Towards evaluating the viscosity of the Earth's outer core: An experimental high pressure study of liquid Fe-S (8.5 wt.% S) - art. no. 1217

摘要

1] In-situ high pressure viscosity measurements, using synchrotron X-ray radiography, have been carried out on liquid Fe-S (8.5 wt.% S) at pressures up to 6 GPa and at 1823 K. Here we show that (i) the effect of pressure on the isothermal viscosity is substantial, with an apparent activation volume of 5.8 cm(3)/mol; and (ii) viscosity is constant along the pressure dependent melting boundary. Assuming the independence of viscosity along the melting boundary up to core pressures, our results yield a viscosity for the Earth's outer core, at the inner core boundary, of 1.6 x 10(-2) Pa s. On this basis, we present a revised viscosity profile across the outer core. [References: 26