Physical Geology 101
Igneous Rocks Study Guide


After the "Igneous Rocks" lecture and readings you should be able to answer and discuss the following questions.

What does the word igneous mean?

What is magma?

What things or conditions are needed to produce a magma?

What are the sources of heat which can producing melting?

Describe specifically what happens during the melting process.

How can changes in pressure result in the melting of a rock?

Why does the addition of volatiles result in a lowering of the melting temperature?

What are the most common volatiles found in magma?

What is the process of partial melting and why is it important in the production of magma?

What is crystallization?

What are the means by which temperature is decreased during the crystallization process?

What is the Bowen's Reaction Series?

How does the Bowen's Reaction Series relate to temperature and composition?

What are the origins of the words Plutonic and Volcanic?

List and describe the plutonic textures.

List and describe the volcanic textures.

What does a phaneritic texture tell us about the origin of an igneous rock?

What does an aphanitic texture tell us about the origin of an igneous rock?

What is SiO2?

What is the Color Rule for identification of composition?

What are the chemical characteristics of an ultramafic composition?

What are the chemical characteristics of a mafic composition?

What are the chemical characteristics of an intermediate composition?

What are the chemical characteristics of a felsic composition?

What are the exceptions to the color rule?

Practice identifying Igneous Rocks: Igneous Rocks Identification