Geology 1403 Exam #2
At which points on this graph is the magma under the highest amount of pressure and highest temperature?
1
Which site associated with Mount Rainier has the lowest hazard for pyroclastic eruptions?
1, the suburbs of Tacoma
Which of the numbers on this figure indicates typical continental conditions (regional metamorphism)?
2
Which location on this diagram would most likely record metamorphism along a subduction zone?
3
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
Shale is metamorphosed into three rock types: (1) a banded gneissic rock; (2) a rock with small mica crystals with a shiny aspect; (3) a very shiny rock with large mica crystals; and (4) a dull slate with cleavage. Which of the following lists these rocks in order of increasing metamorphic grade?
4, 2, 3, 1
On this figure of Bowen's Reaction Series, which mineral would crystallize last from magma?
4, K-feldspar
Which site associated with Mount Rainier has the highest hazard for lava flows?
4, the summit of the volcano
Which letter in this classification table indicates the position of granite?
A
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 is the best example of heat transfer by conduction?
A pan is placed directly on a burner.
Flood basalts influence life on Earth because
All of these choices are correct.
Gradational boundaries between different sedimentary rock types can form from:
All of these choices are correct.
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.
Sedimentary environments on land differ because of variations in
All of these choices are correct.
Some scientists think that Yellowstone could cause a future disaster because
All of these choices are correct.
What are some factors that could allow flood basalts to have high-volume eruptions?
All of these choices are correct.
What can occur in association with a thrust fault?
All of these choices are correct.
What causes the stress that forms joints?
All of these choices are correct.
What type of material likely composes this volcano?
All of these choices are correct.
What types of rocks would be common in a composite volcano?
All of these choices are correct.
What types of rocks would be common in the volcano in this figure?
All of these choices are correct.
Which of the following are hazards associated with scoria cones?
All of these choices are correct.
Which of the following commonly precede a volcanic eruption?
All of these choices are correct.
Which of the following does NOT match a sedimentary rock with a possible metamorphic equivalent?
All of these choices are correct.
Which of the following might a geologist look for in a rock hand sample to make interpretations regarding deformation and metamorphism?
All of these choices are correct.
Which of the following structures can be related to or can occur close to faults?
All of these choices are correct.
Which of the following environments is NOT a setting in which limestone forms?
All these are environments in which limestone forms.
Which number of this figure indicates transfer of thermal energy by conduction?
All these are transfer of thermal energy by conduction.
Which of the following are true of felsic magmas?
All these are true of felsic magmas.
Which of the following does NOT help define layers in some sedimentary rocks?
All these are ways that can define layers in sedimentary rocks.
Which of the following are processes that can occur in large magma chambers?
All these can occur in large magma chambers.
Fold and thrust belts
All these describe fold and thrust belts.
Which of the following processes could result in a felsic magma?
All these would result in a felsic magma.
Which letter in this classification table indicates the position of rhyolite?
B
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 letter in this classification table indicates the position of andesite?
C
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
The site on this figure that would most likely form a rock that is glassy with no volcanic ash is
C.
Which letter in this classification table indicates the position of gabbro?
D
In what site on this figure would you expect regional metamorphism?
D and 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.
What is the difference between foliation and lineation in metamorphic rocks?
Foliation is planar; lineation is linear.
Based on the image and your knowledge of metamorphic minerals, which of the following is true?
Garnet is diagnostic of moderate- to high-grade metamorphic conditions.
Which of the following is a correct statement about resources in sedimentary rocks?
Groundwater mostly resides in the pore spaces between grains and in fractures.
Why do rocks become stronger with depth in shallow levels of the crust?
Increasing confining pressure holds them together.
What does this welded texture indicate about the formation of this rock?
It formed from an explosive pyroclastic eruption.
What is the origin of the fissure on Mauna Loa?
It's the sheet like conduit to the magma chamber.
Which numbered feature on this figure formed by an explosive pyroclastic eruption?
Location 1, the Valles Caldera
Which of the following would be more likely during assimilation?
Mafic magma would melt felsic rocks that it comes in contact with.
How does dolostone form?
Magnesium carried by groundwater replaces some of the calcium in limestone.
Which of the following is NOT a reason why heat flow and gas output from a volcano tend to increase before eruptions?
Melting of snow caps dissolves large amounts of water into the magma.
Which era was unit 3 deposited in?
Mesozoic
Based on the map, what is true?
Metamorphic conditions were most intense in the center area and decreased toward the east and west
How does schistosity develop in a metamorphic rock?
Mica flakes line up in parallel orientation due to differential stress.
Which of the following factors helps magma rise toward Earth's surface?
None of these choices are correct.
Which of the following occurs during a continental collision, after any subduction has ended?
None of these choices are correct.
The relatively small volcanic feature that consists of solidified lava and some volcanic ash is
None these choices are correct.
How are fissures formed?
Pressure from magma pries open fractures in rock, and then magma fills the fracture.
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.
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.
How would the force and stress on the wooden pillar in this figure change if the stone weight was the same size but the wooden pillar were narrower?
The force would remain the same, but the amount of stress would increase.
Which of the following interpretations is consistent with the character and sequence of rocks in this figure?
The lower part of the section is consistent with deposition of marine layers over sand dunes.
What does this texture indicate about the formation of this rock?
The magma had abundant dissolved gas.
Which of the following is likely to be true about the left volcanic feature compared to the right one in this figure?
The magma has a higher viscosity.
What generally happens when subduction-derived magma encounters thick continental crust?
The magma interacts with the crust, forming felsic or intermediate compositions.
Which of the following indicates that a fault is present in the center of this photograph?
The rock layers are offset and terminated.
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 three missing parts of the sentence using the viscosity, composition, and resulting rock type.
This figure shows an eruption of high-viscosity (viscosity) magma that probably has a felsic or intermediate (composition) and would form pumice (resulting rock type).
Which of the following statements is NOT true about clastic sedimentary rocks?
To be called a sandstone, quartz must make up more than 95 percent of the grains.
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.
Which of the following is NOT something we can learn by studying geologic structures and metamorphic rocks?
We can learn information about all these by studying structures and metamorphic rocks.
A graded bed forms due to:
a gradual decrease in the strength of the current over time.
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 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
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
What type of eruption formed this flow-banded obsidian?
a viscous lava flow
What type of eruption formed this mottled rhyolite?
a viscous lava flow
Which of the following factors indicates a high risk for volcanic mudflows or lahars?
a volcano with a thick covering of snow or ice
Which of the following environments would likely have clasts smaller than sand?
a weak current
This photograph shows chalk. How is it formed?
accumulation of microscopic organisms composed of calcium carbonate
This photograph shows chert. How does it form?
accumulation of silica-rich organisms or mixing of seawater and groundwater
How is magma created at this continental rift?
addition of heat
Which of the following is NOT a way in which a volcano's history indicates the level of hazard it poses to nearby population centers?
age of the oldest volcanic layer present
Bedding in sedimentary rocks is defined by:
all of the characteristics listed.
Which of the following acts to keep a rock solid (instead of melting)?
an increase in confining pressure
The most common volcanic rock found in lava flows on composite volcanoes is
andesite.
This landscape of eroded fine-grained sedimentary rocks is known as:
badlands.
Hot spots in continental settings typically produce
basaltic lava flows or explosive calderas.
If bubbles cannot escape easily from a magma, the resulting eruption is likely to
be explosive.
Which of the following environments would most likely consist of sand and/or rounded cobbles?
beach at A
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 a sea
A single volcano may produce
both explosive and nonexplosive eruptions.
Which of the rock layers in this figure was most likely deposited in a shoreline environment?
both of the tan sandstones
Sediments with a large amount of sand are most likely at
braided river at C and delta at D.
Which of the following is most likely to occur at shallow crustal levels?
brittle deformation
Which of the following is NOT a hazard typically associated with scoria cones?
bulldozing of houses from their foundations
What is a main hazard of this type of volcano?
burning, building collapse, and suffocation from an eruption column and pyroclastic flows
The main hazard of an eruption that forms a large caldera is
burning, building collapse, and suffocation from an eruption column and pyroclastic flows.
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.
A sandstone containing mostly sand but mixed with rounded pebbles and pieces of shells indicates deposition:
by waves at the beach.
What type of product is being produced from material in these quarries?
cement
Volcanic mudflows can be detected remotely by monitoring
characteristic rumbling produced as they rush down valleys.
What data did geologists use to create this graph?
chemical analysis of minerals in metamorphic rocks
Which of the following does NOT correctly match a rock with a possible environment in which that rock forms?
coal - deep-sea organic-rich black shale
The most dangerous type of volcano is a
composite volcano.
What type of metamorphism would occur in this setting?
contact metamorphism
What is the typical setting for fold and thrust belts?
convergent plate boundaries
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
These sandstone beds are interlayered with dark marine shales. What is the most likely environment in which the sandstone formed?
deep-water turbidity currents
Which of these processes associated with regional metamorphism is most likely to cause foliation in a rock?
deformation
A very well-sorted sandstone with large-scale cross bedding indicates the sand was likely:
deposited by the wind in dunes.
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.
Which of the following features is probably the same age as fault 2?
deposits along the fault
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
What type of weathering is best expressed in this weathered limestone?
dissolution
Carbonate rocks exposed at the surface in wet environments will:
dissolve and weather readily.
What types of features are shown in this photograph of unmetamorphosed sedimentary rocks?
erosion of strong and weak layers
Compared to non-fractured rocks, the rate of weathering in fractured rocks of the same composition is
faster.
This igneous rock is
felsic and fine-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
What is the main type of eruption that formed the volcano in this photograph?
fluid lava flows
What does the texture of this rock indicate about its cooling history? The magma cooled
for a while at some depth and then rose to the surface where it finished solidifying.
Which of these attributes preserved in sedimentary rocks gives us the most information about past climates?
fossils
Which of the following changes in conditions indicates heating of the rock?
from A to B
Which of the following changes in conditions represents decompression melting?
from C to B
What is a path for magma as it solidifies at great depth and then is uplifted slowly toward the surface?
from D to C to A
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.
Which of the following is NOT a typical hazard posed to human-made structures by lava flows?
high winds
What type of stress could form the fault in this figure?
horizontal tension
Large shield volcanoes are associated with which plate tectonic setting?
hot spots
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
When were the rocks in this cross section folded?
in the middle to late Paleozoic
Minerals crystallize
in the opposite order they melt.
Which of the following sites would contain the finest grained sedimentary deposits?
lake at E
Which of the following igneous rocks has a texture consistent with a magma that cooled and solidified slowly at first, followed by more rapid cooling?
large, early formed crystals surrounded by smaller, late formed crystals
Which of the following features is younger than fault 1?
lava flow and granite
When fluid lava erupts onto the surface, it typically produces
lava flows.
What type of eruption formed the small volcano in this photograph?
lava fountain
What type of rock would you form in this coral reef?
limestone
Which of the magma systems shown is likely to contain mostly basalt?
locations A and B only
Which of the sites shown in this figure have decompression melting in an oceanic setting?
locations A and B only
An igneous rock rich in olivine and pyroxene is classified as __________ in composition.
mafic
As magma is generated along a subduction zone
minerals in the subducted plate release water, which lowers the melting temperature of the mantle material above.
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
To study an igneous rock with a phaneritic texture, a geologist would need
no special equipment.
A felsic igneous rock likely has all the following minerals except
olivine.
When melting forms magma
partial melting produces a magma that is more felsic than the source.
Which of these minerals would you be least likely to find in a sample of gabbro?
potassium feldspar
How does iron formation form?
precipitation from seawater early in Earth's history
The liquid-solid boundary on this graph slopes down and to the right because
pressure increases down in Earth.
A mafic igneous rock likely has all the following minerals except
quartz.
What type of metamorphism dominates a continental collision?
regional metamorphism
What type of metamorphism would occur in this setting?
regional metamorphism
What is a main hazard of this type of volcano?
relatively small pyroclastic eruptions caused by localized explosions or collapse
This image is demonstrating chemical __________ during metamorphism and deformation.
remobilization
What type of fault forms when the hanging wall moves up in relation to the footwall?
reverse fault
What type of fault is shown in this figure?
reverse fault
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 is shown in this photograph?
sandstone
Which of the following lists the four types of volcanoes shaped like hills and mountains?
scoria cone, shield, composite, dome
Which of the following matches a sedimentary rock with a possible metamorphic equivalent?
shale - slate
The boundary between these two different sedimentary layers is:
sharp.
The contact between the shale on the bottom of this sequence and the light-colored sandstone above it is:
sharp.
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
A broad and low volcano composed of basaltic lava flows is likely to be a
shield volcano.
What does the texture of this rock indicate about its cooling history? The magma cooled
slowly under relatively deep conditions.
Volcanic domes commonly are partially destroyed when
steep parts of the dome collapse and cause small pyroclastic flows.
What kind of structure is shown in this image?
strike-slip fault
Potentially explosive composite volcanoes are most common above
subduction zones.
What orientation of stresses is the simplest explanation for the structure shown in this figure?
tension from upper left to lower right
A welded igneous texture indicates that
the ash and pumice were hot and became compacted.
Imbricated clasts in this river means that:
the current flowed from right to left.
Fine-grained sediment would most likely be present at
the lagoon at B and deep seafloor at D.
Shield volcanoes have low slopes primarily because
the low viscosity of basaltic magma allows it to flow downhill for long distances.
Which of the rock layers in this figure was most likely deposited by sand dunes on land?
the lowest red sandstone
The higher the gas pressure builds in a magma
the more explosive an eruption it is likely to produce.
A cross bed forms due to:
the piling of sediment down the front of a dune or ripple.
Coarsely crystalline igneous textures indicate that
the rock cooled slowly.
Which of the following features is older than fault 1?
tilted layers
Which setting would be the most likely to contain sand deposits?
turbidity currents along a continental slope
Which of the following units was most likely deposited in the deepest marine water?
unit 5
What type of eruption formed the volcano in this photograph?
viscous lava and pyroclastic eruptions
