2025/10/24 by Keiya Ishimori, Shintaro Azuma, Kentaro Uesugi +6
Earth and Planetary Sciences · #Geological and Geochemical Analysis #High-pressure geophysics and materials #earthquake and tectonic studies
paper · doi:10.1016/j.pepi.2025.107461
openalex publication_date 2025/10/24 · openalex created_date 2025/10/25 · openalex updated_date 2026/07/28
MgO is the end-member of the primary constituents of the lower mantle, and identifying its crystal preferred orientation (CPO) developments or slip systems is key to understanding seismic observations and the dynamics of the lower mantle. To investigate the temperature dependence on CPO developments in MgO under high-pressure conditions corresponding to the lower mantle, we conducted large-strain deformation experiments using the rotational diamond anvil cell (rDAC) combined with synchrotron X-rays, achieving pressures up to 80 GPa and temperatures up to 973 K. Our results revealed that the CPO developments in MgO under large-strain deformation are temperature-dependent even at relatively low temperatures. The crystal plane parallel to the shear plane changed from the 110 plane to the 100 plane with increasing temperature and pressure. Based on our experimental results, we constructed a temperature-pressure map that shows the CPO variation of MgO. The temperature-pressure map obtained in this study provides essential foundational information for advancing our understanding of rheology in the lower mantle.