This project focuses on slab mass transport into the lower mantle. It will, 1), expand the range of constraints on the degree of slab stagnation, e.g. by detailed analysis of transition zone thickness as well as hypothesis-driven reinversion of seismological data; 2), construct, by means of further software development, regional dynamic models and simplified global parameterizations for stagnation systematics in a thermo-chemical, multi-phase transition mantle system; and, 3), benchmark these computational convection models for vertical and horizontal transport. A graduate student from an under-represented group will be trained in interdisciplinary research. All project software will be developed openly and shared freely online. The tomographic inversion and modeling tools will be implemented into the Solid Earth Teaching and Research Environment software framework, allowing data-driven hypothesis testing for entirely different geodynamic questions and facilitating the training of Earth science students in interdisciplinary research.
Better estimates of the slab flux, over time and with error bars, will help to constrain geochemical mixing and thermal Earth evolution models. The study will contribute to the use of slabs for absolute plate-tectonic reference frames, and slab dynamics has other, broad implications such as on net rotations of the lithosphere with respect to the lower mantle, interactions with the super-continental cycle, and sealevel variations.
