Pair Distribution Function at high pressure sheds light on deep geological processes

The study of the evolution of the structure upon pressure is indispensable for the understanding of many geological processes. In particular, the structure of CaF2 and of the other compounds presenting the so-called fluorite type time-averaged structure has been widely investigated by diffraction methods. However, due to the technical difficulties to obtain suitable Pair Distribution Functions (PDF) at high pressure, the role of the local structure in the evolution of these minerals upon compression is still virtually unexplored. With the new EBS of ESRF and the setup available at ID15a, it can be now possible to study these materials with total scattering in situ as a function of the pressure. In this experiment, we will explore the local arrangement of two fluorite-type minerals (CaF2 and BaF2) tracing a link between disordered local structure and the average behavior upon compression.