Characterization of Northwest Africa 6286 and 7857 ordinary chondrites using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy
A.A. Maksimova, M.I. Oshtrakh, A.V. Chukin, I. Felner, G.A. Yakovlev, V.A. Semionkin
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 192, 5 March 2018, Pages 275-284
“Highlights
• The main and minor iron bearing phases in NWA 6286 and NWA 7857 meteorites
• Determination of the 57Fe hyperfine parameters for the iron bearing phases
• Determination of Fe2+ partitioning between the M1 and M2 sites in silicate phases”
“Northwest Africa (NWA) 6286 and 7857 meteorites were studied in detail by using optical microscopy, scanning electron microscopy with energy dispersion spectroscopy, X-ray diffraction, magnetization measurements and 57Fe Mössbauer spectroscopy with a high velocity resolution. The main and the minor iron-bearing phases were identified in both meteorites. The unit cell parameters as well as Fe2+ and Mg2+ cation distribution were determined for the M1 and M2 sites in silicate microcrystals. Saturation magnetic moments were obtained for both meteorites. Mössbauer parameters for the main and the minor iron-bearing microcrystals were estimated and compared for NWA 6286 and NWA 7857 LL6 ordinary chondrites. The Fe2+ and Mg2+ cation partitioning, distribution coefficient and temperature of cation equilibrium distribution were estimated for silicate microcrystals using X-ray diffraction and Mössbauer spectroscopy.”
