Using Multigrain Crystallography to Explore the Microstructural Evolution of the α-Olivine to γ-Ringwoodite Transformation and ε-Mg2SiO4 at High Pressure and Temperature

The introduction of multigrain crystallography (MGC) applied in a laser-heated diamond anvil cell (LH-DAC) using synchrotron X-rays has provided new path to investigate the microstructural evolution materials at extreme conditions, allowing for simultaneous investigations phase identification, strain state determination, and orientation relations across transitions single experiment. Here, we this method sample San Carlos olivine beginning ambient conditions through α-olivine → γ-ringwoodite transition. At temperatures, by measuring individual Bragg reflections, shows profuse angular streaking consistent with onset yielding measured stress ~1.5 GPa, considerably lower than previously reported, which may have implications mantle evolution. Furthermore, was found nucleate as micron sub-micron grains imbedded small amounts secondary 15 GPa 1000 °C. Using MGC, were able extract refine crystallites unknown where it structure ε-phase described chondritic meteorites.