Keywords:magma, viscosity, high pressure, mantle, synchrotron radiation
Viscosity is a fundamental property controlling the transportation of magma in the planetary interiors. In this study, we measured the viscosity of KAlSi3O8 composition of melt under high pressure. The viscosity was measured by the falling sphere method using an X-ray radiography system. Experiments were performed at the NE7A station of the PF-AR synchrotron radiation facility in KEK, Tsukuba, Japan. High pressure was generated using a Kawai-type apparatus driven by a DIA-type guide block in the MAX-III press. A powder of natural sanidine (KAlSi3O8) was loaded with a platinum sphere in a molybdenum container. Powder X-ray diffraction data were obtained by energy-dispersive method using an pure Ge solid state detector. Pressures were determined by using an equation of state of MgO. The results show that the viscosity of KAlSi3O8 melt decreased with increasing pressure up to 6 GPa.