BURNETTITE, CaVAlSiO6, AND PAQUEITE, Ca3TiSi2(Al2Ti)O14, TWO NEW MINERALS FROM ALLENDE: CLUES TO THE EVOLUTION OF A V-RICH Ca-Al-RICH INCLUSION

Introduction: During a nanomineralogy investigation of the Allende CV3 meteorite, we discovered two new minerals, burnettite (IMA 2013054; CaVAlSiO6) and paqueite (IMA 2013-053; Ca3TiSi2(Al2Ti)O14), in a V-rich, fluffy Type A Ca-Alrich inclusion (CAI) A-WP1 (0.6 × 1 mm in size) in USNM 7617, which was previously studied by Paque and coworkers [1-3]. Electron probe microanalysis (EPMA), scanning electron microscopy, and electron backscatter diffraction (EBSD) were used to characterize their chemical compositions and structures. Burnettite is a V-clinopyroxene and a new member of the diopside group. It has not been previously observed in nature. Paqueite is a new Tirich silicate mineral. A similar Ti-rich phase was characterized by SEM and EPMA in CAIs from the C2 Essebi and CV3 Allende chondrites [4-6]. Both Ca(V,Al)AlSiO6 and Ca3TiSi2(Al,Si,Ti)3O14 are known as synthetic phases [e.g., 6-8]. Here, we describe burnettite and paqueite and consider their origin. Burnettite is named in honor of Donald S. Burnett and paqueite in honor of Julie M. Paque. Both are cosmochemists at the California Institute of Technology. The two new minerals and names have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association [9]. Occurrence, chemistry, and crystallography: Both burnettite and paqueite occur as micron-sized euhedral crystals within aluminous melilite (Ak9 and Ak11, respectively) in A-WP1 (Figs. 1-3). The inclusion also contains primary spinel, perovskite,