GENERATION OF NICKEL-IRON CRYSTALS IN THE KAIDUN METEORITE. THE ROLE OF CARBONYL COMPOUNDS

Abstract

The Kaidun meteorite is a highly heterogeneous polymict breccia with a unique set of components, namely, various types of carbonaceous and enstatite chondrites. This unusual association strongly implies unusual processes in the parent body. Morphologic investigation of the groundmass on the surface of a chip formed during the fall of the meteorite found a geode about 2 mm in diameter filled with isometric or elongated black crystals measuring up to 0.35 mm in length. The crystals adhered weakly to each other and to the wall of the geode, and most had been lost before the specimen was received by the USSR Academy of Sciences. The crystals were subjected to X-ray structural analysis in oscillating crystal and Gondolfi camera, and to microprobe analysis, and were examined under the scanning electron microscope. We suggest a model for the generation of nickel-iron crystals in the Kaidun meteorite.