MAGMATIC VOLATILE COMPONENTS AND THEIR ROLE IN THE FORMATION OF ORE-FORMING FLUIDS

Data on the average contents of the most abundant volatile elements (H 2O, CO2, S, Cl, and F) in magmatic melts of various rocks-from ultraba sic to acid-are reviewed. Many publications containing contents on dis tribution of volatile and petrogenic components of magmatic silicate m elts have been summarized The contents were obtained by analyses of gl asses of homogenous melt inclusions in minerals and quenched glasses o f volcanic rocks from the ocean floor. The numbers of determinations f or the above components are: H2O-1365, Cl-357, F-833, S-655, and CO2-3 38. The average contents of volatile components and their ratios were calculated taking into account the abundance of various types of magma tic melts in the continental crust, continental margins, and ocean flo or. Data on temperatures and pressures of magmatic fluids (more than 6 00 determinations) are given. On the examples of a number of hydrother mal ore mineralization processes, the role of magmatic volatile compon ents in the formation of ore-forming fluids is discussed.