¹Chi Ma,²Oliver Tschauner,¹John R. Beckett,³Vitali B. Prakapenka
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14302]
¹Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
²Department of Geoscience, University of Nevada, Las Vegas, Nevada, USA
³Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois, USA
Published by arrangement with John Wiley & Sons

High-pressure oxides like perovskite-type FeTiO3, CaTi2O4-type Fe2TiO4, and ferrous-ferric oxides that form polysomes between wüstite and CaFe2O4-type Fe3O4 are potential carriers of Fe, Ti, and other transition metals in the mantle and may play an important role in the redox budget of the deep Earth. Here, we report the occurrence of three of these phases as the new minerals: feiite (Sr2Tl2O5-type Fe2+2(Fe2+Ti4+)O5), liuite (FeTiO3 with a GdFeO3-type perovskite structure), and tschaunerite (CaTi2O4-type (Fe2+)(Fe2+Ti4+)O4), along with wangdaodeite (LiNbO3-type FeTiO3) in a transformed ulvöspinel clast entrained in a shock melt pocket in the Shergotty Martian meteorite. We show that reaction between the shocked ulvöspinel precursor and melt occurred at pressures between 20 and 25 GPa. The high-pressure Fe-, Ti-minerals lost Fe and O to the surrounding shock melt in exchange for Si, Mg, and Ca. Concentrations of Si and Mg in all of these clast phases and of Na in liuite are significant. They substantiate chemical interaction of the clast with melt during the shock event and highlight potential elemental distributions in complex Fe- and Ti-rich lithologies at pressures of the deep transition zone to shallow lower mantle.