Kafiosite turned out to be a product of metamorphosis
A new mineral – kafiosite – was discovered at the Institute of Geochemistry and Analytical Chemistry named after. Vernadsky RAS. In the first days of the new year, 2024, it was registered with the International Mineralogical Society. The history of the meteorite and the kafiosite “MK” found in it was told by Marina Ivanova, the leading researcher at the Geochemical Institute of the Russian Academy of Sciences, Doctor of Geological and Mineralogical Sciences, who discovered it.
Dhofar 225 meteorite. Photo courtesy of GEOKHI RAS.
First, about the meteorite itself. He was found on January 15, 2001 in the Dhofar region of Oman. The black stone weighing 90 grams turned out to be a carbonaceous chondrite with a distinct melting crust. It turned out to be rich in calcium, aluminum, olivine aggregates and rare chondrules – small spheres with a diameter of about 1 millimeter, which are found only in stony meteorites of the chondrite type.
– Let's start with the fact that the meteorite itself turned out to be a rather rare type, – says Marina Alexandrovna. – It belongs to the group of carbonaceous meteorites of the SM type that have undergone metamorphism. In other words, the parent body – the asteroid from which a fragment once broke off has experienced external influences that have changed its composition. We can now say with complete confidence that this asteroid was dehydrated as a result of strong heating, either when passing near the Sun, or during impact processes.
– Collectors from Russia shared with us who go on expeditions and look for meteorites in the desert.
– About 20 grams. The sample was brought and transferred to the meteorology laboratory of GEOKHI, a section was made from it and the chemical composition of the minerals began to be determined. We sent a separate sample to study the isotopic composition of oxygen in this meteorite. According to many characteristics, Dhofar 225 can be combined with several previously found meteorites, but the mineral we named kafiosite, has never been found anywhere before, – neither in cosmic bodies, nor on Earth.
– The mineral kafiosite, named by us after the main elements CaFeOS, – not primary, it is a product of change, metamorphism, which occurred on the asteroid during its celestial journey. From it we can judge what processes occurred on the asteroid earlier: how close it came to the Sun, how long the heating took, what reactions there were.
– The work is still underway, but we can already assume that the temperature at which the mineral was formed was more than 800 degrees Celsius. It probably formed due to the heating of carbonates that were originally in the meteorite. These carbonates, having decomposed, reacted with iron and sulfur from another mineral (which was also no longer left). In general, the components of this decomposition combined together and formed a new mineral.
– Perhaps in the future we will find a use for it. But this will happen only when the asteroids themselves become available to us – parent bodies of meteorites from which minerals can be obtained. In the meantime, the new mineral requires additional study; first of all, it is of interest specifically for fundamental science.
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