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

To explain the great volumes of granite plutonic rocks, most geologists think that partial melting of the _______ must take place.

______ are extremely coarse-grained with crystal up to 10 meters across.

Most of the basalt and gabbro on the ocean floor is created at mid oceanic ridges, which are also ____.

______ is the predominant igneous rock of the continents.

The geothermal gradient, on average, is about _____.

The geothermal gradient for a volcanic region is greater than that for the continental interior.

What type of melting takes place when a body of hot mantle rock moves upward and the pressure is reducted to the extent that the melting point drops to the temperature of the body?

The most common minerals in a granite are the ______.

The sequence in which minerals crystallize in a cooling igneous melt is called Bowen's Reaction Series.

How is a sill different from a dike?

Basaltic magmas crystallize at higher temperatures than granitic magmas.

___ is a coarse-grained igneous rock (grains > 1 mm diameter) with visible grains of quartz.

Hawaii and __________ eruptions are related to intraplate igneous activity.

Diorite and andesite are composed of similar amounts of feldspars and ferromagnesian minerals.

A useful tool illustrating the relationships among igneous, sedimentary, and metamorphic rocks is called the ___.

The continuous branch in Bowen's Reaction Series contains the ferromagnesian minerals.

The first plagioclase crystals to form as a hot melt cools are high in ______.

Mineralogically and chemically equivalent rocks are ___ and __.

Partial melting of the lower continental crust produces a silicic magma that eventually solidifies into granite or rhyolite.

The coarse-grained equivalent of basalt is a(n) ______.