Discovery of Panguite, a New Ultra-Refractory Titania Mineral in Allende

摘要

During our nano-mineralogy investigationudof the Allende meteorite, we identified a newudtitania mineral named “panguite” in an ultra-refractoryudinclusion within an amoeboid olivine aggregateud(AOA). It has an orthorhombic Pbca structure relatedudto the Ia3 bixbyite type and a formula unitud(Ti^(4+),Al,Sc,Mg,Zr,Ca,□)_2O_3. We used electron probeudmicroanalysis (EPMA), high-resolution scanning electronudmicroscope (SEM), electron backscatter diffractionud(EBSD), synchrotron micro-Laue diffraction withudsubsequent energy scans, and micro-Raman analysesudto characterize the composition and structure. Panguiteudis not only a new mineral but also a new phase as syntheticudIa3 (Ti^(4+),Al,Sc,Mg,Zr,Ca,□)_2O_3 is not known.udWe report here the type occurrence of this new titaniaudin nature and discuss implications of this phase forudprocesses very early in the history of our solar system.udThe mineral and the mineral name (panguite) haveudbeen approved by the Commission on New Minerals,udNomenclature and Classification of the InternationaludMineralogical Association (IMA 2010-057).ud