Igneous Rock Classification

Question 1

Three main igneous textures

Answer 1

crystalline
fragmental
glassy

Question 2

define aphanitic

Answer 2

fine grained crystals grow quickly under conditions of rapid cooling, typically in extrusive settings

1 stage of cooling

Question 3

define phaneritic

Answer 3

coarse grained crystals grow larger by cooling slowly typically intrusive

1 stage of cooling

Question 4

defined porphyritic

Answer 4

both small and large crystals (called phenocrysts)

initial slow cooling followed by rapid cooling (usually after eruption)

2 stages of cooling

Question 5

texture of rhyolite andesite and basalt

Answer 5

aphanitic

Question 6

texture of granite diorite and gabbro

Answer 6

phaneritic

Question 7

mafic melts have a high proportion of

Answer 7

magnesium and iron relative to silica

Question 8

mafic rocks are usually ___ colored

Answer 8

dark

Question 9

mafic rocks have ____ specific gravity than felsic

Answer 9

higher

Question 10

Basalt and diorite M/F

Question 11

Felsic color

Answer 11

lighter

Question 12

felsic specific gravity

Answer 12

lower than mafic

Question 13

rhyolit and granite M/F

Answer 13

felsic

Question 14

Grain size has to do with

Answer 14

history not composition

Question 15

peridotite M/F A/P I/S/M

Answer 15

ultramafic phaneritic igneous

Question 16

andesite M/F A/P I/S/M

Answer 16

intermediate anphanitic igneous

Question 17

komatite / picrite M/F A/P I/S/M

Answer 17

ultramafic anphanitic igneous

Question 18

granite M/F A/P I/S/M

Answer 18

felsic phaneritic igneous

Question 19

freezing temp is proportional to __ density __ silica content ____how mafic it is

Answer 19

+ - +

Question 20

what is pumice

Answer 20

felsic rock full of vesicles
it floats

glassy igneous rock

Question 21

what is scoria

Answer 21

vesicular and glassy mafic rock

glassy igneous

Question 22

what is obsidian

Answer 22

glassy felsic rock, no vesicles

glassy igneous

Question 23

what the 3 main glassy igneous rocks

Answer 23

pumice
scoria
obsidian

Question 24

what are the pyroclastic igneous rocks

Answer 24

tuff: fused volcanic ash
volcanic breccia : angular fragments that have fused together

Question 25

a volcano is

Answer 25

a mountain constructed by the eruption of molten rock from earths interior

Question 26

volcanoes are a direct consequence of

Answer 26

plate tectonics and mantle convections

Question 27

Products of volcanic eruptions

Answer 27

lava flows volcanic gases pyroclastic debris

Question 28

lava flows are

Answer 28

molten rock that moves over the ground

Question 29

volcanic gases are

Answer 29

expelled vapor’s and aerosols

Question 30

pyroclastic debris are

Answer 30

fragments blown out of a volcano

Question 31

in violent eruptions

Answer 31

gas escape is difficult

Question 32

in mellow eruptions

Answer 32

gas escape is easy

Question 33

mellow eruptions have _ viscosity

Answer 33

low

Question 34

violent eruptions have _ viscotisy

Answer 34

high

Question 35

basaltic lava has

Answer 35

low viscosity and can travel long distances

Question 36

andesitic lava is

Answer 36

too viscous to flow far and tends to break up as it flows

Question 37

felsic lava is

Answer 37

so viscous that it may pile up in a dome shaped mass

Question 38

basaltic lava flows are

Answer 38

very hot, mafic, low viscosity

Question 39

basalt flows are often

Answer 39

thin and fluid go long distances

Question 40

Lava tubes are

Answer 40

conduits for basaltic lava

Question 41

andesitic lava flows have

Answer 41

higher silica , a bit viscous, mound the vent and slow f lowly, cooled crust cracks into rubble

Question 42

rhyolitic lava flows

Answer 42

high silica (felsic), more viscous, don’t really flow at all, can be blown out during an eruption

Question 43

rhyolitic eruptions look like

Answer 43

big smoke clouds

Question 44

pyroclastic flows are

Answer 44

flow of hot molten pyroclastic debris, 500-1000C ash that travels at up to 300 Km/h

Question 45

Tuff is

Answer 45

lithified ash

Question 46

an air fall tuff accumulates like

Answer 46

snow

Question 47

an ignimbrite is a

Answer 47

tuff that is deposited while still hot; it welds together

Question 48

pyroclastic debris can trap

Answer 48

volcanic gas

Question 49

pyroclastic debris has ____ specific gravity

Answer 49

low

Question 50

3 types of volcanoes

Answer 50

shield volcanoes cinder cones stratovolcanoes

Question 51

magma chambers are located

Answer 51

in the upper crust

Question 52

fissures happen when

Answer 52

magma erupts along a linear tear or through a pipe shaped conduit with a crater at the top

Question 53

a crater is

Answer 53

a bowl shaped depression atop a volcano

Question 54

a caldera is

Answer 54

a gigantic volcanic depression, they quickly fill with water and become a lake

Question 55

calderas are _____ than craters

Answer 55

much larger

Question 56

shield volcanoes are shaped like

Answer 56

a dome

Question 57

shield volcanoes have what kind of lava

Answer 57

low viscosity basaltic

Question 58

shield volcanoes have ___ violent eruptions

Answer 58

not very

Question 59

what kind of volcano is hawaii

Answer 59

shield volcano

Question 60

cinder cones are what shape

Answer 60

a cone dumbfuck no shit

Question 61

cinder cones are the smallest type of

Answer 61

volcano

Question 62

cinder cones form from

Answer 62

ejected fragments that have built up at the angle of repose around the vent

Question 63

stratovolcanoes are also known as

Answer 63

composite volcanoes

Question 64

stravolcano shape

Answer 64

large cone shape, steep slopes

Question 65

stratovolcanoes are made of

Answer 65

alternating layers of felsic lava tephra and debris

Question 66

mt st helen’s, mt fuji, mt vesuvius and mt pinotubo are all what kind of volcano

Answer 66

stratovolcano

Question 67

stratovolcanoes have a ____ violent eruption

Answer 67

VERY

Question 68

rank the following in size, caldera, cinder volcanoes, shield volcanoes, stratovolcano small to large

Answer 68

cinder strato caldera shield

Question 69

3 main Eruption styles

Answer 69

effusive explosive plinian

Question 70

effusive characteristics

Answer 70

outpouring of basaltic lava rivers of lava lava lakes can form near the vent lava fountains 500 m high

Question 71

explosive characteristics

Answer 71

high gas pressure more viscous siO2 rich mostly andesitic and rhyolitic

Question 72

Plinian characteristics

Answer 72

often destroy a part of the stratovolcano that created them create a convective cloud

Question 73

why are they called plinean

Answer 73

roman scholar pliny saw vesuvius erupt

Question 74

what is a lahar

Answer 74

volcanic ash and debris mixed with water which travel along drainage ways

Question 75

when do lahars occur

Answer 75

snow ice or rain eruption or not

Question 76

volcanoes cause landslides as

Answer 76

movement destabilizes flanks debris falls off the mountain

Question 77

volcanoes cause tsunamis by

Answer 77

destabilizing flanks or caldera collapse

Question 78

active volcanoes

Answer 78

are erupting, have erupted recently, are likely to erupt

Question 79

dormant volcanoes

Answer 79

haven’t erupted in hundreds to thousands of years

Question 80

extinct volcanoes

Answer 80

are no longer capable of erupting

Question 81

to predict eruptions

Answer 81

magma movement causes a change in shape that can be measured with tiltmeters or satellite radar

Question 82

to mitigate volcanic hazards

Answer 82

don’t build near them don’t build on lahar drainage routes

Question 83

pinatubo is what eruption type

Answer 83

plinian

Question 84

mount kilauea is what type of volcano

Answer 84

shield volcano

Question 85

mount kilauea has what eruption type

Answer 85

hawaiian (i know its stupid)

Question 86

Eyjafjallajokull has what type of eruption

Answer 86

strombolian (i know what the fuck)

Question 87

white island eruption type

Answer 87

phreatic

Question 88

vesuvius eruption type

Answer 88

plinian or vesuvian

Question 89

nyiragongo volcano type

Answer 89

stratovolcano

Question 90

hawaiian characteristics

Answer 90

predominately effusive, flows with minor scoria

Question 91

strombolian characteristics

Answer 91

periodically erupts a fountain of scoria lapilli and ash

Question 92

vulcanian characteristics

Answer 92

erupts both scoria tapili and tall plumes of pyroclastic debris

Question 93

phreatic characteristics

Answer 93

groundwater interacts with magma producing a steam explosion and blocks of wall rock

Question 94

phreatomagmatic characteristics

Answer 94

eruption involves steam explosion but also eruption of wet ash, lapilli, and blocks of lava

Question 95

surtseyan characteristics

Answer 95

seawater enters the magma chamber and does phreatomagmatic making steam explosions

Question 96

nyiraragongo is on lake

Answer 96

kivu

Question 97

nyirgongo is characterized by its

Answer 97

vents and fissures

Question 98

limnic eruptions are

Answer 98

eruptions of gases in a lake, slow release of poison

Question 99

lake nyos eruption type

Answer 99

limnic