Geology test 2

How much silica do mafic rocks contain?

44-55%

In what site on this figure would you expect high pressure/low temperature metamorphism?

A and B

Identify the factor(s) that strongly influence the size, shape, and/or sorting of sedimentary clasts.

All of these choices are correct

Under what conditions was this rock likely deformed?

All of these choices are correct

What chemical processes can occur during metamorphism and deformation?

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.

Which of the following processes produce sedimentary clasts?

All of these choices are correct.

Flood basalts influence life on Earth because:

All of these choices are correct. (large volumes of flood basalts are erupted during a short time; eruptions can release large amounts of gas that cool the atmosphere; eruptions can release large amounts of gas that warm the atmosphere.)

Which of the following are true of felsic magmas?

All these are true of felsic magmas.

Which of the following activities is NOT used to monitor volcanoes?

All these are used to monitor volcanoes.

Which of the following is NOT a rock typically found within calderas?

Gabbro

A coarse-grained intrusive igneous rock composed mostly of feldspar and quartz is called

Granite

On this figure of Bowen's Reaction Series, which mineral would crystallize last from magma?

K-feldspar

The largest concentration of composite volcanoes on Earth is located along the

Pacific Ring of Fire.

How are fissures formed?

Pressure from magma pries open fractures in rock, and then magma fills the fracture.

This image is demonstrating chemical __________ during metamorphism and deformation.

Remobilization

The special geologic terms used to represent the direction of a horizontal line on an inclined surface (like in a fault) and the angle of that surface to the horizontal are

Strike and dip

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.

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 is NOT true about flood basalts?

They are fed from large interconnected composite volcanoes.

Which of the following is NOT a characteristic of a volcanic dome?

They are one of the largest types of volcanoes.

Which of the following are ways that viscosity affects gases in magma?

Viscous magma prevents gas from escaping easily.

What setting was this sedimentary rock deposited in?

a muddy place that sometimes dried out

What type of volcanic eruption is shown in this photograph?

a pyroclastic column

An ophiolite is

a sliced-off piece of oceanic crust that has been thrust onto the edge of a continent or island

Which of the following is the best indicator that a volcano might be very dangerous?

a volcano that contains andesite and welded tuffs

All the following are tectonic settings where large magma chambers can form except

above existing lava fields

Which of the following is a common metamorphic process?

all of these choices are correct

The main source of heat energy for Earth's interior is a direct result of

alpha decay, which is an unstable atom losing 2 protons and 2 neutrons

The most common volcanic rock found in lava flows on composite volcanoes is

andesite.

What type of structure is shown in this figure?

anticline

A fine-grained mafic igneous rock is called

basalt

What type of volcanic eruption is probably shown in this photograph?

basaltic lava flow

If bubbles cannot escape easily from a magma, the resulting eruption is likely to

be explosive

What type of metamorphic feature is shown in this photograph?

cleavage

A relatively large, symmetrical volcano that contains interlayered lava flows, pyroclastic deposits, and volcanic mudflows is a

composite volcano

What kind of metamorphism is occurring in this setting as indicated?

contact

What is the typical setting for fold and thrust belts?

convergent plate boundaries

The igneous feature shown in this figure is a

dike

An igneous rock that solidifies on Earth's surface is a(n)

extrusive rock

What types of rocks would be most common in the volcano in this photograph?

felsic and intermediate lava flows and tephra

The deep-sea floor is characterized by sediment dominated by

fine dust and the remains of single-celled organisms.

Shield volcanoes commonly involve

fluid lava flows

When basaltic lavas reach the ocean they

form pillow basalts

Which of these attributes preserved in sedimentary rocks gives us the most information about past climates?

fossils

Under what conditions was this rock likely deformed?

hot and deep conditions

The geothermal gradient is the

increase of the Earth's temperature with increase in depth

How does the addition of water cause melting?

it changes the location of the liquid-solid boundary

A mantle plume rises because

it is solid but less dense than material around it

The igneous feature shown in this figure is a

laccolith

A sinkhole is most likely to form from dissolution in:

limestone

Long, thin lava flows are typically produced by

low-viscosity lavas

An igneous rock rich in olivine and pyroxene is classified as __________ in composition.

mafic

According to the fossil record, what events have coincided with the approximate times when flood basalts were erupting?

mass extinctions

What type of structure is shown in this figure?

monocline

The transition from the gray shale and limestone to the sandstone and breccia above represents a:

regression

The main cause of melting along subduction zones is the

release of water from the subducting plate

What type of fault is shown in this figure?

reverse fault

The main way water gets into a subduction zone is by

seawater introduced into oceanic crust at the mid-ocean ridge, prior to subduction

What is the plate-tectonic setting of Mount Rainier?

subduction beneath the Pacific Northwest

If a rock is subjected to differential stress, then it means that

the amount of stress is greater in some directions than in others

A lava solidifies into nonvesicular basalt instead of vesicular basalt because

the lava has a low gas content

Which of the rock layers in this figure was most likely deposited by sand dunes on land?

the lowest red sandstone

What does this texture indicate about the formation of this rock?

the magna had abundant dissolved gas

The higher the gas pressure builds in a magma

the more explosive an eruption it is likely to produce.

A porphyritic igneous texture indicates that

the rock cooled slowly and then quickly

A finely crystalline or glassy igneous texture indicates that

the rock was cooled quickly

A vesicular igneous texture indicates that

there was a lot of gas in the magma

Which way was the current (either wind or water) moving during deposition of this section of rocks?

toward the right

Which of the following units was most likely deposited in the deepest marine water?

unit 5

What type of basaltic feature is shown in this photograph?

vesicles

Changes in topography, water chemistry, and gas output all are used to help predict

volcanic eruptions

The relationship between weathering and erosion can best be characterized as

weathering loosens material before erosion carries it away, but erosion can also scour and move unweathered material.

Which of the following attributes does NOT apply to these sediments?

well sorted

Columnar joints, such as the ones shown in the photograph, are formed

when hot but solid igneous rock contracts