ABSTRACT
Rhyolites and their deep-seated chemical equivalents, granites, are some of the most interesting rocks. They provide good examples of why it is important to look carefully at fresh rocks in terms of fıeld relationships, mineralogy, petrography, petrology, geochemistry, and alteration processes. Because of their evolved geochemisty, they commonly are important in terms of ore-forming processes. They are almost certainly the source of metal in many beryllium and lithium deposits and the source of heat for many other hydrothermal systems. From other perspectives, rhyolitic volcanic eruptions have the capacity of destroying civilizations, and their geochemistry (e.g., high contents of radioactive elements) is relevant to public policy decision-making.
Environment Health Risks and Public Policy: Decision Making in Free Societies
