EAPS 100 Exam 1

Volcanoes that are associated with subduction zones are frequently associated with explosive volcanic eruptions. All of the following are qualities of subduction zone magmas that lead to this characteristic behavior except which one?

*** The magmas have an extremely low viscosity (meaning that they can flow with relative ease) The magmas evolve towards very high silica (SiO2) content The magmas have large amounts of water in them

What magma property listed below would not lead to explosive volcanic eruptions?

***Low viscosity (flows with relative ease) High viscosity (flows with difficulty) High gas content

The above photograph shows two groups of sedimentary rocks, one that is vertical and the other that is shallowly dipping. James Hutton observed this outcrop and realized that an enormous of amount of time was required to deposit sedimentary rocks, rotate them to a vertical orientation, erode them, and deposit new sedimentary rocks. This realization kicked off the modern efforts to quantify the history of the Earth. What do we call surface (outlined in white) between the two groups of sedimentary rocks?

Angular unconformity

Ionic bonding occurs when ______?

Atoms lose or gain valence electrons to make positively or negatively charged ions that can then bond

The process through which loose sediment becomes a rock is known as lithification. _______ is the process that occurs when fluids precipitate new minerals in the pore spaces between sedimentary clasts/grains and leads to lithification.

Cementation

Cooling a magma will tend to cause it to

Crystallize minerals

The above diagram shows how the number of parent and daughter atoms change through time during radioactive decay. Which of the following statements is true?

Daughter atoms accumulate as parent atoms decay

The organisms that produce shells made out of calcium carbonate are utilizing what component of seawater?

Dissolved ions

Which of the following areas has the smallest risk for a mass wasting (i.e., landslide/rock fall) event?

Flat Plain

What is the reason why faults tend to move intermittently (stick-slip behavior) instead of continuously?

Friction

In the above diagram of a river system where are most sedimentary clasts/grains produced?

Highest

Which part of a river system represents the area where sediment is being produced?

Highest elevation

What are the three main types of rock?

Igneous, metamorphic, sedimentary

Sandstone is a sedimentary rock largely composed of sand-sized sedimentary clasts/grains. Which of the following environments is not a place where you would expect sand to be deposited and eventually form sandstone?

The deep ocean far from any land

What feature would not make a fossil useful for determining relative geologic ages?

The species had a very small population

Continental collisions lead to the development of what type of topographic feature at the surface of the Earth?

A major mountain range

_______ is a rock formed from solidification of magma that forms during partial melting of the Earth's mantle? Please fill in the blank with the best answer choice.

Basalt

One by-product of burning fossil fuels to produce energy is the production of large quantities of which gas? Hint: Remember the photosynthesis-respiration/combustion equation.

Carbon Dioxide (CO2)

You observe the volcanic eruption above. Based on the shape of the mountain and the eruptive style, what tectonic setting are you in? (Steep, explosive)

Close to a subduction zone

Most plants and animals that have lived on Earth will make fossils after they die.

False

Why do faults move in discrete increments that produce earthquakes rather than continuously and smoothly?

Frictional Forces

Alfred Wegener's proposal for continental drift was rejected during his own lifetime (b. 1880, d. 1930) for which of the following reasons?

He did not have a explanation for how the continents had moved

Heating a magma will ________ crystallization and solidification into a rock. Please fill in the blank with the best answer choice.

Inhibit

What is the name for a mud flow that is composed of volcanic debris?

Lahar

On the above diagram of a river delta, where would you expect the smallest sedimentary clasts to be deposited?

Lowest elevation

Which of the following areas is most at risk for the development of a debris flow?

Mountainous

Seafloor spreading at mid-ocean ridges occurs when tectonic plates are ___________.

Moving apart

Which of the following is not a characteristic of minerals?

Natural *A random arrangement of atoms Solid Inorganic

Mid ocean ridges are underwater mountain ranges, where new oceanic crust is produced. If you were to dredge pieces of rock from a modern mid-ocean ridge, which of the rocks below would be most likely?

Pillow basalt

Minerals do not have

Randomly arranged atoms

The above image was taken of sedimentary rocks on a vertical cliff face. What type of fault is shown above?

Reverse Fault

A cooling magma begins to grow crystals. We can say that this magma is ________ the crystallizing mineral. Please fill in the blank with the best answer choice below.

Saturated with respect to

The Cambrian Explosion marks boundary between two great divisions of geologic time. What distinguishes sedimentary rocks that formed after the Cambrian Explosion from those that formed before the Cambrian Explosion?

Sedimentary rocks deposited after the Cambrian Explosion contain abundant animal and plant fossils.

You observe the sequence of sedimentary rocks in the above photograph. Using the principle of original horizontality, what can you infer about the history of this location?

The sedimentary rocks have been rotated from their original orientation.

A diamond (C) mined from a kimberlite is a mineral.

True

Which of the following is NOT an effective way to monitor for volcanic eruptions?

Use GPS to assess whether the volcano is inflating or deflating Monitor the composition of gases emitted from the volcano Monitor earthquake activity near the volcano *Monitor the water level in rivers near the volcano

The above photograph shows a mountain composed of sedimentary rock. The principle of lateral continuity allows you to assume that a single layer represents ________ as you trace it across the photograph.

approximately the same period of time

Subduction zones are places where oceanic crust is ___________. Please fill in the blank with the most appropriate answer choice.

pulled back into the Earth's mantle

Seafloor spreading at mid-ocean ridges is a mechanism that produces new oceanic crust. This process also allows adjacent tectonic plates to __________.

move apart

In order to sequester organic carbon in sediments at the bottom of the ocean, production of organic carbon through _________ must be greater than consumption of organic carbon through ________. Please fill in the blanks with the best answer choice.

photosynthesis; respiration

How would you characterize this volcano based on its shape and eruptive style? (Steep, Explosive)

A composite volcano

Which of the following is not a mineral?

A cubic zirconia (ZrO2) crystal grown in a laboratory

The point where oceanic crust begins sinking in subduction zones is marked by what type of topographic feature?

A deep canyon known as a 'trench'

In what tectonic setting might you find many reverse faults?

Convergent boundary

Which of the following best describes the force that drives plate tectonics?

Plates are pulled by oceanic crust that is metamorphosed into very dense rock during subduction

In the above photograph is the fault older or younger than the sedimentary rocks?

Younger

Lava flows, pyroclastic flows, and lahars are all different types of volcanic hazards. All of these hazards will ________ to minimize their gravitational potential energy. Please fill in the blank with the best answer choice.

flow downhill

Earthquakes produce three types of waves: p-waves, s-waves, and surface waves. Which of these waves causes the most ground motion and consequently the most damage during earthquakes?

surface waves

One by-product of burning fossil fuels for energy is the release of ________. Please fill in the blank with the best answer choice.

(carbon dioxide)

All of the following, except which answer choice, might indicate that magma is moving beneath a volcano?

***Several consecutive sunny days Inflation of the volcano Lot's of small earthquakes A change in the composition of gases emitted from the volcano

You encounter a sedimentary outcrop composed of conglomerate like the one shown in the above image. Which of the following is NOT a reasonable depositional environment for it to have formed?

*A deep marine setting far from any exposed land Within or adjacent to a major river Close to sea cliffs on an ancient shoreline Near the mouth of a major river

If you see a sequence of sedimentary rocks that changes from bottom to top: 1) conglomerate, 2) sandstone, and 3) limestone containing marine fossils, what is a plausible sequence of ancient depositional environments for that area?

1) River bed, 2) Beach, 3) Reef

Which of the following is least likely to trigger a mass wasting event from a steep slope?

A drought

Geological shortening during collisions between continents frequently leads to what topographic feature?

A mountain range

Which of the following locations would be at most risk of being damaged by a lahar?

A town adjacent to a stream near a volcano

Using the figure above, please answer the following question. When did the magmatic dike labeled 3 intrude the sequence?

After deposition of layer 2, but before deposition of layer 4.

Clastic rocks are distinguished from crystalline rocks in that they are composed or weathered bits of rock (clasts) that have been transported as sediment and deposited in a location that is different from where their constituent rocks formed. What is one feature of clastic rocks that you could use to distinguish them?

Clastic rocks are typically composed of rounded clasts

Coal is a sedimentary rock composed of organic matter and frequently contains plant fossils. Which of the following statements can we infer to be true about the depositional environment in which coal formed?

Coal was originally deposited in a biologically productive terrestrial ecosystem.

Is the volcano pictured above a composite or a shield volcano?

Composite

The Earth's mantle is composed of a rock called peridotite. It can begin melting through which of the following processes?

Decreasing pressure, while keeping temperature constant

Samples of the Earth's mantle are brought to the Earth's surface through rare volcanic eruptions. One example of this process are kimberlite eruptions, which erupt from deep in the Earth's interior and can breach the surface with extremely high eruption velocities. We have studied these type of volcanic eruptions in detail because they also transport the mineral _________, which only forms at extremely high pressures, to the Earth's surface. Please fill in the blank with the best answer choice.

Diamond

What process causes the Hawaiian islands to go from high volcanic mountains to very low-lying, small islands over long periods of time?

Erosion

The Alaska volcano observatory is one of the largest observatories in the United States, despite the fact that Alaska does not have any major cities adjacent to a major volcano. Why is so much effort put into monitoring Alaskan volcanoes?

Explosive eruptions can disrupt international air travel and Alaska lies along a common flight path between North America and Asia

Is the following statement true or false? The remains of most plants and animals eventually form fossils.

False

Which process typically leads to the concentration of elements like gold, silver, and copper into economically viable deposits?

Hydrothermal activity around crystallizing magma

You encounter a sandstone that is filled with the fossil bones of an organism that lived on land. What is a reasonable depositional environment for this sedimentary rocks?

In an ancient shallow marine setting near an ancient reef *Within or adjacent to an ancient river Near a an ancient, submerged mid-ocean ridge An ancient deep marine setting far from any exposed land

Chemical weathering is a major process during which rock is broken down through chemical reactions and dissolved ions are incorporated into natural waters. Which of the following parameters will lead to increased chemical weathering if all other variables are kept the same?

Increasing surface area

The above limestone contains fossil shells from marine organisms. What is not a reasonable inference about the environment in which this sedimentary rock was originally deposited?

It was originally deposited high in the mountains.

Plate tectonics modulates Earth's climate through all of the following processes except which one?

Leading to uplift and weathering during continental collisions Changing the amount of volcanic gases that are emitted into the atmosphere Changing the distribution of land and water between different latitudes as the continents move ***Burning fossil fuels

Which process leads to the production of magma at mid-ocean ridges during the process of seafloor spreading?

Lowering the pressure that the uppermost part of Earth's mantle experiences as it flows upward between two tectonic plates that are moving apart.

Which of the following processes best describes how magmas are produced in subduction zones?

Lowering the temperature of the mantle's melting point by adding water from the subducted oceanic crust.

Each letter in the above diagram represents a species and the adjacent line represents the period of time it was present on Earth before it speciated or went extinct. Use this information to determine which of the following sedimentary rocks is the oldest.

Lowest

Use the labels on the above cross section of a delta and associated sedimentary deposits to answer the following question. Where would you most likely find sedimentary deposits composed of the smallest clasts/sedimentary grains?

Lowest

You walk up to this outcrop of sedimentary rocks. You know from previous observations that they have not been rotated or overturned. Using the principle of superposition, which of the labeled layers is the oldest?

Lowest

Using the principles of original horizontality, lateral continuity, superposition, and cross cutting relationships, please determine the oldest labeled rock unit in the above photograph?

Lowest elevation

Which of the following is a line of evidence used to support the idea of seafloor spreading?

Magnetic striping on the seafloor The thickness of sediment on the seafloor increases away from mid-ocean ridges Evidence for recent basaltic eruptions at mid-ocean ridges

What process leads to partial melting of the Earth's mantle and the production of large volumes of basaltic magma at mid-ocean ridges?

Melting triggered by decompression as the Earth's mantle flows upward

What is the key process that causes the ocean crust to be pulled into the Earth's mantle?

Metamorphism transforms the basalt that forms ocean crust into a rock that is more dense than the Earth's upper mantle. This transition pulls oceanic crust downward as it sinks.

The unit cell leads to all of the following mineral properties except which one?

Mineral size

We now use radioactive decay to determine the age of geological materials. What is one feature of an ideal material for radiometric dating?

No initial daughter isotope when the material formed

Do volcanoes that dominantly erupt basaltic magma tend to pose an acute threat to human life?

No, people can typically get out of the way of lava flows. However, infrastructure might be damaged.

The above fault separates several sedimentary layers. Using the information from the video segments, how would you classify this fault? Hint: Identify the orientation of the fault, the footwall and hanging wall, and the sense of separation of sedimentary layers across the fault.

Normal fault

The San Andreas fault marks a transform boundary between the North American and Pacific tectonic plates. Los Angeles lies to the west of this fault and is part of the Pacific plate. Based on the lecture materials, where will Los Angeles be transported over the next ~50 million years?

Northwest towards Alaska

The above image shows all of the different tectonic plates (the boundaries are shown by dark blue and brown lines). Which location is least likely to experience a major earthquake? Note: I'm not asking whether a location has 0% chance of an earthquake, only the location that is least likely to have an earthquake.

Not on boundary

The process of seafloor spreading creates which type of crust?

Oceanic crust

Which location would be the safest place to build a house on the Big Island of Hawaii. Remember, this island has several active volcanoes that produce basaltic lava flows?

On a ridge on a non-volcanically active part of the island

Oil is composed of organic matter that has been buried in a sedimentary sequence and has experienced elevated temperatures during lithification. Which organism produced the organic matter that goes on to make oil?

Plankton

Coal is composed of fossil organic matter and is used as fuel for many of the power plants in the USA. From which organisms did this organic matter originate?

Plants

Coal is produced from burying organic matter in sediment and exposing it to high temperatures and pressures during lithification and, sometimes, metamorphism. Which types of organisms produced the organic matter that typically produces coal?

Plants

Which type of bedrock will lead to the most severe ground shaking during an earthquake?

Schist (a type of crystalline metamorphic rock) Granite (a type of crystalline igneous rock) *Unconsolidated sediment (a future sedimentary rock) Gneiss (a type of crystalline metamorphic rock)

Since one continent cannot easily sink beneath another continent when two continental plates collide they accommodate the differential motion between them through the process of 'shortening'. This process is similar to when the hood of a car is smashed in a wreck, leading to a shorter total length of the car. Which of the following is not a mechanism through which geological shortening occurs?

Seafloor spreading

What is the most common class of mineral within the Earth's crust? Hint: Remember the most common elements in the Earth's crust.

Silicate Minerals

What are the two most common elements in Earth's crust?

Silicon (Si) and Oxygen (O)

Diamonds are made from carbon with an isotopic signature that is consistent with an origin as ancient life-forms. What process could have brought organic carbon deep into Earth's interior to provide the carbon needed to create diamonds?

Subduction

Explosive volcanism occurs most commonly in which tectonic setting?

Subduction zones

Which type of seismic wave is most damaging to human infrastructure?

Surface waves

Transform plate boundaries occur in areas where ____________.

Tectonic plates are moving past one another horizontally.

In which of the following locations are sedimentary clasts likely to be deposited and preserved to form sedimentary rocks?

The bottom of the ocean

Hotspot volcanism typically makes linear chains of volcanoes that get progressively younger in one direction. What would best describe the orientation of these features?

The chain of volcanoes lies parallel to the direction of motion for the tectonic plate on which they are built

Alfred Wegener proposed that the continents had once been joined into a super continent and then drifted apart. Which of the following was a line of evidence that he used to make this proposal?

The coastlines of continents look like they fit together in the past. Fossils of certain species seem to form continuous habitat zones if continents were once joined Locations where there is evidence for tropical or glacial environments could be restored to low and high latitudes, respectively, if the continents were once joined together and had drifted apart

When a continent is pulled into a subduction zone it will __________?

The continent will resist being pulled into the Earth's deep interior because it is composed of rocks that are much less dense than the rocks that compose Earth's mantle.

The above photograph shows a vertical magmatic dike cutting across horizontal sedimentary layers. Which of the labeled rocks is the youngest based on the principle's of superposition and cross cutting relationships?

The dike

The 'Cambrian Explosion' occurred between 541-519 million years ago. What happened during this period of time?

The first macroscopic (things that you could see without the aid of a microscope) animals evolved

We now use radioactive decay to determine the age of geological materials. Which of the following is NOT a feature of an ideal material for radiometric dating?

The material incorporated a large amount of parent isotope as it formed Daughter isotopes cannot easily move out of the material after radioactive decays occur *The material incorporated a large amount of daughter isotope as it formed

Magma is dominantly produced in subduction zones through which of the following processes?

The melting point of the mantle is lowered by the addition of water released as the sinking oceanic crust undergoes metamorphic reactions

Researchers have documented that magnetic minerals within the seafloor form zones that sometimes point toward the modern north pole and sometimes point toward the modern south pole. These zones form linear belts parallel to mid-ocean ridges. Which of the following is an observation regarding these zones that supports the idea of seafloor spreading?

The zones are symmetrical about the mid-ocean ridge

Continental collisions occur when continents are pulled into subduction zones. Why aren't continents pulled into the Earth's mantle like oceanic crust?

They are composed of rocks that are less dense than the Earth's mantle.

Locations where tectonic plates slide past one another along a vertical plane are known as what type of plate boundary?

Transform Boundary

Examples of mechanical weathering?

Tree roots growing into a crack within a cliff and splitting rock Sand carried in wind abrades a cliff face Ice expanding in a crack and wedging a rock off of a cliff

We now think that plate tectonics is largely driven by 'slab pull', meaning that the ocean crust that is metamorphosed into very dense rock during subduction pulls the other tectonic plates as it sinks.

True

The smallest repeatable unit in a crystalline sold is known as the _________? Please fill in the blank with the best answer choice.

Unit cell

What process is constantly removing material from mountain ranges? Hint: Think back to earlier in the course.

Weathering and Erosion

You work at the a volcano observatory. Over the past several days you have monitored GPS data indicating that the volcano is inflating. Over the same period of time you have monitored numerous small earthquakes. Another scientist at the observatory reports that the gases emitted from several hot springs have changed to different chemical compositions. Do you recommend that the government evacuate the towns that are adjacent to the volcano?

Yes, the risk of eruption is elevated

Geologists think that hotspots form over what type of feature?

a 'plume' of hot material that has risen from deep within the Earth, potentially from the boundary between the Earth's mantle and core

A river requires _______ to transport large pieces of rock (i.e., sedimentary clasts) when compared to smaller clasts. Please fill in the blank with the best answer choice.

faster flowing water

The thickness of sedimentary rocks on the seafloor _________ with distance from mid-ocean ridges. This observation indicates that the seafloor gets progressively older with distance from the mid-ocean ridge and is one of the lines of evidence for seafloor spreading. Please fill in the blank with the most appropriate answer choice.

increases

Which of the following locations on the surface of the Earth has the lowest gravitational potential energy? Hint: Where is most sediment ultimately deposited?

the bottom of the ocean