Rocks

Question 1

What are igneous rocks?

Answer 1

Form as molten rock cools and solidifies

Question 2

What is magma?

Answer 2

Intrusive rocks or plutonic rocks

Question 3

What is lava?

Answer 3

Extrusive rocks or volcanic rocks

Question 4

What are extrusive igneous rocks?

Answer 4

Magma that exists or cooled above ground

Question 5

What are intrusive igneous rocks?

Answer 5

Magma that cooled below ground surface

Question 6

What are the three components of magma?

Answer 6

1. Liquid portion = melt
2. Solids, if present, silicate materials
3. Volatiles = dissolved gases in melt

Question 7

What determines the texture of igneous rocks?

Answer 7

Rate of cooling
1. Slow rate = fewer but larger crystals
2. Fast rate = many small crystals
3. Very fast rate = forms glass

Question 8

What are the different igneous textures?

Answer 8

Aphanitic
Porphyritic
Phaneritic
Glassy
Pyroclastic
Pegmatitic

Question 9

What is an aphanitic texture?

Answer 9

Fine-grained
Rapid rate of cooling
Microscopic crystals

Question 10

What is a phaneritic texture?

Answer 10

Coarse-grained
Slow cooling
Large, visible crystals

Question 11

What is a porphyritic texture?

Answer 11

2 stages of cooling
Large crystals embedded in smaller crystals

Question 12

What is a glassy texture?

Answer 12

Very rapid cooling
Results in obsidian

Question 13

What is a pyroclastic texture?

Answer 13

Fragmental appearance
Formed by violent volcanic eruptions

Question 14

What is a pegmatitic texture?

Answer 14

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

Question 15

What are the different igneous compositions?

Answer 15

Felsic
Intermediate
Mafic
Ultramafic

Question 16

What determines igneous composition?

Answer 16

Silica content

Question 17

What is a felsic composition?

Answer 17

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

Question 18

What is an intermediate composition?

Answer 18

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

Question 19

What is a mafic composition?

Answer 19

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

Question 20

What is an ultramafic composition?

Answer 20

Rare
Entirely ferromagnesian silicates
< 45% silica

Question 21

How does magma originate?

Answer 21

Heat
Pressure
Volatiles

Question 22

How do sedimentary rocks form?

Answer 22

products of mechanical & chemical weathering

Question 23

What are the types of sedimentary rocks?

Answer 23

Detrital rocks
Chemical rocks

Question 24

What are detrital rocks?

Answer 24

Transported sediment as solid particles

Question 25

What are chemical rocks?

Answer 25

Sediment once in solution

Question 26

What are types of detrital rocks?

Answer 26

Shale Sandstone Conglomerate & breccia

Question 27

What are types of chemical rocks?

Answer 27

Limestone Dolostone Chert Evaporites Coal

Question 28

What are the classifications of chemical rocks?

Answer 28

Clastic Nonclastic

Question 29

What is a clastic rock?

Answer 29

Discrete fragments & particles

Question 30

What is a nonclastic rock?

Answer 30

Pattern of interlocking crystals (resemble igneous rocks)

Question 31

What are the types of sedimentary structures?

Answer 31

Bedding planes Cross-bedding Graded beds Ripple marks Mud cracks

Question 32

What is metamorphism?

Answer 32

Transition of one rock into another by temperatures and/or pressures

Question 33

What are the types of metamorphism?

Answer 33

Contact metamorphism (heat) Dynamic metamorphism (pressure) Regional metamorphism (heat and pressure)

Question 34

What are the agents of metamorphism?

Answer 34

Heat Pressure & stress Fluids Parent rock

Question 35

What are the two types of pressure?

Answer 35

Lithostatic Differential

Question 36

What is lithostatic pressure?

Answer 36

Weight of the overlying rocks

Question 37

What is differential pressure?

Answer 37

Pressures that are not equal on all sides

Question 38

What are the metamorphic textures?

Answer 38

Foliated Non-foliated

Question 39

What is texture?

Answer 39

Size, shape, & arrangement of mineral grains

Question 40

What is foliation?

Answer 40

Planar arrangement of mineral grains

Question 41

What are the types of foliated textures?

Answer 41

Slaty cleavage Schistosity Gneissic

Question 42

What are types of foliated rocks?

Answer 42

Slate Phyllite Schist Gneiss

Question 43

What are the types of non-foliated rocks?

Answer 43

Marble Quartzite

Question 44

What are the different metamorphic environments?

Answer 44

Continental Transformational Marine