Chapters 10 and 11 cover igneous activity. Either may be read before the other. Chapter 10 emphasizes intrusive activity, but it also covers igneous rock classification and the origin of magmas, which are applicable both to volcanic and intrusive phenomena. Chaper 11 concentrates on volcnoes and related extrusive activity.

Volcanic eruptions, while awesome natural spectacles, also provide important information on the workings of the Earth's interior. Volcanic eruptions vary in nature and in degree of explosvie violence. A srong correlation exists between the chemical composition of magma (or lava) and the violence of an eruption. The size and shape of volcanoes and lava flows and their pattern of distribution on the Earth's surface also correspond to the composition of their lavas.

Understanding volcanism provides a background for theories relating to mountain building, the development and evolution of continental and oceanic crust, and how the crust is deformed. Our observations of volcanic activity fit nicely into plate-tectonic theory as described in chapter 10.

HOT! How did you spend your summer vacation? HOT!
Click on the link below to share the experiences of Geoscience students from the University of Arkansas and their professor, Dr. Glen Mattioli, as they survive an explosive volcanic eruption on the Caribbean island of Montserrat during July 2003.

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::Montserrat, October 1997::http://comp.uark.edu/~mattioli/redo_plume3.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif">Montserrat, October 1997 (33574K)</a>Montserrat, October 1997

View Dr. Mattioli's photographs of the eruption and its aftermath here, here, or here.

Read a press release about the eruption here.

Read another press release about the eruption here.

Learn more about the Soufriere Hills volcano here.

Learn about the CALIPSO project here.

Contact the University of Arkansas Department of Geosciences here.