Chapter 5 Igneous Environments
____________is a measure of a material's resistance to flow
Viscosity
A very large pluton that covers more than 100 km2 is called a
batholith
Texture of Granite
coarse grained (phaneritic)
High temperature _____________ viscosity of magma
decreases
When lava solidifies (at or on the surface of the land), the rocks are classified as __________ igneous rocks
extrusive
Composition of Rhyolite
felsic
Texture of Andesite
fine grained (aphanitic)
The gradual increase in temperature with depth in the Earth is known as the
geothermal gradient
Texture of Obsidian
glassy
An example of a coarse grained igneous rock composed mostly of feldspar and quartz is called
granite
Felsic composition _____________ viscosity of magma
increases
Many mineral crystals _________ viscosity of magma
increases
Composition of Diorite
intermediate
Igneous rocks that form when magma solidifies deep beneath the surface of the land are called _________ igneous rocks
intrusive
Composition of Basalt
mafic
When melting forms magma
partial melting produces a magma that is more felsic than the source
An igneous rock with very coarse grained texture in which the minerals are centimeters long is called a
pegmatite
An igneous rock composed of two distinctly different sizes of mineral crystals with a fine-grained matrix around larger crystals is said to have a __________ texture
porphyritic
Which of the following rock types involves dissolved gas in the magma
pumice
Igneous rocks composed of rock fragments of pumice and hot volcanic ash are said to have a _____________ texture
pyroclastic/welded
Composition of Peridotite
ultramafic
Texture of Scoria
vesicular