A rocks texture refers to
The size shape and arrangement of the mineral components
The most important factor in determining ingenious rock texture is
The rate of cooling of the Magma
Bowens reaction series shows
When minerals crystallize first as a magma cools from liquid to a solid
Magma with high viscosity
Have a high resistance to flow
A dike forms when
Lava cools on its way to the surface in a large vertical crack in the host rock
The viscosity of magma increases with
Increase amounts of silica
Which of the following is the most felsic rock
Granite
A phaneritic texture is mostlikelyto develop in
Plutonic rock
A porphyritie texture is created
when magma is erupted after spending time slowly cooling in a magma chamber
A ______ texture represents a single, long period of cooling and crystallization
phaneritic
Pahoehoe flows are found closer to the vent because
the lava is hottest near the vent
Explosive eruptions are more likely when
temperature is intermediate and gas content is high
Shield cones form from
mafic lava because it is very fluid and spreads into thin sheets
Partial melting is a process that
allows some minerals to melt before others
The presence of water in a rock will
decrease the melting point
Rhyolite is an uncommon rock because
felsic magmas have a high viscosity and crystallize before they reach the surface
Gabbro has larger crystals than basalt because
the magma cooled more slowly
A magma produced from partial melting will be
more felsic than the source rock because refractory minerals are left behind
A composite cone is made of
alternating layers of pyroclastic material and lava flows
Lava domes are created from
felsic lava
Flank eruptions are associated with
shield volcanoes erupting fluid magma
Which one of the following types of weathering will change the chemical composition of a rock
oxidation
Frost wedging would be most effective in
mid-latitude regions where temperatures hover around 0�C (32�F) during certain seasons
When granite decomposes, K-feldspar is chemically weathered to form
clay
A well-sorted sediment is one in which
all of the grains are the same size
Chemical sedimentary rocks are classified based on
mineral composition
The weathering reaction dissolution
leaves no solid products behind
K-feldspar is easily destroyed through
hydrolysis
Hydrolysis is most effective on
granite because it contains a large amount of feldspars
Which of the following minerals is most susceptible to the weathering process of oxidation?
olivine
You can differentiate between arkose and quartz sandstone based on
the sorting of the sediment in the rock
Conglomerate and breccia contain
gravel size grains
Rock Salt and Rock Gypsum form through the process of
evaporation
When layers of sediment are deposited by a moving current of wind or water
they form cross-beds
Clay minerals formed from granite bedrock illustrate which kind of weathering
chemical
Which kind of sandstone contains abundant K-feldspar, suggesting that the sand was derived by weathering and erosion of granitic bedrock and was not transported far
arkose
Flint, chert, and jasper are microcrystalline forms of ____
quartz (SiO2)
Which sedimentary rock would you expect to form from an ancient lake bed?
shale
What is special about the environment in which plant matter accumulates to eventually form coal?
It is oxygen deficient
If a magma has a high temperature and a low silica content, it's viscosity will be
low
What is the approximate minimum depth and temperature required for metamorphism?
10 kilometers, 200�C
Foliation occurs as a result of
pressure that breaks some of the bonds between mineral ions and causes the unbonded ions to migrate and recrystallize in areas of lower pressure
Gneiss can be distinguished from other metamorphic rocks by
its dark and light mineral bands
The type of metamorphism that occurs when rocks are caught between two converging plates in a collision zone is
regional metamorphism
Which of the following best describes the conditions of contact (thermal) metamorphism
Pressure is confining only, the rock is in the upper part of the crust and heat is supplied from a nearby magma body
A shale is metamorphosed into schist. This means it was metamorphosed through
regional metamorphism
If a horizontal layer of solidified lava lies between two horizontal sedimentary strata, the principle by which the relative ages of each of these layers could be determined is
the principle of superposition
According to the Principle of Cross-Cutting Relationships, if a dike is found cutting across sedimentary layers, the reasonable conclusion would be that
the dike is younger than the layers
The half-life of a radioactive isotope is
the time required for half the parent isotope to decay
The general term unconformity refers to
an erosion surface between two layers of rock where rock layers are missing
According to the principle of inclusions, if a rock is found embedded within an igneous pluton, the reasonable conclusion would be that
the rock is older than the pluton
Rocks in which ductile deformation occurs
remain in their deformed shape when the stress is released
brittle strain
is when a rock breaks
a fold in a rock
indicates that the rock layers experienced ductile strain
Compressional stress causes
folding
Normal faults are commonly found near
divergent plate boundaries
In an anticline, the limbs of the fold dip
away from each other
The type of fault most commonly found in transform plate boundaries is a
strike-slip fault
A normal fault occurs as a result of
tensional stress, and the hanging wall moves down relative to the footwall
A graben is characterized by
a hanging wall block that has moved down between two normal faults
A thrust fault is best described as
a low-angle, reverse fault
A shale is metamorphosed through Regional Metamorphic event, where two continents have collided. The resulting metamorphic rock will be
schist
A quartz sandstone is metamorphosed when a magma moves up into the crust. The resulting metamorphic rock will be
quartzite
The focus of an earthquake is
the precise underground location at which rocks begin to rupture or shift
The Mercalli Intensity scale differs from the Richter and Moment-Magnitude scales because
it is a descriptive scale, which assigns a magnitude based on observed damage, rather than assigning a magnitude based on energy released
The Richter Scale is a logarithmic scale, which means
each successive number corresponds to a ten-fold increase in the wave-amplitude traced on a seismogram
Liquefaction is a process where unconsolidated sediment with some cohesiveness
begins to flow like a liquid, with no water added
Tsunami are caused by
a large, rapid, vertical displacement of the seafloor during submarine faulting
The vast majority of earthquakes are concentrated
at plate boundaries
When an earthquake occurs, the first waves to arrive at a seismograph are the
p-waves
An earthquake's epicenter is the point
on the Earth's surface directly above the quake's focus
P waves and S waves are two types of
body waves
P-waves travel through the earth by
compression and expansion
To locate the epicenter of an earthquake, a seismologist must determine all of the following EXCEPT
the depth of the earthquake and the type of fault from which it originated
Which of the following statements concerning P waves is NOT true?
P-waves stop when they move into liquids
Oceanic crust is
very homogeneous and made dominantly of basalt
Changing the speed of a P-wave makes the wave
refract
The epicenter of an earthquake is always
none of the above
When rocks break or a fault moves, energy is released in the form of
seismic waves
The lag between P- and S-wave arrival times can be converted to
the distance between the earthquake epicenter and the seismograph station
An important aspect of seismic waves is that they have different time gaps on seismograms from different locations. Why would a seismogram recorded closer to the epicenter have the P and S wave arrivals closer together than on a seismogram from farther aw
The arrival time of any wave is based upon its speed. P waves are faster, so they "pull away" from S waves with increasing distance from the epicenter
The continental shelf is
continental crust that is submerged under ocean water
Passive continental margins
have developed from divergence
New oceanic crust and lithosphere are formed at
divergent boundaries by submarine eruptions and intrusions of mafic magma
seamounts
are volcanoes that form on the ocean floor
Old oceanic lithosphere typically experiences what type of subduction and at what angle?
Spontaneous subduction; steep angle
An earthquake occurs in the north Pacific ocean near the coast of Alaska. Which of the following combinations are most likely to generate a tsunami?
compressional stress, vertical movement
An earthquake of magnitude 8.5 is how much more powerful than one of magnitude 5.5?
1000 times
The Atlantic Ocean is a middle-aged ocean. During the next stage of development for the Atlantic, it will begin to look more like which of the following
Pacific Ocean