Study of metallic Fe-Ni-Co alloy and stony part isolated from Seymchan meteorite using X-ray diffraction, magnetization measurement and Mössbauer spectroscopy

A detailed study of Fe-Ni-Co alloy and stony part extracted from Seymchan (main group pallasite) meteorite fragment using X-ray diffraction, magnetization measurements, and Mössbauer spectroscopy with a high velocity resolution was carried out. A complex phase composition in Fe-Ni-Co alloy was observed. The Mössbauer spectrum of this alloy was fitted using eight magnetic sextets which were related to α2-Fe(Ni, Co), α-Fe(Ni, Co) and γ-Fe(Ni, Co) phases. The stony part consists of the following iron-bearing phases: olivine, troilite, Ca-rich clinopyroxene, chromite and probably iron-magnesium chromite. Estimations of the Fe2+ partitioning between the M1 and M2 sites in olivine and Ca-rich clinopyroxene were based on X-ray diffraction and Mössbauer data. The distribution coefficients KD and the temperatures of Fe2+ and Mg2+ cations equilibrium distribution Teq in olivine were evaluated using X-ray diffraction data and Mössbauer parameters.