The Borodino Meteorite: Evolution on the Parent Body
K. G. Sukhanova, A. B. Kuznetsov & S. G. Skublov
Doklady Earth Sciences, Published: 18 March 2024
“The work reports on the results of the mineralogical and petrographic study of the Borodino meteorite (H5). For the first time, meteorite minerals were described and their chemical compositions were given. The following were found in the Borodino meteorite: olivine (Fa 18.16 ± 1.15), Ca-poor pyroxene – (clino)enstatite (En 81.37 ± 1.73, Wo 1.18 ± 0.31), Ca-rich pyroxene – augite (En 57.23 ± 1.57, Wo 39.38 ± 2.68), diopside (En 51, Wo 45), pigeonite (En 69, Wo 6), plagioclases – oligoclase (An 12.16 ± 1.24, Or 5.68 ± 2.12), andesine (An 48.23 ± 1.84, Or 1.23 ± 0.12), anorthoclase (An 0, Or 36) and sanidine (An 0, Or 40.00 ± 1.1), and poorly crystallized glasses of the feldspathic composition, merrillite and chromespinelide. The obtained data made it possible to estimate a degree of terrestrial weathering of the meteorite as W0 and the stage of impact metamorphism (S1-2), which suggests good preservation of the meteorite material. The composition of olivine and Cr-spinel, determined by the Electron Probe Microanalysis, was used to estimate the peak temperature of thermal metamorphism at 720°C, which falls within the temperature range (670–740°C) typical of chondrites of a petrological type 5. The presence of Ca-rich pyroxenes, large grains of Ca–Na–Mg phosphates and chromite-pigeonite aggregates in the meteorite matrix indicate the prolonged heating of the material.”
