _____ is a crustal fragment that has been transported by plate tectonics and has adhered to an overriding plate

terrane

which of the following locations is composed largely of accreted terranes

california

what is a suture

the zone where two continents are welded together

as India is colliding with Asia, the margin of Asia is experiencing significant deformation. What is happening to the rocks that are being deformed

they are being displaced to the southeast to make up southeast asia

put the three orogenic events of the Appalachian in order from oldest to youngest

taconic, acadian, alleghanian

which of the following describes the events of the taconic orogeny

closing of the marginal sea caused a volcanic arc to be thrust over the continent

which of the following statements best characterizes the geology of western north America, starting in California and extending through British Columbia and up into Alaska

geologically distinct, microcontinent-sized fragments and terraces accreted to the continent

what are fault block mountains

mountains formed through crustal extension and normal faulting

which US region is made up of a series of high-angle normal faults producing nearly parallel mountain ranges

basin and range province

which of the following is a real-world example of isostatic adjustment

rebound of the landmass around hudson bay after glacial ice sheets have retreated

why would geologic mapping be difficult in an area dominated by accreted terranes

each terrane is geologically distinct, but also highly deformed

_____ is the downslope movement of rock, regolith, or soil under the direct influence of gravity

mass wasting

what term is commonly used to describe a sudden event in which large volumes of rock move down steep slopes

rockslide

which of the following locations would be most likely to see large-scale, rapid mass wasting

the rocky mountains

which of the following factors does not influence mass wasting

geologic age

stream valleys are produced through combined effects of mass wasting and running water. If running water alone were responsible for creating stream valleys, how would they appear

narrow valleys with vertical walls

which region would be most likely to produce a catastrophic landslide

steep, geologically young mountains

what is the controlling force of mast wasting

gravity

a _____ is not the sole cause of a mass wasting event, but the last of many causes that initiate the downslope movement of materials

trigger

which of the following scenarios would lead to a mass wasting event due to an over steepened slope

construction of buildings on slopes

what is the angle of repose

the steepest angle at which a material remains at rest