FORMATION OF CARBON AND HYDROGEN SPECIES IN MAGMAS AT LOW OXYGEN FUGACITY

Abstract

Studies of iron-bearing silicate melt (ferrobasalt) þ iron metallicphase þ graphite þ hydrogen equilibria show that carbon andhydrogen solubilities in melts are important for the evolution of theupper mantle. In a series of experiments conducted at 3 7GPa and1520--- 1600 C, we have characterized the nature (oxidized vsreduced) and quantified the abundances of C- and H-compoundsdissolvediniron-bearingsilicatemelts.Experimentswerecarried outin an anvil-with-hole apparatus permitting the achievement of equalchemical potentials of H