Deck 20: Interlude A: Rock Groups

Question 1

What type of texture is shown in the photomicrograph?

A)foliation
B)crystalline
C)sedimentary
D)clastic

Answer 1

B

Question 2

Imagine you are holding a rock composed of small sand grains cemented together.What subclassification of sedimentary rock is this?

A)clastic
B)chemical
C)igneous
D)crystalline

Answer 2

A

Question 3

A(n)________ of minerals forms a rock.

A)compilation
B)aggregate
C)mass
D)assembly

Answer 3

B

Question 4

Where would you expect to find metamorphic rocks forming?

A)deep inside a mountain range
B)inside a lava flow on Hawaii
C)under the water at the mid-ocean ridge
D)at the bottom of the Mediterranean Sea

Question 5

Which type of rock is formed by precipitation of minerals from a solution?

A)metamorphic
B)glassy
C)sedimentary
D)igneous

Question 6

A pile of unconsolidated sediment is NOT ________ and therefore NOT a rock.

A)coherent
B)aggregated
C)natural
D)solid

Question 7

A piece of concrete from a driveway is NOT considered a rock because it ________.

A)is made of one mineral
B)does not contain minerals
C)is unconsolidated
D)is man-made

Question 8

A(n)________ takes extremely high resolution images that can be used to determine the elements in a rock.

A)petrographic microscope
B)scanning electron microscope
C)X-ray diffractometer
D)photomicrograph

Question 9

Rocks are ________ and thus not man-made.

A)coherent
B)synthetic
C)rare
D)natural

Question 10

Why do geologists classify rocks?

A)to determine the chemical makeup of Earth
B)because rocks are the key to determining the Earth's history
C)because it makes it easier to tell them apart
D)so that they can tell how old the rock is

Question 11

Geologists sometimes use analytical equipment to help identify rocks.One commonly used machine is the electron microprobe,which focuses a beam of electrons on a sample to determine ________.

A)the amount of radioactive minerals
B)how atoms are arranged
C)the atomic weight
D)the chemical composition

Question 12

Igneous rocks form from ________.

A)heat and pressure applied to a rock
B)precipitation of minerals out of a solution
C)sediments cemented together
D)molten rock cooling and forming crystals

Question 13

A(n)________ material is held together,solid,and must be broken apart to separate it into smaller pieces.

A)unconsolidated
B)paved
C)coherent
D)buttressed

Question 14

The picture below shows a(n)________ of rock that geologists use to determine the minerals in the rock.

A)hand sample
B)thin section
C)outcrop
D)X-ray

Question 15

Which of the following describes a rock?

A)a pile of damp sand still holding the form of a bucket
B)a collection of crystals that fit together like puzzle pieces
C)cobblestones cemented together to form a walkway
D)a layer of mud at the bottom of a dry river bed

Question 16

What is the difference between a rock that is cemented and a rock that is crystalline?

A)A rock that is cemented contains rounded grains that are held together by cement,whereas a crystalline rock contains angular grains held together by cement.
B)Crystalline rocks contain minerals,while cemented rocks contain rock fragments;both are held together by static forces between grains.
C)Minerals are held together as interlocking pieces in a cemented rock,whereas grains are held together by minerals precipitated in pore spaces in a crystalline rock.
D)Minerals are held together as interlocking pieces in a crystalline rock,whereas in a cemented rock the grains do not fit together like puzzle pieces and instead are held together by cement.

Question 17

Looking at a ________ helps geologists identify minerals and classify rocks.

A)thin section
B)micro section
C)thin slide
D)micro slide

Question 18

Which one of the pictures does NOT show (a)rock(s)?

A)Figure A
B)Figure B
C)Figure C
D)Figure D

Question 19

Composition describes the ________.

A)degree of compaction and cementation in a rock
B)arrangement of minerals in a rock
C)presence of layers of minerals in a rock
D)chemical makeup of a rock

Question 20

Which is a characteristic used to classify a rock?

A)mineral stability
B)rock texture
C)water content
D)degree of weathering

Question 21

Give the definition of rock texture.

Question 22

Which of the following images shows a hand specimen?

A)A
B)B
C)C
D)D

Question 23

List the three main rock groups and give a brief description of how each is formed.

Question 24

Which of the images below shows a rock? Explain your reasoning.

Question 25

Why do thin sections help geologists identify minerals better than with a hand specimen alone?

A)Thin sections allow the geologist to identify the chemicals within the minerals.
B)Each mineral transmits polarized light differently and displays variations in colors.
C)Looking at a thin section allows the geologist to see the atomic structure of the minerals.
D)Cutting a thin section removes the weathered surface and shows the minerals' true colors.

Question 26

Is a piece of concrete a rock? Why or why not?

Question 27

Why do geologists use thin sections of rocks?

A)to determine if the rock is molten
B)to identify foreign substances
C)to identify the minerals
D)to determine the arrangement of atoms

Question 28

Which piece of equipment is used to help a geologist see the internal structure of minerals?

A)electron microprobe
B)mass spectrometer
C)X-ray diffractometer
D)petrographic microscope

Question 29

How is a thin section made,and what is it used for?

Question 30

Which of the following tools is used to identify minerals in the field?

A)thin section
B)hand lens
C)petrographic microscope
D)photomicrograph