This Early Grant for Exploratory Research (EaGER) will support a collaborative study between mineral physicists and seismologists to try a new approach of combining mineral physics and seismology to provide new perspectives of the deep Earth. Advances in seismic imaging of the Earth's deep interior, from global to local scales, are providing structural information about convective and thermal patterns in the lower mantle. Development of first principles methodologies to tackle key mineral physics problems, e.g., thermoelastic properties, spin crossover in iron in lower mantle minerals, and anharmonic thermal properties, are greatly expanding characterization of mineral properties at deep mantle conditions.
The goal and primary intellectual merit of the proposed work is to advance understanding of deep mantle structure, temperature, and composition with a transformative multidisciplinary effort to directly link seismological imaging with modeling approaches based on realistic mineral properties. The team will address an unresolved central issue in investigations of deep mantle temperature and composition: the subtle effects of spin state changes in iron in lower mantle minerals and potential seismological detection of this fundamental transition and corresponding implications for bulk chemistry of the lower mantle. Clarification of the seismic signature of spin state crossovers is a major hurdle to be overcome in mineralogical interpretations of seismological data of the deep Earth. The proposed search for spin transition signatures in the deep mantle is not without risks, but this unprecedented joint seismology/mineral-physics enterprise will pave the way for future studies of numerous fascinating structures holding keys to the nature of the deep mantle. It will open a needed first-hand dialogue between these communities and enable elasticity data to be accessible online for use by the seismology community for modeling purposes. The PIs of this study have diverse expertise that will help the team to foster a multi-disciplinary education experience at the interface between seismology and mineral physics.
