Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Earth Science > Volcanoes > Flashcards

Volcanoes Flashcards

(57 cards)

Start Studying
1
Q

Molten rock beneath the Earth’s surface

A

Magma

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

Erupted magma

A

Lava

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q
  • igneous rocks contain a high percentage of dark silicate minerals and calcium-rich plagioclase feldspar (but no quartz) and tend to be dark in color
A

Basaltic

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

Contains mainly light-colored silicate minerals - quartz and potassium feldspar

A

Rhyolite

Intrusive equivalent: granite

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

Have a composition between basaltic and rhyolitic rocks

A

Andesitic rocks

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

Basaltic or

A

Mafic

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

Rhyolitic or

A

Felsic

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

Basaltic * magmas contain … SiO2

  • gas content
  • eruptive temperature
  • viscosity
A

Least ~ 50% SiO2
Least ~ 0.5-2.0% Gas
Highest Temperature (1000-1250 C)
Least viscous

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

Rhyolitic * magmas contain … SiO2

  • gas content
  • eruptive temperature
  • viscosity
A

Most ~ 70% SiO2
Most ~ 5-8%
Lowest Temperature (650-900 C)
Most Viscous

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

Basaltic (mafic)

A

High in Mg, Ca, Fe

Low in Na, K

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

Rhyolitic (felsic)

A

High in Na, K

Low in Mg, Ca, Fe

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

The magmas generated by melting mantle rocks tend to have * composition

/partial melting of solid rock/

A

Basaltic

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

In continental crust, the rising molten rock ponds at the crust-mantle boundary, melting the overlying crustal rock. This generates * magna of * composition

A

Less dense, more silica-rich magma

Andesitic or rhyolitic composition

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

Nonexplosive eruptions that produce outpourings of fluid lava

A

Quiescent or efusive

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

Opposite of effusive eruptions

A

Explosive eruptions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Two primary factors that determine how magma erupts:

A

Viscosity and gas content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What type of magma tends to generate quiescent (nonexplosive) eruptions?

A

Basaltic: fluid + low gas content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What type of magma tends to generate explosive eruptions?

A

Rhyolitic and andesitic

Silica-rich magmas, most viscous, greatest amount of gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Magma’s viscosity depends on

A

Temperature and silica content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Viscous

  • SiO2
  • C
A

More silica, more viscous

Lower temperature, more viscous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Most abundant gas found in most magma

A

Water vapor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Vast majority of Earth’s lava is

> 90%

A

Basaltic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Two types of lava

24
Q

Have surfaces of rough jagged blocks with dangerously sharp edges

25
Exhibit smooth surfaces that sometimes resemble twisted braids of ropes On which one can walk
Pahoehoe
26
Dissolved gases held in molten rock by confining pressure
Volatiled
27
Most abundant-least abundant gas released in the atmosphere
Water vapor (H2O), CO2, SO2 H2S, CO, H2
28
When volcanoes erupt, they eject pulverized rock and fragments of lava and glass called
Pyroclastic materials
29
Pyroclastic materials Etymology; also known as
Pyro = fire, clast = fragment Tephra
30
Produced when gas-rich viscous magma erupts explosively Less than 2mm (0.08 in)
Ash and dust particles
31
“Little stones” Small beads to walnuts (2-64 mm)
Lapilli or cinders
32
Larger than 64 mm or 2.5 in *hardened, incandescent
Blocks - hardened lava | Bombs - incandescent lava
33
Vesicular ejecta produced most often during eruption of basaltic magmas Reddish-brown fragments
Scoria
34
Usually light color and less dense emitted when magmas with an andesitic or rhyolitic compositions erupt explosively
Pumice
35
Volcanic activity frequently begins when a * develops in Earth’s crust as magma moves forcefully toward the surface
Fissure (crack)
36
Path of magma localized into somewhat pipe-shaped * that terminates at a surface opening called *
Conduit, vent
37
Coneshaped structure created by successive eruptions of lava, tephra
Volcanic cone
38
Located at the summit of most volcanic cones is a funnel-shaped depression
Crater
39
Very large circular depressions > 1 km, at most 50 km |<1 km|•
Calderas Collapse pits or craters
40
Vent that emits only gases
Fumaroles (fumus = smoke)
41
Produced by accumulation of fluid basaltic lavas Huge, gently sloping volcanoes built of very thin lava spreading out in all directions from a central vent Broad, slightly dome structure *oceanic
Shield volcanoes
42
Result from eruptions of moslty small pieces of scoria and pyroclastics *basaltic
Cinder cones/ scoria cones
43
Cone-shaped volcanoes composed of layers of lava, ash and rock debris
Composite cone volcanoes “stratovolcanoes”
44
Built by slow eruptions of highly viscous lava. Any steep-sided mound formed when lava reaching The Earth’s surface is so viscous that it cannot flow away readily and accumulated around the vent
Lava domes
45
A fluidized mixture of hot rock fragments, hot gases infused with incandescent ash and larger lava fragments Also called
Pyroclastic flows Nuee ardentes (glowing avalanches)
46
The greatest volume of volcanic material is extruded from * These voluminous accumulations are * because they tend to be rather flat and broad
Fissures Basalt plateaus
47
Volcanic object created when magma hardens within a vent on an active volcano
Volcanic plug, volcanic neck or lava neck
48
Body of intrusive igneous rock that is crystallized from magma slowly cooling below the surface of the Earth
Pluton
49
Intrusive igneous bodies are generally classified according to their shape as either * or * (large and blob shaped)
Tabular (tabula = table), massive
50
Orientation: * if they cut across existing structures * if they intrude parallel to features such as sedimentary strata
Discordant, concordant
51
Discordant bodies that serve as tabular conduits that transport magma toward Earth’s surface
Dikes
52
Concordant bodies that tend to accumulate magma and gradually increase in thickness
Sills
53
Large mass of intrusive igneous rock that forms from cooled magma > 100 km2
Batholith
54
Smaller plutons
Stocks
55
Igneous intrusion that has split apart two strata, resulting in a domelike structure Concordant pluton that has been injected between two layers of sedimentary rock
Laccolith
56
Plate motions provide the mechanisms by which mantle rocks undergo partial melting to generate magma. As hot rock rises, it experiences a decrease in confining pressure and mag undergo *
Decompression melting
57
the process which involves movements of the earth’s crust such that a portion id pushed up, push down or forced sideways
DIASTROPHISM

Earth Science (9 decks)

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