The viscosity and thermal conductivity of diopside under extreme conditions

The explorations of heat transport properties of minerals under extreme conditions are critical for understanding the formation and evolutionary processes of the Earth. Here, we perform systematic study on viscosities and thermal conductivities of diopside with different calcium contents under high temperature and high pressure through molecular dynamics simulations. The results demonstrate that both viscosities and thermal conductivities of diopside increase with rising pressure and decrease with increasing temperature. The effects of calcium content on the transport properties of diopside are distinct. Higher calcium content leads to the increase of viscosity and the reduction of thermal conductivity under extreme conditions. These behaviors are attributed to the larger ionic radii of Ca²⁺ions compared to other cations in diopside, which result in compressed local structures and enhanced interatomic interactions. These findings provide valuable insights into the transport properties, energy transformations, and lithospheric dynamics of silicate minerals under extreme conditions, and offer a deeper understanding of geophysical processes within Earth's interior.