Physical Geology - Chapter 6

Front 1

Igneous rocks

Back 1

Rocks that form from the solidification of a melt

Front 2

Melt

Back 2

hot liquid rock

Front 3

Lava

Back 3

Melt at the surface

Front 4

Magma

Back 4

Melt beneath the surface

Front 5

Igneous make up the great majority of the _______ , of the Earth and virtually all of the mantle ________ .

Back 5

crust, mantle

Front 6

The crust and mantle are ________ .

Back 6

rocky

Front 7

The core is _________ .

Back 7

metallic

Front 8

Intrusive rock

Back 8

The melt solidifies beneath Earth's surface (from magma)

Front 9

Intrusive rock is also known as _________ _________ .

Back 9

plutonic rock

Front 10

Intrusions

Back 10

bodies of intrusive rock

Front 11

Extrusive rock

Back 11

The melt solidifies at the Earth's surface from lava

Front 12

Geothermal gradient

Back 12

temperature increases with depth

Front 13

Where does the Earth's heat come from?

Back 13

- tidal friction due to the moon
- radioactive decay of isotopes
- accretion of planet and core formation

Front 14

tidal effect ---> frictional "________"

Back 14

braking

Front 15

Why is most of the mantle solid rock, despite temperatures of 1200 degrees C ?

Back 15

the temperature and pressure increase with depth, and the pressure generally tends to win

Front 16

Special circumstances that produce melting

Back 16

- addition of volatiles
- decompression
- addition of heat

Front 17

Decompression happens when ______ ______ ______ ______ ______ ________ ______ .

Back 17

hot solid rock rises in the mantle

Front 18

Decompression occurs at ______-_______ _______ and ______ ______ at the ________ .

Back 18

mid-ocean ridges, hot spots, aesthenosphere

Front 19

Hot spot

Back 19

A place where lots of hot mantle rock is rising

Front 20

Volatiles

Back 20

Substances that tend to lead to explosions

Front 21

The addition of volatiles occurs at _________ __________ .

Back 21

subduction zones

Front 22

An example of volatiles being added at a subduction zone is the _______ ______ ______ .

Back 22

Ring of Fire

Front 23

Addition of heat is caused by _________ with _______ _______ or _______ .

Back 23

contact, hot rock, magma

Front 24

The addition of heat occurs at _________ _______ _______ _______ _______ and _______ ________ .

Back 24

boundaries of large hot magma, subduction zones

Front 25

Grain size indicates _________ _________ .

Back 25

cooling rate

Front 26

Melts are ___________ liquids.

Back 26

amorphous

Front 27

Glassy

Back 27

- extrusive rocks only
- no crystals
- fast cooling

Front 28

Viscosity

Back 28

resistance to flowing

Front 29

The top of pillow basalts at mid-ocean ridges have _______ texture.

Back 29

glassy

Front 30

Melts with a low temperature are _________ viscous.

Back 30

highly

Front 31

Peanut butter and molasses have ________ viscosity.

Back 31

high

Front 32

Why does fast cooling lead to the absence of crystals?

Back 32

It ensures that the atoms cannot organize into crystals.

Front 33

Fast cooling (months)

Back 33

- aphanitic
- not glassy luster
- eg: Basalt

Front 34

Slow cooling (thousands to few million years)

Back 34

- phaneritic
-course or medium grained
- eg: Granite

Front 35

Very slow cooling (many millions of years)

Back 35

- pegmatic texture

Front 36

How are pegmatites formed?

Back 36

Circulation of hot water in fractures within rock

Front 37

Types of intrustions

Back 37

- plutons
- dikes
- sills

Front 38

Plutons

Back 38

Large, blob-shaped intrusions

Front 39

Plutons are formed when ________ ________ solidifies.

Back 39

magma body

Front 40

Dikes

Back 40

tabular intrusions that cut across bedded rocks

Front 41

Sills

Back 41

tabular intrusions that form parallel to bedded rocks

Front 42

How are dikes and sills formed?

Back 42

Solidification of intrusions in cracks

Front 43

Due to its slower cooling rate and deeper depth, ________ have the biggest grain size out of plutons, dikes, and sills.

Back 43

plutons

Front 44

Intrusions may find weaknesses in layers of _________ rock.

Back 44

sedimentary

Front 45

Condensation of water vapor from volcanic eruptions ------> _________

Back 45

oceans

Front 46

All atmospheric gasses except O_2 are derived from _________ __________ .

Back 46

volcanic outgassings

Front 47

Mafic: ________ + _________

Back 47

magnesium, iron

Front 48

Felsic: ________ + _________

Back 48

feldspar, silica

Front 49

Most rocks of the oceanic crust are __________ .

Back 49

mafic

Front 50

Most rocks of the continental crust are __________, sometimes ________ .

Back 50

felsic, intermediate

Front 51

Example of ultramafic rock with coarse-grained texture

Back 51

Peridotite

Front 52

Example of felsic rock with fine-grained texture

Back 52

Rhyolite

Front 53

Example of felsic rock with coarse-grained texture

Back 53

Granite

Front 54

Example of mafic rock with fine-grained texture

Back 54

Basalt

Front 55

Example of mafic rock with coarse-grained texture

Back 55

Gabbro

Front 56

Example of intermediate rock with fine-grained texture

Back 56

Andesite

Front 57

Example of intermediate rock with coarse-grained texture

Back 57

Diorite

Front 58

Bowen's Reaction Series:
1) ___________________
2) ___________________

Back 58

Continuous series, Discontinuous series

Front 59

Discontinuous series

Back 59

mafic rocks -------> felsic rocks

Front 60

Continuous series

Back 60

pure Ca plagioclase feldspar -------> pure Na plagioclase feldspar

Front 61

Magmatic evolution occurs due to one or more of three processes:
1) ___________________
2) ___________________
3) ___________________

Back 61

- fractional crystallization
- assimilation of surrounding (host) rock
- magma mixing

Front 62

Poryphyritic texture indicates that the rock has ________ cooling histories:
First - _______________ _________ _____________
Second - ______________ _________ _____________

Back 62

two, slow in Earth, fast on Earth

Front 63

Andesite has a _______ _______ color.

Back 63

medium grey

Front 64

Phenocrysts form ________ at ________ _________ .

Back 64

first, high temperatures