Evidence is accumulating to suggest that small inputs of magnetic gas could be an important, unrecognized parameter that might be used to classify and understand systems that are otherwise similar. Coupled analyses of gas abundances and isotopic compositions will be made of fluid inclusions from several deposits that might have received inputs of magnetic gas, including Comstock, Nevada and Hishikari, Japan. Analyses will also be made of vapor-rich inclusions from porphyry copper and acid-sulfate deposits. The study will be guided by results of gas and isotopic analyses of materials from active geothermal systems. This should impact our understanding of both active and fossil hydrothermal systems.
