Exam 8: Volcanoes and Plutons

Long chains of silicate tetrahedra form in magma with __________ composition.

Magma with a high water content has a greater tendency to __________ in the crust, compared with magma with a lower water content.

A cinder cone is usually active for only a short period of time because once the gas escapes the driving force behind the eruption is removed.

The three environments of magma production are __________ __________, __________ __________, and __________ __________.

Oceanic crust is typically of __________ composition.

The magma type that most commonly rises to the Earth's surface to erupt from a volcano is:

Most basaltic magma erupts at the Earth's surface because it:

Which of the following tectonic environments does not generate large quantities of magma?

Melting caused by decreased pressure is called __________ melting.

Regional predictions can be used to determine exactly when a particular volcano will erupt.

The circular depression left when the roof of a magma chamber collapses is called a/an __________.

Which of the following processes causes melting of the asthenosphere and the generation of magma?

The magma of andesite and diorite contains __________ silica than granite.

The higher silica content of granitic magma causes it to:

A __________ is a pluton with an outcrop area of less than 100 square kilometers.

Basaltic magma forms at the Mid-Oceanic Ridge.

The Columbia River plateau is an example of a lava plateau.

Which magma type erupts most violently?

A shield volcano commonly erupts when:

A/an __________ is a crater formed by the collapse of a magma chamber.