Mapping the Middle of the Mantle-Core Dynamic

Washington University, Saint Louis MO

Investigators

Abstract

The PI proposes to provide the seismological information about the lowermost mantle that will allow him to quantify how much heat is flowing out of Earth?s core and into the mantle. The flow of heat determines how a planet behaves over time. This includes driving plate tectonics, generating hotspot mantle plumes, creating earthquakes and volcanoes, and cycling water through subduction zones. Though we can measure how much heat flows out of Earth and into space (at a rate of 46 terawatts), we still do not know how much heat is generated by radioactivity within the crust and mantle and how much passes into the mantle from the core. This project will help (combined with the research of mineral physicists) to compute the heat coming out of the core, which will, as a result, also constrain how much heat is generated within the earth by radioactivity. The PI proposes to carry out an investigation of the vertical velocity structure of the base of the mantle using synthetic seismogram modeling of 30+ years of global seismic data of core-diffracted P and S waves (Pdiff, Sdiff). These investigations will allow for calculations of the total and regional heat flow rates from the core into the mantle and provide foundations for the answers to major questions about the geodynamics of the mantle, including the power for the mantle convection system, the residence time of post-subduction mantle lithosphere at the base of the mantle, the power for the core magneto-geodynamo, mantle plume generation, and the dynamic role of large low-shear-velocity provinces within the thermal boundary layer structure of the core mantle boundary region. Our work will also involve the development of educational materials and curricula through partnerships with science centers, schools, and textbook companies.