Hydrothermal preparation of analogous matrix minerals of CM carbonaceous chondrites from metal alloy particles

A mineral assemblage that is analogous to the matrix minerals of CM carbonaceous chondrites was produced from an alloyed metal particle mixture of Fe, Mg, Al, Si, and Ni in reducing, basic and S2-containing hydrothermal environments. The elemental ratios of the alloyed metal particle mixture were adopted from reported matrix composition of the carbonaceous chondrite Murchison. The characteristic minerals of the synthetic mineral assemblage are cronstedtite, tochilinite and tochilinite–cronstedtite-intergrowth, other minerals include polyhedral serpentine, chrysotile-like phase, nanotube-like hollow structures, lizardite-like phase, brucite-like phase, etc. (not every mineral appears in a single sample, however, cronstedtite and tochilinite are two invariant minerals in the synthetic mineral assemblage). The dominant individual minerals in the synthetic mineral assemblage have remarkable similarity to the corresponding minerals of the matrix of CM carbonaceous chondrites in composition, morphology, structure, and crystallinity. Our experimental work indicates that matrix minerals of CM carbonaceous chondrites formed billions of years ago may be reproduced under laboratory conditions.