Petrology Flashcards

1
Q

coarse, igneous
>90% plag
<10% olivine and pyx
what is the rock name?

A

Anorthosite

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2
Q

silica unsaturated plutonic rocks is called

A

Nepheline syenite

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3
Q

coarse, igneous
equal k-felds and plag

A

Monzonite

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4
Q

coarse, cryptocrystalline rock
<90% mafics
>60% felsics being foids

A

Foidolite

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5
Q

Monzogranite is often called

A

Adamellite

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6
Q

rare, coarse, crystalline, igneous
>90% quartz composed of felsic
<90% mafic minerals
hydrothermally altered (greisen)

A

Quartzolite

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7
Q

light colored granitoid
plag is <10% of total felds

A

Alkali-feldspar granite

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8
Q

K-felds/Total felds ratio is 0.35-0.90
20-60% quartz
coarse, holocrystalline, felsic, acidic, plutonic

A

Granite

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9
Q

granitoid
k-felds/total felds ratio 0.65-0.90
20-60% quartz

A

Syenogranite

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10
Q

k-felds/total felds is 0.35-0.65
often called adamellite

A

Monzogranite

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11
Q

20-60% quartz
plag is 65-90% total felds
intermediate bet. tonalite & granite containing quartz

A

Granodiorite

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12
Q

~ extrusive equivalent of granodiorite

A

rhyodacite

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13
Q

granitoid, plag >90% of total felds

A

Tonalite

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14
Q

syenitic-rock
no quartz
10% foids

A

Foid-bearing K-felds syenite

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15
Q

K-felds/Plag ratio 65-90%
5% quartz
intrusive equivalent of trachyte

A

Syenite

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16
Q

syenite
no quartz, <10% foids

A

Foid-bearning syenite

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17
Q

equal k-felds and plag
intermediate bet. syenite and diorite
quartz is minor or absent
intrusive equivalent of latite

A

Monzonite

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18
Q

dioritic
<5% quartz
10-35% K-felds

A

Monzodiorite

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19
Q

syenitoid
5-20% quartz
subequal k-felds and plag (35-65% of felds being plag)
no foids
coarse-grained equivalent of quartz-latite

A

Quartz-monzonite

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20
Q

gabbroid
felsic minerals less than 5% quartz or no foids
10-35% K-felds
optional term for a variety of granite having roughly equal amounts of k-felds and plag

A

Monzogabbro

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21
Q

dioritic
5-20% quartz
10-35% k-felds

A

Quartz monzodiorite

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22
Q

gabbro
felsic minerals compromising more than 5% quartz
10-35% k-felds

A

Quartz monzogabbro

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23
Q

gabbroid
10-90% Ca-dominant plag
>5% clinopyroxene
intrusive/coarse-grained equivalent of Basalt

A

Gabbro

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24
Q

mostly of calcic plag (>90% usually labradorite)
<10% mafics
lunar highlands are composed predominantly of this

A

Anorthosite

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25
Q

dioritic
0-10% quartz
10-35% k-felds

A

Quartz Diorite

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26
Q

gabbro
more than 5% quartz

A

Quartz gabbro

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27
Q

diorite
<10% foids
<10% k-felds

A

Foid-bearing diorite

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28
Q

gabbro
up to 10% foid minerals

A

Foid-bearing gabbro

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29
Q

foid-syenitic-rock
k-felds is >90%

A

Foid syenite

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30
Q

foid-syenitoid
k-felds is >50-90%

A

Foid monzonite

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31
Q

foid-dioritoid
k-felds is >50-10%

A

Foid monzodiorite

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32
Q

foid-rich rock
>60% of light coloured minerals are foids
coarse, crystalline
<90% mafics
>60% felsics being foids

A

Foidolite

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33
Q

family of rock-forming minerals
too little silica to form feldspar
not a true group

A

Foids (Feldspathoids)

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34
Q

Fine-grained equivalent of syenite

A

Trachyte

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35
Q

Fine-grained felsic igneous rocks lacking quartz, with felsics comprimosing 10-60% foids and k-felds/total felds >0.9

A

Phonolite

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36
Q

Fine-grained equivalent of diorite

A

Andesite

37
Q

fine-grained, igneous
felsics >20% quartz
<0.5 k-felds/plag

A

Dacite

38
Q

fine-grained, igneous
felsics 10-60% foids
k-felds/total felds <0.1
<10% olivine

A

Tephrite

39
Q

> 20% quartz
40-90% k-felds/plag
extrusive

A

Rhyolite

40
Q

> 20% quartz
<0.5 k-felds/plag
extrusive of granodiorite

A

Dacite

41
Q

0-5% quartz
0.65-0.90 k-felds/total felds
extrusive of syenite

A

Trachyte

42
Q

0-5% quartz
0.35-0.65 k-felds/total felds
extrusive of monzonite

A

Latite

43
Q

fine-grained equivalent of diorite
0-20% quartz
>65% felds being plag

A

Andesite

44
Q

general for fine-grained, mafic, igneous rocks
common - extrusive (volcanic)
locally intrusive (e.g. as dikes or pipe)
fine-grained equivalent of gabbro

A

Basalt

45
Q

10-60% foids
>0.9 k-felds/total felds
fine-grained equivalent of nepheline syenite

A

Phonolite

46
Q

10-60% foids
<0.1 k-felds/total felds
<10% olivine
extrusive equivalent of theralite

A

Tephrite

47
Q

tephritic rock
10-60% foids
<0.1 k-felds/total felds
>10% olivine
similar to tephrite but with little to no olivine
similar to basalt but little to no foids

A

Basanite

48
Q

<90% mafics
>90% foids of felsics

A

Foidite

49
Q

TAS stands for

A

Total Alkali versus Silica

50
Q

Classification scheme for volcanic rocks based on their bulk chemical composition

A

TAS diagram

51
Q

How are volcanic rocks classified

A

classified by their chemistry

52
Q

Why can’t volcanic rocks be classified by their mineralogy?

A

because the rocks is finely crystallized or even made of volcanic glass

53
Q

crystals so small they cannot be seen with the naked eye

A

Aphanitic

54
Q

phenocrysts contain numerous inclusions of another mineral that they enveloped with growth

A

Poikilitic

55
Q

plagioclase overgrowths on orthoclase (k-felds)

A

Rapakivi

56
Q

texture of andesite is commonly

A

Porphyritic

57
Q

common texture of komatite

A

Spinifex

58
Q

description of the degree of crystallinity, grain size and shape, and arrangement of minerals

A

Texture

59
Q

crystals visible to the naked eye

A

phaneritic

60
Q

coarse grained

A

3cm to 5mm

61
Q

medium grained

A

1-5 mm

62
Q

fine grained

A

< 1mm

63
Q

crystals so small they cannot be seen

A

Aphanitic

64
Q

composed entirely of crystals

A

Holocrystalline

65
Q

composed entirely of glass

A

Holohyaline

66
Q

composed of crystals and glass

A

Hypocrystalline

67
Q

phenocrysts set in a glassy groundmass

A

Vitrophyric

68
Q

phenocrysts contain numerous inclusions of another mineral that they enveloped with growth
host crystal is call an Oikocryst

A

Poikilitic

69
Q

holes in rock formed by escaping gases during solidification

A

Vesicles

70
Q

Rock that is Felsic and Phaneritic

A

Granite

71
Q

Intermediate, Phaneritic

A

Diorite

72
Q

Mafic, Phaneritic

A

Gabbro

73
Q

Felsic, Aphanitic

A

Rhyolite

74
Q

Aphanitic, Intermediate

A

Andesite

75
Q

Mafic, Aphanitic

A

Basalt

76
Q

Porphyritic, Felsic

A

Granite Porphyry

77
Q

Intermediate, Porphyritic

A

Andesite porphyry

78
Q

Mafic, porphyritic

A

Basalt porhyry

79
Q

ultramafic lava, such as precambrian komatiites, develop elongated olivine crystals
result of rapid growth of olivine in low viscosity magma, not by slow cooling

A

Spinifex

80
Q

preferred nucleation of one mineral on a preexisitng mineral
ex. growth of sillimanite on biotite or muscovite

A

Epitaxis

81
Q

plag overgrowths on orthoclase
occurs on some granites

A

Rapakivi

82
Q

in silicic volcanic rocks in w/c needles of quartz and k-felds grow rapidly from a common center

A

Spherulitic

83
Q

radiating plag lath in some basalts
probably the result of nucleation of later crystals on the first nuclei to form during devitrification of glass

A

Variolitic

84
Q

envelopment of plag lath by larger cpx and commonly interpreted to indicate that cpx formed late

A

Ophitic

85
Q

simultaneous crystallization of feldspar and quartz
intergrowth forms epitaxially on preexisting phenocrysts or dikelet walls

A

granophyre

86
Q

coarser version of granophyre

A

graphic

87
Q

evidence for advanced resorption, or rapid growth enveloping melt due to undercooling

A

sieve texture

88
Q

microphenocrysts of plag are aligned due to flow

A

Trachytic

89
Q

microphenocrysts are randomly oriented

A

Felty or pilotaxitic