UDC 552.63+523.681.2
Features of mineral and geochemical composition of Chelyabinsk meteorite
S. V. Berzin, Yu. V. Erokhin, K. S. Ivanov, V. V. Khiller
A meteorite is a chondrite and belongs to petrological type LL5. Meteorite fragments have higher contents of Na, U, Ag and lower contents of Cr, Mn, Ni, Zn, and Cs compared with an average of ordinary chondrites. The meteorite is composed of olivine, orthopyroxene, clinopyroxene, plagioclase, chromite, metals of iron and nickel, sulfides, Cl-apatite and glass, which has feldspar composition. During high-temperature recrystallization of the meteorite matrix, sulfide and Fe, Ni-metals are segregated in linear zones, interleaved with silicate areas. In black meteorite fragments, shock veins and sulfide micro-branching veins, formed by the effects of three stages of impact, accompanied by full or partial melting of meteoritic material, are observed. In fragments of gray chondrite, one stage of impact is observed giving rise to the formation of black veins. Pores are formed by accretion of solid fragments of the meteorite account for 2–3% of chondrites. Plagioclase, clinopyroxene and olivine, located freely in the pores, have complete crystalline facets. They were captured in the pores during their formation and indicate that undifferentiated formations, which later became the chondrules, and minerals that are the products of the differentiation of silicate substances, were in the parental environment of chondrites.
Keywords: Ural; Chelyabinsk meteorite; chondrite; mineralogy; geochemistry; shock veins; sulfide micro veins; porous space.
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