geology 101 exam 2

Which location on this diagram would most likely record contact metamorphism in shallow levels of the crust?

1

Which location on this diagram would result from burial to moderate depths accompanied by normal heating of rocks (regional metamorphism)?

2

An mineral contains 900 parent atoms and 300 daughter atoms. If the half-life for the radioactive element is 40 million years, how old is the rock?

20 million years

Using the data in this table, calculate the number of half-lives that have passed for the granite (unit G on this table)?

3

A rock contains 7000 daughter atoms and 1000 radioactive parent atoms. If the half-life for the radioactive reaction is 10 million years, how old is the rock?

30 million years old

Which of these conditions could form rocks that are partly metamorphic and partly igneous?

4

An igneous rock formed with 144 radioactive (parent) atoms, but contains only 36 radioactive (parent) atoms today. If the half life for the radioactive element is 20 million years, how old is the rock?

40 mil

Which of the following is most likely to occur at shallow crustal levels?

Brittle deformation

Name the volcanic landforms (small red hills) from the following picture.

Cinder cone

What type of stress creates thrust faults?

Compressional

Name the type of fault from the diagram below.

Left lateral strike-slip fault

What is a normal fault?

Normal faults are usually associated with tensional stress

What type of stress results in strike-slip faulting?

Shear

This figure shows two sections that represent the same age range and contain some of the same fossils. If you compare the two sections, what conclusions do you come to?

Some units were deposited in the left section but not in the right one or were eroded away.

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 was narrower?

The force would remain the same, but the amount of stress would increase.

Which of the following is NOT true about shield volcanoes in the landscape?

They are large mountains with steep slopes.

Which of the following is NOT true of calderas?

They are produced by removal of easily eroded pyroclastic materials.

Which of the following rock types is NOT characteristic of volcanic domes?

Vesicular basalt with very large holes from dangerous gas.

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

Viscous magma prevents gas from escaping easily.

This picture of volcanic breccia would be most likely formed in which type of volcano?

Volcanic Dome

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

a and b

Which of the following is common in most calderas?

a large, circular depression with steep walls

Which of the following describes a thrust fault?

a low-angle, reverse fault

Which of the following factors indicates a high risk for volcanic mudflows or lahars?

a volcano with a thick covering of snow or ice

Flood basalts influence life on Earth because:

all of these

Shield volcanoes commonly have:

all of these

This photograph shows an upper unit with fragments and a lower unit with tilted layers. Which of the following statements is true?

all of these

Which of the following does NOT help define foliation in metamorphic rocks?

all of these

Which of the following does NOT match a sedimentary rock with a possible metamorphic equivalent?

all of these are correct matches

Which of the following are forms of differential stress?

all of these are forms of differential stress

Which of the following rocks cannot be metamorphosed?

all of these can be metamorphosed

The foliation in a schist is usually

an orientation of mica

Intermediate and felsic magmas usually form:

at subduction zones.

Which letter corresponds to high pressure but low temperature metamorphism?

b

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

basalt

Examine the geologic cross section above. Which feature is the youngest?

basalt dike

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

c

What letter(s) corresponds to areas high temperature but low pressure metamorphism?

c

Which of the following isotopes of carbon is radioactive?

c-14

Foliated metamorphic rocks are always

caused by a directed pressure

All of the following volcanic products are produced by felsic eruptions except:

cinder cones

The main cause of caldera collapse is:

collapse of the roof of a magma chamber as magma erupts

A common volcanic feature that forms in basaltic lava flows when they cool and contract is:

columnar joints

The most dangerous type of volcano is a:

composite volcano

This relatively large, symmetrical volcano contains interlayered lava flow, pyroclastic deposits, and volcanic mudflows. What kind of volcano is it?

composite volcano

Which of the following is an example of a caldera that we talked about in class?

crater lake

In what site on this figure would you expect regional metamorphism?

d and e

What letter(s) corresponds to areas undergoing regional metamorphism?

d and e

Which of the following features is younger than fault 2?

deposits along the fault

The Columbia River Plateau was formed from:

flood basalts

This rock is called a volcanic tuff. It would most likely be formed in which of the following types of eruptions

from a large pyroclastic eruption

Which of the following rocks represents the highest metamorphic grade?

gneiss

Which of the following lists is arranged in order from highest to lowest grade of metamorphic rock?

gneiss, schist, phyllite, slate

In this diagram, the contact between the granite (unit 1) and the lowest layer (unit 2) is depositional and the dike (unit 6) cuts across both units. What is the oldest unit?

granite (unit 1)

Unit C is present in the left column but not the right column because:

it was not deposited or was eroded away

Which of the following features is younger than fault 1?

lava flow and granite

Marble is a metamorphic rock that forms from a ___________ parent .

limestone

Which of these is not a common gas in magma?

methane

Which mineral is responsible for the strong foliation in a schist?

mica

Isotopes of an element have the same number of _________ but a different number of __________.

protons, neutrons

Which of the following metamorphic rocks can not form from a shale?

quartzite

Place the following lava flows in order of decreasing (high to low) lava viscosity.

rhyolite-andesite-basalt

Quartzite is a metamorphic rock that forms from a __________ parent.

sandstone

Examine the geologic cross section above. Which of the following features is the oldest?

sandstone(5)

This volcano is relatively small and composed of volcanic cinders. What kind of volcano is it?

scoria cone

What type of volcanoes would you expect to find in Hawaii?

shield volcanos

Which of the following rocks represents the lowest metamorphic grade?

slate

Volcanic domes commonly are partially destroyed when:

steep parts of the dome collapse and cause small pyroclastic flows

Which of the following types of faults has only horizontal or lateral motion?

strike-slip

Which of the following tectonic settings is the most likely to produce composite volcanoes?

subduction zone

Which type of stress would most likely form the fault in the diagram below?

tension

Which type of stress creates normal faults?

tensional

In regional metamorphism the source of increased temperature and pressure is _________ .

the increase in temperature with increasing depth of burial and compression

In this diagram the contact between the granite (unit 1) and the lowest layer (unit 2) is depositional. What is the youngest unit?

the lava flow (unit 11)

Which of the following true of intermediate composition lavas?

they form composite cones

Which of the following is not true of felsic lavas?

they form shield volcanoes

Which is the oldest feature in the diagram?

tilted layers

Tracks and burrows are examples of ________ fossils.

trace

What type of feature is shown in this photograph of Siccar Point, Scotland?

unconformity

Magma with a high silica content tends to be:

very viscous

Which of the following best describes an anticline?

All of the above

Which of the following statements best describes a syncline?

All of the above are true

Which of the following is a valid statement about how rocks respond to stress?

If a rock has strained, then it has changed its size or shape.