Discovery of Cl-Bearing Mayenite, Ca_(12)Al_(14)O_(32)Cl_2, a new Mineral in a CV3 Meteorite

Abstract

A unique dmitryivanovite (CaAl_2O_4) -dominant Ca-, Al-rich refractory inclusion (CAI), named "Cracked Egg" by [1], was observed in the NWA 1934 CV3 carbonaceous chondrite. During our nano-mineralogy investigation of this CAI, Cl-bearing mayenite, Ca_(12)Al_(14)O_(32)Cl_2, was identified. Electron-microprobe, SEM, electron backscatter diffraction (EBSD), and micro-Raman analyses have been used to characterize its composition and structure. Pyrometamorphic and natural Cl-bearing mayenites have been reported [2, 3] and synthetic Ca_(12)Al_(14)O_(32)Cl_2 is well known [4]. Here, we report the first occurrence of Ca_(12)Al_(14)O_(32)Cl_2 in a meteorite as a new alteration mineral in a CAI.

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