Seminar: Deep mantle deformation and microstructures from high pressure mineral physics experiments
E001
Abstract
Microstructures record the effect of dynamical processes on mineral and rocks and can be used to unravel the history and geodynamical contexts of various regions of the Earth. In this work, we focus on the deep Earth mantle and study the connection between mantle convection, high pressure microstructures, and seismic observations. To do so, we apply high pressure and high temperature deformation to samples relevant for deep Earth processes, such as olivine and its high pressure polymorphs wadsleyite and ringwoodite, or pyrolic assemblages, which are representative of a mean mantle composition. High pressure materials can not be studied post-mortem using more conventional methods such as EBSD. We hence study the effect of phase transformations and deformation on microstructures in-situ, using advanced techniques such as multigrain crystallography in the laser-heated diamond anvil cell. Finally, the results are integrated into mantle convection models and compared to seismic observations. Here, I will show examples of this work, with applications to subduction in the Earth’s lower mantle and how plastic deformation of rocks and minerals can be used to understand observations such as the elusive 1000 km discontinuity in the Earth’s mantle.