Melting and melt properties

Melt has much higher element diffusivity and is much more mobile. Melts should play vital roles in geochemical processes in the Earth's interior. Melt properties are, however, difficult to investigate by high P-T experiments due to the following reasons.

  1. Melting points of mantle materials such as peridotite and basalt are extremely high.
  2. Mantle melts cannot be recovered to ambient conditions. Although a number of high-pressure minerals can be recovered to ambient conditions, melts structures should be changed during recovery. In many cases, especially at high pressures, melt cannot be quenched even to glasses.
  3. Melts tend to migrate in sample chambers due to the steep temperature gradients produced by tiny furnace in high-pressure cells.

In order to overcome these problems, we have developed the following technologies.

  1. Temperatures up to 3000 K can be routinely generated using newly developed CVD-synthesized boron-doped diamond heaters [Xie et al., 2020; Nishida et al., 2020].
  2. Conditions of melt quenching have been expanded by increase of cooling rates [Bondar et al., 2020].
  3. Uniform temperature fields are produced by a new furnace geometry [Zarei et al., 2018].

We are investigating melting relations, element partitioning and melt (quenched glass) structures by using these technologies.

Experimental techniques