Geology Exam 2 Review
At which points on this graph is the magma under the highest amount of pressure and highest temperature?
1
Which of the numbers on this figure indicates low pressure/high temperature metamorphic conditions?
1
Which site associated with Mount Rainier has the lowest hazard for pyroclastic eruptions?
1, the suburbs of Tacoma
Which location on this diagram would result from burial to moderate depths accompanied by normal heating of rocks (regional metamorphism)?
2
Which location on this diagram would most likely record hot conditions deep within the continental crust?
4
Which of these conditions could form rocks that are partly metamorphic and partly igneous?
4
How much silica do mafic rocks contain
44-55%
The site on this figure that would most likely form a rock with large crystals is
A
Which of the following changes in conditions indicates heating of the rock?
A and B
Which of the following sites has volcanoes related to subduction? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.
A and B
Which of the following sites would have the most dangerous volcanoes? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.
A and B
Which of the following sites would most likely have composite volcanoes? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge
A and B
What is the difference between a joint and a fault?
A fault displaces the rocks on one side relative to another.
Which of the following is the best example of heat transfer by conduction?
A pan is placed directly on a burner.
What continent collided with North America during the Paleozoic to create the Appalachian Mountains?
Africa
If you were designing a rock that would be easily weathered, which of the following characteristics would it have?
All of these choices are correct.
Which of the following describes lineation?
All of these describe lineation
Which of the following environments is NOT a setting in which limestone forms?
All these are environments in which limestone forms.
A single volcano may produce
Both explosive and nonexplosive eruptions
The site on this figure that would most likely form a rock that is glassy with no volcanic ash is
C
Which of the following changes in conditions represents the main cause of melting beneath mid-ocean ridges?
C and B
Which of the following sites has volcanism related to a hot spot or divergent margin? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.
C and D
Which of the following sites would most likely have less dangerous volcanoes? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.
C and D
In what site on this figure would you expect regional metamorphism?
D and E
Which letter in this classification table indicates the position of basalt?
E
Which of the following correctly states how early crystallization affects the composition of a magma? Use the graph.
Early crystallization causes the MgO (mafic) content to decline in the magma.
For each figure, complete the two missing parts of the sentence using the type of volcano and type of eruption.
Figure A shows a scoria cone (type of volcano) that forms from a lava fountain (type of eruption). Figure B shows a shield volcano (type of volcano) that forms from eruption of basaltic lava flows (type of eruption). Figure C shows a composite volcano (type of volcano) that forms from eruption of lava and ash (type of eruption). Figure D shows a volcanic dome (type of volcano) that forms from eruption of viscous, felsic lava (type of eruption).
What is the difference between foliation and lineation in metamorphic rocks?
Foliation is planar; lineation is linear.
What does this welded texture indicate about the formation of this rock?
It formed from an explosive pyroclastic eruption.
Which numbered feature on this figure formed by an explosive pyroclastic eruption?
Location 1, the Valles Caldera
What makes mafic magma less viscous than felsic magma?
Mafic magma is both hotter and has less silica.
Based on the map, what is true
Metamorphic conditions were most intense in the center area and decreased toward the east and west
Which of the following are NOT differences between an eruption column and pyroclastic flow?
Pyroclastic flows form from a higher gas flux.
Which of the following choices is NOT true about magma chambers?
Rock walls of magma chambers can withstand the intense heat and not melt.
How does scoria differ from vesicular basalt?
Scoria has more vesicles.
Which of the following is common in lava flows associated with scoria cones?
Some scoria cones are not accompanied by a lava flow and vice versa and Some lava flows squeeze out near the base of the scoria cone.
What is typically occurring when magmatism occurs far away from plate boundaries?
Some type of thermal disturbance is occurring in the mantle.
Use this graph that relates temperature and pressure to answer this question. What is required if a rock in position B moves to position A on the graph?
Temperature would have to decrease.
In this section, a lower gray rock is successively overlain by beach sandstone, lagoon mudstone, and limestone. What is the best interpretation of what was going on?
The area was experiencing a transgression.
Which of these best describes the molecular conditions of a solid material, e.g, a rock in the upper mantle?
The atoms and bonds are vibrating.
What typically happens to the size, shape, and sorting of clasts as they are transported from steep mountains toward more gentle settings?
The clasts become more rounded.
Comparing these two photographs, which eruption has lower viscosity magma?
The fluid cascade of lava.
Minerals commonly recrystallize during metamorphism; what does this mean?
The minerals grow into larger crystals.
Which of the following indicates that a fault is present in the center of this photograph?
The rock layers are offset and terminated.
Which are true of faults?
These are all true of faults
Which of the following is NOT true of calderas?
They are produced by removal of easily eroded pyroclastic materials.
What is the best explanation for the shape of these clasts
They have been transported a significant distance.
For the volcanic eruption in this photograph, complete the two missing parts of the sentence using the type of volcanic feature and type of magma.
This figure shows a lava flow (type of volcanic feature) that forms from eruption of low-viscosity, mafic lava (type of magma).
For the volcanic eruption in this photograph, complete the three missing parts of the sentence using the viscosity, composition, and resulting rock type
This figure shows an eruption of low-viscosity (viscosity) magma that probably has a mafic (composition) and would form scoria (resulting rock type).
Which of the following are ways that viscosity affects gases in magma?
Viscous magma prevents gas from escaping easily.
The cross beds shown here indicate what about the environment the sandstone was deposited in?
Water/wind flowed from right to left.
a viscous lava flow
What type of eruption formed this mottled rhyolite
Which letter in this classification table indicates the position of granite?
a
Which of the following rock photographs depicts a felsic igneous rock?
a - brown and black mixture
A volcanic eruption occurring beneath an ice sheet is likely to cause
a hazardous flood.
Which of the following is least likely to be a volcano?
a hill capped by volcanic rocks
What type of eruption formed this felsic volcanic breccia?
a lava that broke apart while it flowed
An ophiolite is identical to
a newly formed segment of oceanic crust, except it contains an additional layer of sediment.
What type of eruption formed this unit composed of volcanic blocks and volcanic ash?
a pyroclastic eruption
If you were designing a rock that resisted weathering, which of the following characteristics would it have?
a quartz-rich rock
What setting was this sedimentary rock deposited in?
a quiet, deep water location
What kind of metamorphic rock is formed where rocks have been heated but not deformed?
a rock with metamorphic minerals but no foliation or lineation
Which of the following is a hazard but not a risk, according to the textbook?
a scoria cone that erupts hot molten fragments on an unpopulated Pacific island
The angular clasts typical of breccia indicate what about the distance of transport?
a short distance transport
Which of the following sites near a volcano might be relatively less dangerous?
a site on a ridge as opposed to a site in a valley
Which of the following factors makes a site near a volcano relatively more dangerous?
a site that is within a valley that drains the volcano
What type of eruption formed this flow-banded obsidian?
a viscous lava flow
Which of the following is the best indicator that a volcano might be very dangerous?
a volcano that contains andesite and welded tuffs
Which of the following factors indicates a high risk for volcanic mudflows or lahars?
a volcano with a thick covering of snow or ice
How does chalk form?
accumulation of microscopic organisms composed of calcium carbonate
How does chert form?
accumulation of silica-rich organisms or mixing of seawater and groundwater
This photograph shows chert. How does it form?
accumulation of silica-rich organisms or mixing of seawater and groundwater
Flood basalts influence life on Earth because
all of these
Identify the factor(s) that strongly influence the size, shape, and/or sorting of sedimentary clasts.
all of these
Some scientists think that Yellowstone could cause a future disaster because
all of these
What are some factors that could allow flood basalts to have high-volume eruptions?
all of these
What causes the stress that forms joints?
all of these
What types of rocks would be common in the volcano in this figure?
all of these
Which of the following are dangerous aspects of composite volcanoes?
all of these
Which of the following can we understand by studying sedimentary rocks?
all of these
Which of the following characterizes a continental rift?
all of these
Which of the following features are associated with a strike-slip fault?
all of these
Which of the following igneous rocks can be composed of fragments
all of these
Which of the following is characteristic of continental rifts?
all of these
Which of the following structures can be related to or can occur close to faults?
all of these
Horizontal shear stresses, like those pictured, may produce
all of these choices are correct
How could a rock at point C be melted?
all these
Which of the following are true of felsic magmas?
all these
Which of the following does NOT help define layers in some sedimentary rocks?
all these
Which of the following is NOT a way to form layers in a sedimentary rock?
all these
Fold and thrust belts
all these describe fold and thrust
The most common volcanic rock found in lava flows on composite volcanoes is
andesite.
What structural and metamorphic features form in a fold and thrust belt?
anticlines and synclines related to movement of thrust sheets over bends in thrust faults and cleavage
Composite volcanoes are so called because they
are composed of lava flows, pyroclastic material, and mudflows
This landscape of eroded fine-grained sedimentary rocks is known as:
badlands.
What types of rocks would be most common in the volcano shown in this photograph
basalt mostly formed in lava flows
Eruptions of scoria cones are commonly associated with
basaltic lava flows and lava fountains.
If bubbles cannot escape easily from a magma, the resulting eruption is likely to
be explosive.
This sandstone includes shells of marine creatures that live in shallow water. What is the most likely environment in which it formed?
beach next to sea
Which of these processes creates both physical and chemical weathering?
biological activity
Sediments with a large amount of sand are most likely at
braided river at C and delta at D.
Which of the following is NOT a hazard typically associated with scoria cones?
bulldozing of houses from their foundations
Which of the following is NOT a volcanic hazard made worse by being located along a river valley directly downhill from a volcano?
burial by falling ash
The rounded clasts in this sedimentary deposit were likely transported:
by a river
The large cross beds in these rocks indicate that the sediment was deposited:
by the wind or a water current.
At which of the sites shown in this figure would melting probably be caused by introduction of water into hot rocks?
c
In what site on this figure would you expect low pressure/high temperature metamorphism?
c
Which of the following is NOT a typical eruption style during the growth of a composite volcano?
caldera collapse
What type of product is being produced from material in these quarries?
cement
What type of rock would you form in this plant-rich swamp?
coal
Which of the following igneous rocks would be formed by the slowest cooling?
coarse granite
Which of the following is NOT a way in which volcanic domes are commonly destroyed?
collapse into emptied magma chambers below
A relatively large, symmetrical volcano that contains interlayered lava flows, pyroclastic deposits, and volcanic mudflows is a
composite volcano
The most dangerous type of volcano is a
composite volcano.
What is the difference between a dike and a sill
composition
This graph demonstrates how we can infer the tectonic setting of an ancient basalt using
crystalline texture.
Which of the following does NOT help define foliation in metamorphic rocks?
crystals that grow in a random orientation
Which environment is most likely to deposit a breccia?
debris flow
A sandstone with a pinkish or reddish color that is the result of oxidation of iron-bearing minerals indicates the sand was:
deposited on land and exposed to air.
What is a main hazard of this type of volcano?
destruction by moderately fluid lava flows that can flow far from the volcano
What type of deformation is shown in this photograph?
displacement
Which of the following is most likely to occur at deep crustal levels?
ductile behavior
What types of features are shown in this photograph of unmetamorphosed sedimentary rocks?
erosion of strong and weak layers
What type of eruption formed the volcano in this photograph?
eruption of viscous lava
This igneous rock is
felsic and coarse-grained.
What types of rocks would be most common in the volcano in background of this photograph?
felsic and intermediate lava flows
What types of rocks would be most common in the volcano in this photograph?
felsic and intermediate lava flows and tephra
Which of the following causes magma to be less viscous?
fewer silicate chains in the magma
What do the large, dark spots on this map represent?
flood basalt deposits
What is the main type of eruption that formed the volcano in this photograph?
fluid lava flows
Which of these attributes preserved in sedimentary rocks gives us the most information about past climates?
fossils
Which of the following changes in conditions represents decompression melting?
from C to B
How did the joints in this photograph form?
from cooling
The contact between the shale, which dominates the bottom part of this sedimentary sequence, and the sandstone, which dominates the upper part, is best described as:
gradational.
Because shales and siltstones are easily eroded, the areas where they are exposed typically:
have soft slopes and soil cover.
Breccias and conglomerates are most often created by __________ events.
high energy
What type of stress could form the fault in this figure?
horizontal compression
What is a main hazard of this type of volcano?
hot fragments thrown a short distance from the volcano
In which part of New England would you most likely find gneiss?
in New Hampshire and Maine where domes expose high-grade metamorphic rocks
In what environments does high pressure/low temperature metamorphism occur?
in a subduction zone or accretionary prism
Continental rifts have a diverse suite of igneous rocks associated with them because melting occurs
in the mantle and in the crust.
When were the rocks in this cross section folded?
in the middle to late Paleozoic
Prior to an eruption, the surface of a volcano may rise centimeters to hundreds of meters as a result of
injected magma inflating the mountain.
This igneous rock
is made of ash, pumice, and rock fragments
A mantle plume rises because
it is solid but less dense than material around it
What type of eruption formed the main volcanic features in this figure?
large pyroclastic eruptions
What type of eruption formed the small volcano in this photograph?
lava fountain
Which of these is most likely to be a biochemical sedimentary rock?
limestone
Hot spots in oceanic settings typically produce
lines or clusters of volcanic islands
Which of the magma systems shown is likely to contain mostly basalt?
locations A and B only
Where would you expect to find this rock in a caldera?
lower parts (well below the surface)
An igneous rock rich in olivine and pyroxene is classified as __________ in composition.
mafic
This igneous rock is
mafic and fine-grained.
Which environment is least likely to deposit a breccia?
meandering river
n the process of rifting to for an ocean divergent boundary, at what stage is metamorphism by hot water most prevalent?
mid-ocean rifting
Tuff and volcanic breccia are both composed of a variety of igneous fragments. Their classification as either felsic, intermediate, or mafic therefore depends on the
mineral content of each individual unit.
Large, angular clasts are most likely at
mountains at A and glaciers at B.
Floodplains are built of
mud and sand deposited by floodwaters.
Which of these volcanic hazards associated with Mount Rainier is the most dangerous to nearby population centers?
mudflows
In what environments does low pressure/high temperature metamorphism occur
near magma but at shallow levels
Which of the following statements is valid about the structural and metamorphic history of New England?
none of these
The relatively small volcanic feature that consists of solidified lava and some volcanic ash is
none these
Shale is a common sedimentary rock because:
one of the places clay is deposited is very widespread (the seafloor)
When melting forms magma
partial melting produces a magma that is more felsic than the source
Joints form __________ to the direction of __________ stress.
perpendicular; least
Breccias are __________ sorted.
poorly-
Which of these minerals would you be least likely to find in a sample of gabbro?
potassium feldspar
The liquid-solid boundary on this graph slopes down and to the right because
pressure increases down in Earth.
Which of the following is NOT a typical match between the type of eruption and resulting rock type?
pyroclastic flow - scoria
Why are the joints forming in these uplifted rocks?
reduced pressure
Lineation and foliation are most likely to develop when a rock is involved in __________ metamorphism.
regional
What type of metamorphism dominates a continental collision?
regional metamorphism
What type of metamorphism would occur in this setting?
regional metamorphism
What type of fault is shown in this figure?
reverse
This sandstone includes small rounded pebbles and was deposited far from the ocean. What is the most likely environment in which it formed
river
What type of rock would you form in this environment, showing a dried up lake bed?
rock salt and other evaporite minerals
What type of deformation is shown in this photograph
rotation
What types of rocks would be most common in the small volcanoes in this photograph?
scoria and other vesicular basalt
What type of stress could form the fault in this figure?
shear
What type or metamorphic feature/texture is created along the thrust sheets of a continental collision?
shear zones
Why does gabbro rather than basalt form in the deeper areas of a mid-ocean ridge system?
slower cooling at depth
What does the texture of this rock indicate about its cooling history? The magma cooled
slowly under relatively deep conditions.
When lava flows reach the ocean, they
solidify and add land to an island
Volcanic domes commonly are partially destroyed when
steep parts of the dome collapse and cause small pyroclastic flows.
Which of the following situations would result in angular clasts?
steep slopes in a mountain
Potentially explosive composite volcanoes are most common above
subduction zones.
What do fossils preserved in the rock record tell us about Earth's history?
that environments changed and the organisms that lived in them either evolved or went extinct
A welded igneous texture indicates that
the ash and pumice were hot and became compacted
A volcanic breccia texture indicates that
the rock broke apart as it flowed.
What is the main difference between conglomerate and breccia?
the shape of the clasts
A vesicular igneous texture indicates that
there was a lot of gas in the magma.
Many sedimentary rocks exposed in the Denver region are tilted at a high angle to the horizontal, indicating that:
they were deformed after they were deposited and lithified.
Sedimentary environments on land differ because of variations in
topography, local geology, and amount of water
Which of the following units was most likely deposited along an ancient mountain front?
unit 1
Volcanic domes grow from lava being injected into the interior of mounds of cooled lava and from __________ lava flows breaking out and moving down its flanks.
viscous
What type of eruption formed the volcano in this photograph?
viscous lava and pyroclastic eruptions
Which of the following igneous rocks would be formed by the fastest cooling?
volcanic glass
The uniformly-sized sand shown here would be described as
well sorted
How does rock cleavage develop?
when rocks are deformed under low to moderate temperatures
Using maple syrup as an analogy for magma, what do you do to your syrup to decrease its viscosity so that it flows more evenly over your stack of waffles?
you warm it up
