This course provides an introduction to the physical, chemical, mineralogical, and petrographic characteristics of igneous rocks. At the end of this course, students will have a broad understanding of the processes involved in magma generation, differentiation and crystallization. They will also learn about the abundance and distribution of various types of igneous rocks and how they relate to planetary evolution and plate tectonics. Phase diagrams will be used to explain how minerals change composition as magmas cool and solidify and also to explain how magmas are generated by partial melting of crystalline assemblages. The role of volatiles in melting processes, volcanic eruptions and volcanic degassing will be discussed. The standard schemes of rock classification will be explained and applied. The laboratory component requires good understanding of optical mineralogy and involves detailed observation and description of a variety of igneous rocks. PREREQ: GEOL 2127 and GEOL 2237. (lec 3, lab 3) cr 3.