| Composition |
Intrusive (Plutonic)
Rock Type
(Coarse-grained due to slow cooling) |
Extrusive (Volcanic)
Rock Type
(Fine-grained due to rapid cooling) |
Minerals (Bowen's Reaction Series) |
Crystallization
Temperature |
Color |
SiO2 wt% |
K2O wt% |
H2O wt% |
Density |
Viscosity |
Volcano Type |
Explosiveness |
| Ultramafic |
Peridotite |
None |
Discontinuous Branch Continuous Branch
Olivine Ca-rich
\ /
Pyroxene /
\ Plagioclase
Amphibole /
\ /
Biotite Na-rich
\ /
Orthoclase
Muscovite
Quartz
|
1300oC |
green |
45 |
very low |
low |
very high > 3.2 grams/cm3 |
low |
NA |
NA |
| Mafic |
Gabbro |
Basalt |
1200oC |
dark
dark green
to black |
50-60 |
low |
low |
high ~3.0 grams/cm3 |
low |
Shield Volcanoes
(also cinder cones) |
low |
| Intermediate |
Diorite |
Andesite |
1000oC |
gray
salt & pepper |
60-70 |
intermediate |
intermediate |
intermediate ~2.8 grams/cm3 |
intermediate |
Stratovolcanoes
(Composite Volcanoes) |
moderate to high |
| Felsic |
Granite |
Rhyolite |
750oC |
light
white or pink |
70-75 |
high |
high |
low ~2.65 grams/cm3 |
high |
Stratovolcanoes and
Continental Calderas |
high |
