3.1 - IN GREATER DEPTH
PEGMATITE - A ROCK MADE OF GIANT CRYSTALS - Extremely coarse textured igneous bodies are associated with some granitic intrusions, although they can form in rocks of any composition. They represent slow cooling of a low viscosity fluid, probably water under high pressure. The water contains ions that crystallize into potassium and sodium feldspars, micas and quartz, but unusual and rare minerals, such as lithium micas, uranium ores and gemstones, can also form. Pegmatites occur as pod-like bodies, if trapped within the magma chamber, or hydrothermal veins above the intrusion, if cracks in the country rock allow the fluid to escape.

3.2 - ENVIRONMENTAL GEOLOGY
HARNESSING MAGMATIC ENERGY - Magma chambers in the United States have the potential to provide 5,000 times the energy consumed by the country each year based on estimates from the U. S. Geological Survey. This magmatic energy would be in the form of electricity produced from steam generated by circulating water into the chambers. Progress in utilizing this energy has been slow because of problems with drilling and the potential creation of-unwanted volcanic eruptions.

3.3- IN GREATER DEPTH
ALTERNATIVE- HYPOTHESES FOR GENERATION OF ANDESITIC AND GRANITIC MAGMAS - Production of felsic and intermediate magmas at converging plate boundaries is controversial and undergoing scrutiny. Three explanations have been provided to explain these magmas: 1) partial melting of basalt - subducting oceanic crust would initially release intermediate magmas, but not produce much granite; 2) crustal assimilation - mafic magmas moving through continental crust would absorb more silica-rich rocks and change composition to intermediate; and 3) melting sedimentary rocks - sedimentary dragged along with subducting oceanic lithosphere could form felsic magmas upon melting or mix with mafic magmas to form intermediate compositions.