The microstructural investigation and phase diagnostics of different silica segregations from impactites of the Kara astrobleme were conducted using the methods of petrographic analysis, X-ray diffraction, infrared (IR) and Raman spectroscopy. The studied collection of siliceous isolations covers a number of impact transformations of quartz from quartz veins, which preserved their original structure, up to strongly transformed fragments of quartz and silica deposits in the postimpact hydrothermal process also. The peculiarities of quartz and other silica modifications, representing the major stages of impact metamorphism in rocks of the coptogeneous complex: planar cracks, planar deformation elements, coesite, newly formed and crystallized diaplectic glasses, crystallized glass of melting postimpact chalcedony and cristobalite-tridymite allocations were revealed. Coesite and diaplectic quartz glass are in the paragenetic association, which was preserved in its primary state in the siliceous lithoclasts of suevites. The textural characteristics and data of structure-phase diagnostics of silica from the impactites can be used as standards to identify similar formations located outside the modern boundaries of the impact structure.
It is established that the meteorite Chelyabinsk LL refers to a group of low-iron olivine ordinary chondrites. The mineral composition of the meteorite is defined moderate-ferrous olivine (Fa24-36), iron-magnesium and calcium pyroxene, anorthoclase, high-chromium Cr-spinels, monosulfide series geksapirrotin-troilite-makkinavit, pentlandite, samorodnometallicheskimi phases (nickel-iron, iron-nikelil, copper), apatite, dolomite hibbingitom. In thermogenic rims installed presumably enstatite glass with inclusions of magnetite. Content was determined in the debris of the meteorite and its carbon isotopic composition.
The article presents the results of mineralogical and crystal-chemical studies ferriferous types Timan bauxite. The peculiarities of the distribution of Fe2+ and Fe3+ in the structural positions in oxides, oxyhydroxides, and phyllosilicates was discussed. These data are important for improving the technology of processing natural aluminum raw material.
