Exam 3: Igneous Rocks, Intrusive Activity, and the Origin of Igneous Rocks

_____, a coarse-grained rock composed of pyroxene and olivine, is the most abundant ultramafic rock.

On its slow journey through the crust, mafic magma evolves into intermediate magma by differentiation and assimilation of ______.

Igneous rocks that are silica-rich with high aluminum, sodium, and potassium are _____ rocks.

The huge volume of mafic magma that erupted to form the Columbia plateau basalts of Washington and Oregon are attributed to ___.

________ lava is largely restricted to narrow zones along convergent plate boundaries.

The melting point of a rock decreases with increasing pressure.

The melting point of a mineral generally _____ with increasing pressure (or depth).

Fine-grained igneous rocks (grains < 1.0 mm) that have small grains cooled rapidly and are likely to be _______.

A _______ is a tabular (thin but large area) intrusive body that is concordant (parallel to the host rock structure).

Under ideal conditions rock can melt and yield a granite composition at temperatures as low as ___.

What is the process through which magma differentiation takes place?

A ______ is an intrusive structure that formed from magma that solidified within the "throat" of a volcano.

Pegmatites are extremely coarse-grained igneous rocks.

Extrusive igneous rocks are typically fine grained because they crystallized slowly, deep below the Earth's surface.

The crust beneath the world's oceans is mafic ________.

______ igneous rocks, like gabbro and basalt, are silica-deficient with high magnesium and iron.

___ are igneous rocks that are silica-deficient but high in iron and magnesium.

Imagine two magmas that are identical in all respects (for example, same chemistry, pressure, volume) except that one magma is hotter than the other. Which magma will have the higher viscosity?

Both andesite and ___ are composed of feldspars and 30% to 50% ferromagnesian minerals.

Crystal settling accounts for important deposits of ______.