Grant: Discovery Grants Program - Individual

The objective of my research is to improve our abilities to understand the deep interior dynamics and evolution of Earth and other planets. The dynamics and evolution of Earth's and planetary interiors will influence the outermost features of the Earth and other planets. However, their interiors are inaccessible and cannot be directly investigated. Alternative approaches are to study Earth and planetary materials at simulated environments that are similar to Earth and planetary interiors. Importantly, behavior of materials at ambient conditions (1 atm and 25 C) is different from what they exhibit at greater depths. Therefore, only those data collected at pressure (P) and temperature (T) conditions corresponding to the certain depths are valid for modeling the structure and dynamics of the Earth's and planetary interiors. Therefore, study of Earth and planetary materials at P-T conditions corresponding to their deep interiors provide a promising approach to understand the dynamics and evolution of Earth's and planetary interiors. My research program uses a diamond-anvil cell (DAC, able to generate P to 3,000,000 atm) together with resistive and laser heating methods (able to heat the sample to 300-4000 K), to study planetary materials under extreme P-T conditions. The extensive P-T ranges (1-3,000,000 atm and 300-4000K) allow us to replicate the conditions found within the Earth and planetary interiors. Moreover, using a custom-built micro-Raman system and synchrotron X-ray spectroscopy, the spectroscopic properties of relevant materials are also examined. In this proposal, we synthesize the important deep mantle and core phases (e.g. N-bearing silicates and iron nitrides, chromite spinels, reidite and ZrO2) and characterize them using synchrotron x-ray diffraction, x-ray spectroscopy, and Raman to understand their structures and physical properties (e.g. density, volume, elasticity, thermal conductivity, strength, sound velocity). The synthesized samples when quenched to ambient conditions will be examined by electron probe microanalysis and scanning electron microscopy for understanding the partitioning of the elements and element distributions within the samples, the melting criteria of the iron nitrides, and the crystal structures of the nano-scale phases. Our goals are (1) to evaluate the storage and budget of nitrogen inside the planetary interiors for future planet explorations, (2) to  evaluate the chromite spinel polymorphs at high P-T conditions and its connection to the shocked meteorites, (3) to study thermal conductivity of popular planetary phases (H2, H2O, He, N2) that can be applied to modeling the dynamics of the planetary interiors, and (4) to study the strength, deformation and texture of reidite and ZrO2 and their implications to shock history. HQP will be trained in an open, fair, diverse, vibrant and inclusive environment with transferable skills to prepare them for employment in academic, government and private sectors.