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Flashcards in quiz 3 Deck (40)
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0

the difference between magma and lava is _____

that magma is found beneath the surface, whereas lava if found at the surface

1

igneous rocks _____

are formed through the cooling and crystallization of melt
can be produced at the surface of the earth as well as deep below the surface
are the most common type of rocks within earth

2

all other factors being equal intrusive rocks that form within earth ____ than intrusive rocks that cool near the surface.

cool more slowly

3

of the following which magma composition has the greatest silica content?

felsic

4

the formation of magma within earth is NOT caused by which of the proccesses

loss of volatiles to the atmosphere

5

important volatiles in magma include _____

water and carbon dioxide

6

if the volatile content of magma is increased its viscosity _____

decreases

7

most commonly felsic igneous rocks _____

are lighter in color than mafic rocks

8

a majority of the melts in the earth form through the partial melting of ultramafic mantle rock. these newly formed magmas are _______

mafic

9

when rock is partially melted, the chemistry of the melt is _____

more felsic than the original chemistry

10

magma tends to ______

move upward, away from where it formed

11

if a volcano erupted and its resultant lava flowed to a great distance at a relatively fast rate, what properties would you expect of the lava?

high temp
volatile rich
mafic

12

if a body of magma becomes more felsic its viscosity will _____

increase

13

viscosity depends on _____

temp
volatile content
silica content

14

due to frictional crystallization and assimilation of surrounding host rock, most magmas that rise slowly through the crust chemically evolve to become ______

more felsic

15

if a body of magma is subjected to fractional crystallization, the rock that results is expected to be _____

more mafic than the magma

16

a blob-like igneous rock body that has cooled beneath the surface of earth is ____

pluton

17

a dike is a(an) _____

tabular (sheet like) intrusion that cuts across preexisting layers

18

bombs, ash, and cinders are all examples of _____

pyroclastic debris

19

as compared to aphanitic igneous rocks phaneritic rocks are ______

made of crystals big enough to see

20

an igneous rock with mixed texture of coarse grains (phenocrysts) surrounded by fine crystals (groundmass) is termed ____

porphyritic

21

the silicate mineral that is found in the greatest variety of igneous rocks is _____

plagioclase feldspar

22

if you determine the composition of an igneous rock, you can deduce a number of things about the rock's origin. which one these is NOT one of those things?

the exact age of the rock

23

coarse-grained granite is most similar in mineral compositioon to fine-grained _______

rhyolite

24

a volcanic island arc occurs at _____

the Aleutian Islands of Alaska

25

which of the following would help distinguish continetal hot spots from oceanic hot spots?

the presence of both mafic and felsic magmas

26

in 79 ce, the citizens of pompeii in the Roman Empire were buried by pyroclastic debris derived from an eruption of _____

mt. vesuvius

27

a fast moving flow consisting of a mixture of water and volcaniclastic debris is called a ______

lahar

28

the smoky cloud that rises from the vent of an actively erupting volcano is composed of ______

fine volvaniclastic debris (ash) suspended in the air

29

common volcanic gases include_______

water vapor, carbon dioxide, and sulfer dioxide