9725072 Webster The proposed study will determine compositions of granitic, pegmatitic, and aplitic liquids that generated tin and tungsten mineralization in the historic Erzgebirge mountains of southern Germany and will investigate the evolution of granitic to pegmatitic and aplitic liquids by analyzing silicate melt inclusions in rocks from several mineralized systems in this mining district. Particular attention will be directed at the behavior of the volatiles water, fluorine, chlorine, phosphorus, and boron, because these constituents exert strong controls on magmatic processes and concomitant processes of hydrothermal alteration and ore formation. Another goals of the study will be to determine the abundances of the ore metals tin and tungsten in the silicate melt inclusions. The melt inclusions will be analyed by electron and ion microprobes and infrared spectroscopy. The behavior of tin in mineralizing, magmatic systems will be investigated through experimental study of the dissolution of cassiterite (the chief ore mineral of tin) in granitic liquids that are variably enriched in fluorine, water, and phosphorus. The results of these investigations are important for understanding how granitic liquids evolve, form pegmatite and aplite facies, and generate tin and tungsten ore deposits.
