Exam 4: Igneous Rocks and Intrusive Igneous Activity

In igneous rocks with porphyritic texture, the larger minerals are phenocrysts, and the smaller minerals collectively make up the groundmass.

A vesicular felsic rock is called a:

____________________ are concordant, mushroom-shaped plutons.

Basalt and gabbro are compositional equivalents, which means that they are made up of the same ____________________ but have different ____________________.

Mantle plumes are the cause of linear volcanic chains and probably flood basalts.

When magma cools rapidly, crystal growth proceeds at a relatively ____________________ rate and the resultant rock is ____________________ in texture.

Bowen's reaction series explains the order of mineral formation with decreasing temperature.

Briefly explain batholith formation.

Why does lava retain heat so well?

How do the holes form in vesicular igneous rocks, such as scoria and pumice?

What does a mantle plume result in?

Why can an intruding mafic magma assimilate felsic country rock, but an intruding felsic magma cannot assimilate mafic country rock?

Briefly explain why felsic intrusive rocks are actually more common than mafic intrusive rocks.

Erupting lavas generally have a temperature in the range of 700 ° to 1200 ° F.

What does a porphyritic texture tell us about the history of an igneous rock?

The process of assimilation includes the incorporation of felsic country rock.

The mineral having the lowest melting point in the Bowen's reaction series is olivine.

The process of assimilation partly explains why felsic intrusive rocks are much more common than mafic intrusive rocks.

Bowen's reaction series explains why Si-rich minerals are the last to crystallize from a magma.

What is a mantle plume, and what causes one to erupt?