Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GEO 101 Exam 2 & 3 > Igneous Rocks > Flashcards

Igneous Rocks Flashcards

1
Q

What are igneous rocks?

A

Form as molten rock cools and solidifies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is magma?

A

Intrusive rocks or plutonic rocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is lava?

A

Extrusive rocks or volcanic rocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are extrusive igneous rocks?

A

Magma that exists or cooled above ground

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are intrusive igneous rocks?

A

Magma that cooled below ground surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three components of magma?

A
  1. Liquid portion = melt
  2. Solids , if present, silicate materials
  3. Volatiles = dissolved gases in melt, e.g. water vapor, carbon dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What determines the texture of igneous rocks?

A

Determined by rate of cooling
1. Slow rate = fewer but larger crystals
2. Fast rate = many small crystals
3. Very fast rate = forms glass (aphanitic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the different igneous textures?

A

Aphanitic
Porphyritic
Phaneritic
Glassy
Pyroclastic
Pegmatitic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an aphanitic texture?

A

Fine-grained
Rapid rate of cooling
Microscopic crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a phaneritic texture?

A

Coarse-grained
Slow cooling
Large, visible crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a porphyritic texture?

A

2 stages of cooling
Large crystals embedded in smaller crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a glassy texture?

A

Very rapid cooling
Results in obsidian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a pyroclastic texture?

A

Fragmental appearance
Formed by violent volcanic eruptions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a pegmatitic texture?

A

Exceptionally coarse-grained
Forms in late stages of crystallization of magmas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the different igneous compositions?

A

Felsic
Intermediate
Mafic
Ultramafic
Silica content indicates composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a felsic composition?

A

Silica rich & iron poor
Nonferromagnesian silicates
Silica rich
Major constituent of continental crust

16
Q

What is an intermediate composition?

A

More iron & less silicate
>25% ferromagnesian minerals
53-65% silica

17
Q

What is a mafic composition?

A

More iron & magnesium
Ferromagnesian silicates
Silica poor (45-52%)
Comprise ocean floor & volcanic islands

18
Q

What is an ultramafic composition?

A

Rare
Entirely ferromagnesian silicates
<45% silica

19
Q

How does magma originate?

A

Heat
Pressure
Volatiles

20
Q

What is Bowen’s reaction series?

A

Minerals crystallize in a systemic fashion based on melting points
During crystallization, composition of liquid portion of magma continually changes

GEO 101 Exam 2 & 3 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions