IUGS Classification Coarse Grain/ Texture Flashcards

1
Q

Quartz compromise more than 90% of the felsic minerals, and has <90% mafic minerals. It may be hydrothermally altered granitoids (e.g. greisen)

A

Quartzolite

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2
Q

A light colored mineral where plagioclase is less than 10% of the total feldspar.

A

Alkali-feldspar granite

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3
Q

An alkali-feldspar/ total feldspar ratio from 0.35-0.90 on the QAFP diagram and 20 - 60% quartz

A

Granite

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4
Q

An alkali-feldspar/ total feldspar ratio from 0.65 - 0.90 and 20 - 60 quartz

A

Syenogranite

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5
Q

An alkali-feldspar/ total feldspar ratio from 0.35-0.65 on the QAFP diagram. Often called adamellite.

A

Monzogranite

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6
Q

It has 20-60% quartz and a plagioclase of 65-90% of the total feldspar.

A

Grandiorite

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7
Q

A granitoid, where plagioclase is >90%

A

Tomalite

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8
Q

Plagioclase is less than 10% of the total feldspar

A

Alkali-feldspar syenite

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9
Q

No quartz and containing up to 10% foids

A

Foid-bearing alkali feldspar syenite

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10
Q

Alkali-feldspar/ plagioclase ratio from 65-90% and <5% quartz. Intrusive equivalent of ‘trachyte’

A

Syenite

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11
Q

No quartz and <10% foids

A

Foid-bearing syenite

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12
Q

Equal amounts of alkali feldspar and plagioclase, and thus intermediate between diorite and syenite. Intrusive equivalent og latite.

A

Monzonite

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13
Q

Dioritic rock with <5% quartz and 10-35% alkali feldspar on the QAFP diagram.

A

Monzodiorite

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14
Q

A syenitoid with 5-20% quartz and subequal K-feldspar and plagioclase (35-65% of the feldspar being plagioclase). Coarse-grained equivalent of quartz-latite.

A

Quartz-monzonite

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15
Q

Less than 5% quartz or no foids, and no 10-35% K-feldspar.

A

Monzogabbro

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16
Q

Dioritic rock with 5-20% quartz and 10-35% alkali feldspar.

A

Quartz monzodiorite

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17
Q

More than 5% quartz and 10-35% K-Feldspar

A

Quartz monzogabbro

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18
Q

Foid-dioritoid where K-feldspar is >50-10% of feldspar

A

Foid monzodiorite

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19
Q

Foid gabbroic rock where plagioclase is 50-90% of feldspar

A

Foid monzogabbro

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20
Q

<5% quartz and <10% alkali feldspar on the QAFP diagram

A

Diorite

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21
Q

Composed of 10-90% Ca-dominant plagioclase and >5% clinopyroxene

22
Q

Mostly of calcic plagioclase (>90% usually labradiorite) with <10% mafics

A

Anorthosite

23
Q

Dioritic rock with 0-10% quartz and 10-35% alkali feldspar.

A

Quartz Diorite

24
Q

Gabbro with felsic minerals comprising more than 5% quartz

A

Quartz Gabbro

25
Diorite with <10% foids and <10% alkali feldspar
Foid-bearing diorite
26
Gabbro containing up to 10% foid minerals
Foid-bearing gabbro
27
Rock where K-feldspar is >90%
Foid syenite
28
Foid-syenitoid where K-feldspar is >50-90% of feldspar
Foid monzosyenite
29
Foid-dioritoid where k-feldspar is 50-90%
Foid monzodiorite
30
Plagioclase is >90% of feldspar
Foid diorite
31
Rock with <90% mafics, >60% of felsic being foids
Foidolite
32
Minerals consisting of aluminosilicates of sodium, potassium, or calcium and having too little silica to form feldspar.
Foids (feldspathoids)
33
and Enumerate the common foid mineralss
Analcime Leucite Nepheline Sodalite
34
Crystals visible to the naked eye.
Phaneritic
35
Crystals so small that they cannot be seen with the naked eye
Aphanitic
36
Composed entirely of crystals
Holocrystalline
37
Composed entirely of glass
Holohyaline
38
Composed of crystal and glass
Hypocrytalline
39
Phenocrysts set in a glassy groundmass
Vitrophyric
40
Phenocrysts containing numerous inclusion of another mineral that they enveloped with growth.
Poikilitic
41
Host crystal of poikilitc is termed as _________.
Poikilitc
42
Holes in the rock formed by escaping gases during solidification
Vesicle
43
Result of rapid growth of olivine and develop elongated olivine crystals
Spinifex texture
44
Nucleation of one mineral on a preexisting mineral e.g. growth of sillimanite on biotite or muscovite
Epitaxis texture
45
Plagioclase overgrowths on orthoclase (K-feldspar)
Rapakivi texture
46
In silicic volcanic rocks in which needles of quartz and alkali feldspar growth radially from a common center
Spherulitic texture
47
Refers to the envelopment of plagioclase laths by larger larger clinopyroxene and is commonly interpreted to indicate that clinopyroxene formed later.
Ophitic texture
48
Radiating plagioclase laths in some basalts are probably the result of nucleation of later crystals on the first nuclei to form during devitrification of glass
Variolitic texture
49
Evidence for advanced resorption, or rapid growth enveloping melt due to undercooling
Sieve texture
50
Result from simultaneous crystallization of feldspar and quartz, the intergrowth forms epitaxially preexisitng phenocrysts or dikelet walls
Granophyre and Graphic Texture