Experimental Study On The Hydrogen Partition Coefficient Between Clinopyroxene And Melt In Continental Basalt

At1.5－5GPa,1100－1200℃and different oxygen fugacity condition, the meltexperiments using the Continental Alkali Basalt+6wt.%deionized water wereconducted in a walker-type multi-anvil press. The Fourier Transform InfraredSpectroscopy and Laser Raman Spectroscopy were separately used to analyze thewater contents of clinopyroxene and melt, then the hydrogen partition coefficientsbetween clinopyroxene and melt(D_OH^Cpx/Melt)) were got at different experimentalconditions. The following remarkable results were obtained,1. Under given temperature and oxygen fugacity conditions, D_OH^Cpx/Melt increasedwith pressure below3.0GPa, while it decreased with pressure above3.0GPa.2. Under given temperature and pressure conditions, oxygen fugacity had animportant influence on D_OH^Cpx/Melt,which increased with oxygen fugacity. When the Nifilm was used as the oxygen buffer,D_OH^Cpx/Melt was the maximum, and it is0.0218.3. Under given pressure and oxygen fugacity conditions, D_OH^Cpx/Melt decreasedwith temperature. When the temperature increased from1100℃to1200℃,D_OH^Cpx/Melt decreased from0.0218to0.0144.The results could be used to explain the hydrogen fractionation during thepyrolite melting process with hydrogen partition coefficient between other NominallyAnhydrous Minerals(Such As, olivine, orthopyroxene, garnet and spinel) andMelt(D_OH^Cpx/Melt)).Besides, this study got the water contents of clinopyroxene atdifferent experimental condition, which could provide some evidences to understandthe water distribution at different depth in the upper mantle.