TEST #2 Flashcards

1
Q

This metamorphic rock is composed of alternating bands of light and dark silicate minerals.

A

Gneiss

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2
Q

A Metamorphic Facies is typically defined based on:

A

Two or more metamorphic minerals that occur together over a range of pressures and temperatures

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3
Q

Which of the following is the parent rock of quartzite?

A

Sandstone

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4
Q

Minerals that are good indictors of metamorphic environments are called:

A

Index minerals

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5
Q

Which low-grade metamorphic rock displays thin, parallel layers and contains very fine grains of mica?

A

Slate

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6
Q

______ is the process by which a rock changes form or mineral content as a result of environmental changes such as heat and pressure.

A

Metamorphism

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7
Q

Contact metamorphism is caused by ____, whereas regional metamorphism involves _______.

A

The heat of a nearby intrusion; both heat and stress

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8
Q

_____ is a widespread type of metamorphism typically associated with mountain building.

A

Regional metamorphism

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9
Q

Which of the following lists is in correct order going from lower to higher grade metamorphism?

A

Slate, phyllite, mica, schist

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10
Q

What is the definition of a parent rock (also known as a protolith)?

A

The rock that was altered by metamorphism

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11
Q

Which of the following is an essential characteristic of an index fossil?

A

The organism only lived for a short period of geologic time

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12
Q

Which scientist is credited with developing the law of superposition?

A

Nicholas Steno

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13
Q

The first 3 periods of the Paleozoic era are (in order from oldest to youngest) are:

A

Cambrian, Ordovician, and Silurian

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14
Q

What is the nature of the unconformity between sediments J and N as shown in the diagram?

A

Disconformity

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15
Q

About 85% of geologic time is represented by the time span called the:

A

Precambrian

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16
Q

A layer of sandstone is in contact with a mass of granite. The granite contains small pieces of the sandstone. What rock is older?

A

Sandstone

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17
Q

Radiometric dating is least useful for dating _____ rocks.

A

Sedimentary

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18
Q

You are trying to determine the age of a lava flow using an isotope with a half-life of 1.5 million years. If the sample has gone through four half-lives, what is the age of the rock?

A

6 million years

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19
Q

A neutron is a combination of a(n) ____ and a(n) _____.

A

electron, proton

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20
Q

The half-life of carbon-14 about 6000 years. Assume that a sample of charcoal formed by burning of living wood 15000 years ago. How much of the original carbon-14 would remain today?

A

Between one-fourth and one-eighth

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21
Q

How does tensional force charge a rock body?

A

Stretch and thin the rock

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22
Q

Faults form in _____ temperature- _____ pressure environments.

A

low; low

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23
Q

Which tectonic boundary is associated with compressional stress?

A

Convergent

24
Q

Linear upfolded structures with the oldest strata in the center are termed:

A

Anticlines

25
Q

Faults having primarily horizontal movement are called:

A

Strike-slip faults

26
Q

Tensional forces normally cause which of the following?

A

Normal faults

27
Q

A low angle reverse fault is termed:

A

Thrust fault

28
Q

Anticlines and synclines are generally:

A

Products of compressional stress

29
Q

Which of the following combinations should favor folding rather than faulting?

A

High temperature and high confining pressure

30
Q

What is the outcrop pattern of a plunging syncline?

A

The layers will open up in the direction of plunge

31
Q

Which of the following is used to describe what occurs to produce an earthquake?

A

Elastic rebound

32
Q

A point on the Earth’s surface which lies vertically above the point of origin of an earthquake is termed the

A

Epicenter

33
Q

Earthquake A is classified as a 3 on the Richter scale. Earthquake B is classified as a 6. Approximately how many times energy has Earthquake B released than Earthquake A?

A

33000 times

34
Q

Primary waves are typically best seen (most easily recorded) on which of the following seismograph records:

A

Vertical

35
Q

The type of seismic wave propagates through intervening material by compressing and dilating the rocks in the direction the wave is traveling.

A

P waves

36
Q

The type of seismic waves travels the most rapidly.

A

P waves

37
Q

The asthenosphere is a part of the:

A

Mantle

38
Q

The dense core of the earth is thought to consist predominantly of:

A

Iron

39
Q

What will happen to a seismic wave when it is refracted?

A

The wave will be bent when passing into a material of differing density

40
Q

Which one of the following is the thinnest layer of the earth?

A

Crust

41
Q

Wegner dubbed the Permian supercontinent:

A

Pangea

42
Q

Mountains formed by the collision between continents are the:

A

Himalayas

43
Q

The African Rift valleys are associated with a:

A

Divergent boundary

44
Q

In the plate tectonics model, the earth’s outer shell consists of about _______ individual plates.

A

20

45
Q

Which of the following is associated with an active continental margin?

A

Convergent boundaries

46
Q

Charles Darwin was first time explain how reef-building organism which require shallow, sunlight water could create reef complexes that extend for thousands of meters below sea level. Darwin hypothesized that:

A

As volcanic islands with fringing coral reefs began to sink, these organisms kept pace by building the reef complex upward

47
Q

What rock would you expect to find associated with a mid-ocean ridge?

A

Basalt

48
Q

Island arcs are associated with:

A

Convergent (oceanic-oceanic) boundaries

49
Q

The collision of North America and Europe/Asia during the Paleozoic era resulting in the formation of the

A

Appalachians

50
Q

A sample of basalt in which the magnetic field is oriented horizontally probably cooled:

A

Near the equator

51
Q

What tool is often used to measure the topography of the sea floor today?

A

Sonar

52
Q

The formation of the Hawaiian Islands is associated with:

A

No plate boundary of any kind

53
Q

If the earth’s magnetic field did not occasionally reverse polarity:

A

The sea floor would not contain (produce) magnetic stripes.

54
Q

The Andes mountains were generated at a:

A

Convergent (oceanic-continental) boundary

55
Q

What are the two types of continental margins?

A

Passive and active