Fate of Slabs and Stirring – Magali’s Lecture at CIDER, 2018

The fate of slabs as they sink into the upper most lower mantle is a important question for understanding the history of our planet. Do slabs actually make it to the core-mantle-boundary? How can we interpret the fast seismic anomalies that we see in seismic tomography images?Can we make geologic-type reconstructions of slabs linking seismic tomography images to models of plate motions in time? This  CIDER 2018 lecture provides an overview of observations, the basic physical principles that govern the dynamics of slabs as they sink through the upper mantle and into the lower mantle, and presents example cases that illustrate how slabs interact with changing viscosity structure and upwellings in the lower mantle. A major take-away from the examples is that the present-day geometry of a slab does not necessarily tell you the path the slab took to reach that point (a basic principle from structure geology… there are multiple strain path to reach a final state of deformation).   A PDF of the talk can be found on the CIDER wiki page as well as a video of the actual lecture.