Exam #2 Earth and Geology

Which gas was erupted under Lake Nyos?

CO2

Which of the following is a possible reason for volcanism to end?

Change in tectonic setting

Which of the following is an example of volcano with low viscosity lava?

Columbia River Flood Basalts

What is the stress in a subduction zone?

Compression

What type of metamorphism leads to the rocks near a magma intrusion to have a higher metamorphic grade than the rocks further away from it?

Contact

What tectonic plates are the most likely to be found at a volcano forming boundary?

Continental - continental

At what boundary type do volcanoes form?

Convergent - subduction

On Figure 2, which principle allows you to say whether D is younger or older than A?

Cross-cutting relationships

A lab grown diamond is a mineral.

False

Adding vegetation is a potential trigger of mass wasting.

False

Folds form in brittle environments, and faults form in ductile environments.

False

Yellowstone and the CRBs are due to 2 different hotspots.

False

What magma composition does Yellowstone have?

Felsic

What type of volcano are the CRBs?

Flood basalt

What forms in ductile conditions?

Folds

What silica content and viscosity are associated with explosive volcanoes?

High Si, high viscosity

What silica content and viscosity are associated with Hawaii?

High Si, low viscosity

Folds form in what conditions?

High temperature and pressure

Which of the following is true for the principle of inclusions?

Inclusions are older than the rock they are found in

On Figure 1, which principle allows you to say whether I is younger or older than D?

Intrusions

On Figure 2, which principle allows you to say whether B is younger or older than A?

Intrusions

Two atoms of the same element which have different numbers of neutrons are called?

Isotopes

When mud on the flank of a volcano is mixed with melted glacier ice, what is the resulting mass wasting?

Lahar

Which Mount Rainier hazard has reached Tacoma in the past?

Lahar

What silica content and viscosity are associated with explosive Mount Baker?

Low Si, low viscosity

What silica content and viscosity are associated with the CRBs?

Low Si, low viscosity

What silica content and viscosity are associated with the Deccan Traps?

Low Si, low viscosity

What do volatiles do for volcanism?

Lower the melting temperature

What magma composition do the Deccan Traps have?

Mafic

What magma composition does Mauna Loa have?

Mafic

What rock type forms by increasing the temperature and pressure of a pre-existing rock?

Metamorphic

Which of the following is an example of volcano with high viscosity lava?

Mount St Helens

What would make a slope susceptible to failure during a ground motion event?

No trees Loose rock Loose soil Water-saturated pore spaces

Which principle tells us that a rock with a fossil of a T-Rex was deposited flat?

Original horizontality

What type of seismic wave can make people seasick?

Rayleigh

What type of metamorphism leads to rock layers at depth to have a higher metamorphic grade than the layers near the surface?

Regional

_ dating gives a rock age as younger than, or older than another, __ dating gives an actual age to a rock fragment.

Relative / Absolute

What is a sedimentary rock?

Rocks changed during the addition of intense heat and pressure.

What rock type forms by cementing rock and organic fragments?

Sedimentary

What type of volcano is found on Hawaii?

Shield volcano

What type of metamorphism occurs instantly?

Shock

What type of volcano is Mount Rainier?

Stratovolcano / Composite volcano

On Figure 2, which principle allows you to say whether B is younger or older than D?

Superposition

On Figure 2, which principle allows you to say whether C is younger or older than E?

Superposition

Which principle tells us that a rock with a fossil of a T-Rex is older than the rock above it?

Superposition

What is the stress in a mid-oceanic ridge?

Tension

What is the Cenozoic Era

The age of mammals

What was the Mesozoic Era?

The age of reptiles

What is strain?

The deformation of the crust

What is stress?

The force applied to the crust

The atmosphere of which of the following planetary bodies is the most similar to ours, with mostly Nitrogen?

Titan

A mountain range with high elevation, high peaks, and which is near a convergent boundary is most likely very young.

True

A snow flake is a mineral.

True

Dams are a potential trigger of mass wasting.

True

Each radioactive element has a specific decay rate.

True

Foliation is folding and alignment of minerals in a rock due to pressure.

True

Foliation is rock layers created during the deposition of material.

True

Glacier ice is a mineral.

True

Hazard maps exist for all known active volcanoes.

True

Hazard maps indicate all known hazards for a given region.

True

Intrusive metamorphic rocks cool inside the crust, and extrusive metamorphic rocks cool down at the surface.

True

Natural activity is a potential trigger of mass wasting.

True

Removing vegetation is a potential trigger of mass wasting.

True

The Appalachian Mountains are older than the Rocky Mountains.

True

The higher the magnitude of an earthquake, the more llikely it is to trigger ground movements farther away from the epicenter.

True

Volcanic eruptions are a potential trigger of mass wasting.

True

Wildfires are a potential trigger of mass wasting.

True

What does an unconformity represent?

a gap in time

What type of unconformity is shown here?

angular unconformity

What geologic structure is shown here?

dome

A mountain range with low elevation, a rounded summit, and which is away from a convergent boundary is most likely very young.

false

Once a mountain range is done forming, erosion stop

false

Which Lake Nyos hazard are volcanologists the most worried about?

gas

Which Mount Rainier hazard are volcanologists the most worried about?

lahar

Which Hawaii hazard are volcanologists the most worried about?

lava

What geologic structure is visible here?

normal fault

Atoms are made up of which of the following?

protons + electrons

Which of the following are volcanic hazards?

pyroclastic flows lava and gas earthquakes lahars

On Figure 1, which principle allows you to say whether C is younger or older than E?

superposition

On Figure 1, which principle allows you to say whether K is younger or older than F?

superposition

What are the 2 main types of seismic waves?

surface waves body waves

Hazard maps show the spatial extent of hazards.

true

Were the Columbia River Flood Basalts emplaced by the Cascade volcanoes?

yes

Which of the following is NOT true for a mineral?

1 mineral has only 1 color

We are dating a rock sample with a radioactive element that has a half-life of 50 Ma. 25% of the parent element is left. How old is the rock sample?

100 Ma

We are dating a rock sample with a radioactive element that has a half-life of 50 Ma. 6.25% of the parent element is left. How old is the rock sample?

200 Ma

We are dating a rock sample with a radioactive element that has a half-life of 200 Ma. 12.5% of the parent element is left. How old is the rock sample?

600 Ma

After 3 half-lives, how much of the parent element is gone?

87.5%

After 4 half-lives, how much of the parent element is gone?

93.75%

The least safe to build would be...

A large hotel on a hill with no trees

What is an igneous rock?

A rock made up of crystals cooled from lava or magma.

The safest to build would be...

A small house on a hill with many trees

Which is true of faunal succession?

Assemblages of fossils help give a number age to a rock layer

How are the lengths of time in the geologic time scale divided?

Based upon changes in life or large scale natural events.

How can we say that a world is currently geologically (volcanism and tectonics) active?

By witnessing changes on the surface By recording seismic waves on the surface By witnessing ongoing volcanic activity