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geology > chapter 3 igneous and intrinsic activity > Flashcards

chapter 3 igneous and intrinsic activity Flashcards

1
Q

____ produced of entirely igneous rocks

A

mantle

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2
Q

____ : parent material for igneous rocks

A

magma

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3
Q

magma component: composed of the earth most common components

A

liquid- “melt”

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4
Q

magma component: possibly absent: crystal and silicates

A

solid

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5
Q

magma component: volatiles- vaporize at surface pressures- H20, Co2, So2

A

Gas

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6
Q

as temperature increases magma becomes ________, if it continues to increase bonds _____ and rock ______

A

crystaline rock, become destroyed, melts

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7
Q

Cooling reverses the events of melting. liquid melt —> organised solid structure

A

crystalization

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8
Q

Chem comp, # of volatiles, rate of colling

A

How magmas differ

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9
Q

when magma solidifies it creates ___ rocks

A

Intrusive igneous

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10
Q

lava cools in surface creating ____ rocks

A

extrusive igneous

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11
Q

Texture and crystal visibility of intrusive igneous rocks

A

course-grained + visible crystals

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12
Q

Texture and crystal visibility of extrusive igneous rocks

A

fine-grained + volcanic debris

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13
Q

Feldspar and quartz dominant rocks

A

felsic rocks

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14
Q

category of igneous rocks with around 10% dark silicate minerals (usually biotite or amphisole)

A

felsic rocks

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15
Q

category of igneous rocks that are the major constituants of the earths crust

A

felsic rocks

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16
Q

Category of igneous rock that has at least 25% dark silicates (usually amphibole, pyroxene, and biotite mica or plagioclase feldspar

A

Andesetic (intermediate)

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17
Q

Category of igneous rock that contain dark silicate minerals and plagiocase feldspar

A

Mafic

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18
Q

Category of igneous rock that typically darker and denser than granitic rock

A

Mafic

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19
Q

category of igneous rock that has many dark silicates (usually olivine and pyroxene) ex. peridiodite

A

ULTRAMAFIC

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20
Q

Granitic Magma has _____ therefore is thicker

A

more silicates

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21
Q

Basaltic Magma has _____ therefore is smoother

A

less silicates

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22
Q

Texture of igneous rock as a result of very rapid cooling ex. Pumis (ash)

A

Glassy

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23
Q

Texture of igneous rock as a result of being debris of eruption, with fine fragments of glass instead of interlocking crystals

A

pyroclastic

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24
Q

Texture of igneous rock as a result of lava cooling quickly (fine-grained)

A

Aphanatic

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25
Q

Texture of igneous rock where the rate of cooling starts slow then speeds up, classified by the observation of large crystals surrounded by small crystals

A

poryphyritic

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26
Q

Texture of igneous rock classified by the presence of large interlocking crystals surrounded by small crystals. The small crystals are called _____

A

pegmatatic, groundmass

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27
Q

Texture of igneous rock classified by the creation from the cooling of magma at depth (coarse-grained)

A

Phaneric

28
Q

Rock that is phanaretic and felsic

A

Granite

29
Q

Rock that is phaneretic and intermediate

A

Diorite

30
Q

Rock that is phaneretic and mafic

A

Gabbro

31
Q

Rock that is Aphanatic and felsic

A

Rhyolite

32
Q

Rock that is Aphanatic and intermediate

A

Andesite

33
Q

Rock that is Aphanatic and Mafic

A

Basalt

34
Q

Rock that is Poryphitic and Felsic

A

Granite porphyry

35
Q

Rock that is Poryphitic and intermediate

A

Andesite porphyry

36
Q

Rock that is Poryphitic and Mafic

A

Basalt Porphyry

37
Q

Most magma originates when essentially solid rock, located in the crust and upper mantle, _____

A

melts

38
Q

This increase in temperature with depth, known as the _____

A

geothermal gradient

39
Q

Melting, which is accompanied by an increase in volume, occurs at higher temperatures at depth because of ________

A

greater confining pressure

40
Q

Conversely, reducing confining pressure _______

A

lowers a rock’s melting temperature

41
Q

when confining pressure drops sufficiently __________

A

decompression melting is triggered

42
Q

Decompression melting occurs where hot, solid mantle rock ______

A

ascends in zones of convective upwelling

43
Q

As an oceanic plate sinks __________

A

both heat and pressure drive water from the subducting crustal rocks

44
Q

Melting of peridotite generates _____ magma

A

basaltic

45
Q

In summary, magma can be generated three ways:

A

(1) when an increase in temperature causes a rock to exceed
its melting point; (2) in zones of upwelling a decrease in pressure
(without the addition of heat) can result in decompression melting; and (3) the introduction of volatiles (principally water) can lower the melting temperature of hot mantle rock sufficiently to generate magma

46
Q

basaltic magma crystallizes over
a range of at least ____

A

200 °C of cooling

47
Q

______ process occurs when the earlier-formed minerals are more dense (heavier) than the liquid portion and sink toward the bot- tom of the magma chamber

A

crystal settling

48
Q

The formation of one or more secondary magmas from a single parent magma is called _______

A

magmatic differentiation

49
Q

Once a magma body forms its composition can also change through the incorporation of foreign material. For example, as magma migrates through the crust, it may incorporate some of the surrounding host rock, a process called ________

A

assimilation

50
Q

This process occurs when one magma body intrudes another that has a different composition

A

magma mixing

51
Q

he incomplete melting of rocks is known as ________, a process that produces most magma

A

partial melting

52
Q

When magma rises through the crust, it forcefully displaces preexisting crustal rocks referred to _________

A

as host or country rock.

53
Q

The structures that result from the emplacement of magma into preexisting rocks are called ________

A

intrusions or plutons

54
Q

Igneous bodies are said to be ________ if they cut across existing structures

A

discordant

55
Q

Igneous bodies are said to be ________ if they form poarallel to features such as sedimentary strata

A

concordant

56
Q

_____ are discordant bodies that cut across bedding surfaces or other structures in the host rock.

A

dikes

57
Q

_____ are nearly horizontal, concordant bodies that form when magma exploits weak- nesses between sedimentary beds

A

sills

58
Q

________ form as igneous rocks cool and develop shrinkage fractures that produce elongated, pillar-like columns.

A

Columnar joints

59
Q

By far the largest intrusive igneous bodies are _______

A

batholiths

60
Q

When molten material is quenched instantly, a mass of unordered atoms, referred to as ____, forms

A

glass

61
Q

Rocks of intermediate compsition, (e.g., andesite and diorite) are rich in plagioclase ______

A

feldspar and amphibole

62
Q

“Strange rock”
- Rock embedded in a seperate matrix

A

xenolith

63
Q

Melting mechanisms
- Mid Ocean Ridge

A
  • Hot material is brought to the surface
64
Q

Melting mechanisms
-Hotspot (mantle plume)

A

Adds heat to the base of the lithosphere

65
Q

Melting mechanisms
-Subduction zone

A

A subducting plate brings water with it, thereby decreasing the melting point of the other plate

66
Q
A

geology (7 decks)

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