Roiling cauldrons of liquid-laden material flow within Earth’s rocky interior. Understanding how this matter moves and changes is essential to deciphering Earth’s formation and evolution as well as the processes that create seismic activity, such as earthquakes and volcanoes. Bjørn Mysen probes this hidden environment in the laboratory and, based on his results, models can help explain what goes on in this remote realm.
Mysen investigates changes in the atomic properties of molten silicates at high pressures and temperatures that pervade the interior Earth. Silicates comprise most of the Earth's crust and mantle. He uses devices, such as the diamond anvil cell, to subject melts and fluids that form silicate rocks to the conditions of the deep Earth and uses spectroscopic technology to witness physical transformations.
The transport processes that shape the interiors of all the terrestrial planets are governed by the physical and chemical properties of silicate melts, the dominant part of magma, and certain associated water-rich fluids. Magma is formed by the partial melting of crystalline minerals. The water-rich fluids are extracted from water-laden (hydrous) minerals under high-temperature and pressure conditions. This melting and dehydration happen between 1,100˚F and 2,900˚F and at depths from several miles to hundreds of miles. At these depths, pressures range from about 2,000 to 100,000 times atmospheric pressure.
These melts and fluids are the principal agents for material and energy transfer within the Earth. Their viscosity and density contrast with those of surrounding crystalline materials, enabling them to travel through the crystalline matrix. Mysen looks at the most important properties for understanding material movement : viscosity, and the thermodynamics involved in material/energy transfer among other characteristics.
He is particularly interested in defining the conditions of melting mantle materials, how elements separate and how their isotopes—elements with different numbers of neutrons--separate between minerals, fluids, and melts at high pressures and temperatures. He also looks at the relationships between structure and properties of silicate melts and so-called COHN fluids at high temperature and high pressure and what the solubility mechanisms of fluids in silicate melts are and of silicates in aqueous fluids under conditions of the deep Earth.
Mysen received his B. Sc. and M.A. from the University of Oslo and his Ph.D. from the Pennsylvania State University. Before joining the Carnegie staff in 1977 he was a predoctoral and postdoctoral fellow. For more information see here
