Petrology Flashcards
coarse, igneous
>90% plag
<10% olivine and pyx
what is the rock name?
Anorthosite
silica unsaturated plutonic rocks is called
Nepheline syenite
coarse, igneous
equal k-felds and plag
Monzonite
coarse, cryptocrystalline rock
<90% mafics
>60% felsics being foids
Foidolite
Monzogranite is often called
Adamellite
rare, coarse, crystalline, igneous
>90% quartz composed of felsic
<90% mafic minerals
hydrothermally altered (greisen)
Quartzolite
light colored granitoid
plag is <10% of total felds
Alkali-feldspar granite
K-felds/Total felds ratio is 0.35-0.90
20-60% quartz
coarse, holocrystalline, felsic, acidic, plutonic
Granite
granitoid
k-felds/total felds ratio 0.65-0.90
20-60% quartz
Syenogranite
k-felds/total felds is 0.35-0.65
often called adamellite
Monzogranite
20-60% quartz
plag is 65-90% total felds
intermediate bet. tonalite & granite containing quartz
Granodiorite
~ extrusive equivalent of granodiorite
rhyodacite
granitoid, plag >90% of total felds
Tonalite
syenitic-rock
no quartz
10% foids
Foid-bearing K-felds syenite
K-felds/Plag ratio 65-90%
5% quartz
intrusive equivalent of trachyte
Syenite
syenite
no quartz, <10% foids
Foid-bearning syenite
equal k-felds and plag
intermediate bet. syenite and diorite
quartz is minor or absent
intrusive equivalent of latite
Monzonite
dioritic
<5% quartz
10-35% K-felds
Monzodiorite
syenitoid
5-20% quartz
subequal k-felds and plag (35-65% of felds being plag)
no foids
coarse-grained equivalent of quartz-latite
Quartz-monzonite
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
Monzogabbro
dioritic
5-20% quartz
10-35% k-felds
Quartz monzodiorite
gabbro
felsic minerals compromising more than 5% quartz
10-35% k-felds
Quartz monzogabbro
gabbroid
10-90% Ca-dominant plag
>5% clinopyroxene
intrusive/coarse-grained equivalent of Basalt
Gabbro
mostly of calcic plag (>90% usually labradorite)
<10% mafics
lunar highlands are composed predominantly of this
Anorthosite
dioritic
0-10% quartz
10-35% k-felds
Quartz Diorite
gabbro
more than 5% quartz
Quartz gabbro
diorite
<10% foids
<10% k-felds
Foid-bearing diorite
gabbro
up to 10% foid minerals
Foid-bearing gabbro
foid-syenitic-rock
k-felds is >90%
Foid syenite
foid-syenitoid
k-felds is >50-90%
Foid monzonite
foid-dioritoid
k-felds is >50-10%
Foid monzodiorite
foid-rich rock
>60% of light coloured minerals are foids
coarse, crystalline
<90% mafics
>60% felsics being foids
Foidolite
family of rock-forming minerals
too little silica to form feldspar
not a true group
Foids (Feldspathoids)
Fine-grained equivalent of syenite
Trachyte
Fine-grained felsic igneous rocks lacking quartz, with felsics comprimosing 10-60% foids and k-felds/total felds >0.9
Phonolite