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

摘要

A unique dmitryivanovite (CaAl_2O_4) -dominant Ca-,udAl-rich refractory inclusion (CAI), named “Cracked Egg” by [1], wasudobserved in the NWA 1934 CV3 carbonaceous chondrite. During ourudnano-mineralogy investigation of this CAI, Cl-bearing mayenite,udCa_(12)Al_(14)O_(32)Cl_2, was identified. Electron-microprobe, SEM, electron backscatteruddiffraction (EBSD), and micro-Raman analyses have been used toudcharacterize its composition and structure. Pyrometamorphic and naturaludCl-bearing mayenites have been reported [2, 3] and syntheticudCa_(12)Al_(14)O_(32)Cl_2 is well known [4]. Here, we report the first occurrence ofudCa_(12)Al_(14)O_(32)Cl_2 in a meteorite as a new alteration mineral in a CAI.ud