Natural bridgmanite-periclase aggregates in Martian meteorites

Monday, 15 December 2014
Oliver D Tschauner, Univ Nevada, Las Vegas, NV, United States, Chi Ma, California Institute of Technology, Pasadena, CA, United States, Clemens Prescher, The University of Chicago, Argonne, IL, United States and Vitali Prakapenka, University of Chicago, Argonne, IL, United States
We use a combination of in-house- and synchrotron-based micro-mapping techniques to identify and characterize natural parageneseis of bridgmanite (MgSiO3 in the perovskite structure, IMA 2014-017) and periclase in shocked meteorites. The goal is to evaluate if shock-generated bridgmanite-melt, bridgmanite-periclase intergrowths provide information on element partitioning and rock-deformation that complement experimental studies. As in case of any natural rock recovered from high P-T conditions, chemical and physical changes during release require careful assessment. Major- and minor element concentrations are measured quantitatively with EPMA. Phase identification,-distribution, as well as internal structural parameters are evaluated based on micro-diffraction mappings. Laue diffraction peak profile analysis permits examination of dislocations active during deformation of bridgmanite-periclase aggregates.