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

Geologists regard basaltic magma (Hawaiian lava, for example) as the result of the partial melting of ultramafic rock in the ____.

Mafic magma generated in the _______ rises to the base of the crust.

Ultramafic igneous rocks are composed almost entirely of __.

Viscosity is a property of a fluid that relates to how easily the fluid flows. A material that is viscous __.

Although batholiths may contain mafic and intermediate rocks, they almost never composed of granite.

A pluton is an igneous structure that crystallized at very shallow depths.

An ultramafic rock is composed almost entirely of quartz.

Rhyolite is considerably more common than granite.

The term mafic comes from the terms magnesium and ferric.

Igneous rocks may be either ____ if they form on or near Earth's surface, or ___ if they solidify under ground.

Granite and ______ are composed predominantly of feldspar and quartz.

A mineral's melting point generally increases with increasing pressure.

The geothermal gradient is the rate at which pressure increases with increasing depth beneath the surface.

Igneous rock names are based on grain shape and chemical composition.

A dike is a discordant intrusive igneous structure.

______ are fragments of country rock that are distinct from the body of igneous rocks in which they are enclosed.

What is the sequence of crystallization along the discontinuous branch of Bowen's reaction series?

Lava is magma on the Earth's surface.

_____ rocks have coarse crystals in a fine-grained matrix.

Mafic igneous rocks are silica-poor.