Abstract—The regions of localized shock melting (melt pockets) in one of silicate inclusions in IIE Elga iron meteorite were investigated with EMPA, SEM, TEM and Raman spectroscopy. It has been established that the mechanism of formation of melt pockets in Elga is of a mixed nature, being associated not only with melting in situ of the silicate matrix, but also with the intrusion of portions of the melted schreibersite–oxide rim into the silicate inclusion. Melt pockets have an emulsion texture, which is a sign of phase separation by liquid immiscibility in high-temperature shock melts. The emulsion texture formed by droplet-shaped exsolutions of siderite in the schreibersite matrix of one of the melt pockets has all the features of phase separation by liquid immiscibility at superliquidus temperatures. This convincingly indicates the extraterrestrial origin of siderite in the Elga meteorite.
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Impact resistance (impedance) is a shock wave velocity multiplied by the density.
FeO* means that the valent state of iron in oxide was not determined.
Element composition is given in at %.
Temperature of SiO2 melting at normal pressure of 1710°С.
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We are grateful to A. Burmistrov and E. A. Pankrushina for help in the performance of SEM and Raman spectroscopic studies. K. A. Lorenz is thanked for constructive review.
The work is partially supported by the Presidium of the Russian Academy of Sciences (program no. 28).
Translated by M. Bogina
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Khisina, N.R., Wirth, R. & Abdrakhimov, A.M. Liquid Immiscibility in Regions of Localized Shock-Induced Melting in the Elga Meteorite. Geochem. Int. 57, 903–911 (2019). https://doi.org/10.1134/S0016702919080068
- IIE iron meteorites
- melt pockets
- shock melting
- liquid immiscibility
- meteorite Elga