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   T 44


    The epithermal gold-telluride Kochbulak deposit (Uzbekistan) [Text] / V. A. Kovalenker, Yu. G. Safonov, V. B. Naumov, V. L. Rusinov // Geology of Ore Deposits. - 1997. - Vol. 39, № 2. - P107-128. - Bibliogr. : p. 128 (42 ref.)

ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
DEPOSIT -- EPITHERMAL GOLD-TELLURIDE KOCHBULAK DEPOSIT -- KOCHBULAK DEPOSIT -- VOLCANIC SEQUENCE -- PORPHYRY DIKES
Аннотация: The Paleozoic epithermal gold-telluride Kochbulak deposit is situated on the northern slope of the Kurama Range in the central Tien Shan (Uzbekistan). The deposit is located within an andesite-dacite volcanic sequence (C2-3) intruded by subalkaline granodiorite and granosyenite porphyry dikes (C3-P1). The ore-forming system of the deposit originated and evolved during the orogenic uplift associated with aerial volcanism and emplacement of porphyritic granitoids. The Kochbulak deposit contains a great diversity of ore-forming sulfides, sulphosalts, tellurides, and selenides, several of which were first found there. The deposit has features of epithermal mineralization of both the adularia-sericite and acid-sulfate genetic types and mesothermal gold mineralization. The deposit consists of high- and low-angle veins and ore-bearing breccia pipes. The pipe-shaped bodies and veins differ in ore, gangue, and metasomatic mineral assemblages. The ore bodies hosted by explosive-hydrothermal breccias contain goldfieldite, famatinite, luzonite, enargite, diaspore, and pyrophyllite and, therefore, have pronounced features of epithermal mineralization of the acid-sulfate type. The ore veins show evidence of deeper formation and are associated with quartz-carbonate-sericite wall rock alteration. Our study of mineral assemblages, fluid inclusions, sulfur, oxygen, and hydrogen isotopes, and thermodynamic calculations show that the Kochbulak deposit was formed during a cyclic multistage process with periodic alternation of sealing along with tectonic and explosive opening of the fluid channel ways. The ore-forming process is subdivided into the preore, I to III ore, and postore stages related to fracture opening. Three types of solutions took part in the formation of gold-sulfide-sulphosalt-telluride mineralization. They were distinct in temperature, composition, salinity, and proportion of meteoric and magmatic water and other volatile components. The temperature generally decreased from 465°C to <100°C, and slightly increased at the beginning of each stage of the ore-forming process. Pressure, salinity, ion and gas composition of solutions, and the oxygen isotope composition of water varied as well. The deposition of gold-productive mineral assemblages was caused by changes in pH, Eh, activities of S2, O2, and Te2. The recurrence of these changes and repeated mineral deposition within the same depth intervals formed bodies very rich in ore components. The above-mentioned data suggest the Kochbulak deposit represents a particular type of gold-telluride mineralization, which originated within a wide range of physicochemical conditions at hypabyssal to subsurface depths.????

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   R 95

    Rusinova, O. V.
    Metasomatism in the Muruntau ore field (Western Uzbekistan) [Text] / O. V. Rusinova, V. L. Rusinov // Geology of Ore Deposits. - 2003. - Vol. 45, № 1. - P66-85. - Bibliogr. : p. 85 (34 ref.)

ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
GOLD -- METALLOGENESIS -- METASOMATISM -- MINERALIZATION -- ORE DEPOSIT
Аннотация: The formation of the giant Muruntau gold-quartz deposit and ore field (western Uzbekistan) is defined as a prolonged (70 Ma) multiphase geological process related to shear tension and ductile deformations of rocks. The history of the ore field development is very complicated, and there is still much to be learned about it. We studied the conditions, zonation, and deformations of the metasomatism-related ore formation, as well as the behavior of carbonaceous matter (CM) in this process. Lower Paleozoic sheared carbonaceous host rocks are regionally metamorphosed in the muscovite-chlorite subfacies. This process, which evolved over a long time (C3-P1), started with the increase in temperature (the progressive megastage) and continued during its decrease when the bulk of gold was deposited. The beginning of the process was associated with ductile deformations that showed up in folding and shearing of rocks. At that time, pre-ore magnesium-potassium metasomatism took place in the temperature interval of 400-600°C. During the regressive megastage, calcium metasomatism occurred and skarn assemblages (actinolite, clinozoisite, diopside, and garnet) were deposited at T = 400-520°C. Later, ductile deformations were replaced by brittle deformations, and quartz-ore veinlets and lenses formed together with locally developed vein-related orthoclase-chlorite, albite-carbonate, sericite-tourmaline, and quartz-adular metasomatites. The metasomatic zonation showed up at early stages and was oriented along the direction of fluid filtration. The outer (front) zone is represented by a dome of biotitized rocks. Banded biotite-feldspar-quartz metasomatites occur within them. Their back (inner) zones are composed of the biotite-orthoclase-quartz assemblage. Younger skarn assemblages make up series of thin bands within biotite-feldspar-quartz metasomatites. Ore veinlets are enclosed within this metasomatic halo. CM took an active part in the hydrothermal process: it was output from metasomatic zones and redeposited along their outer boundary. CM interacted with the hydrothermal solution and maintained the reducing medium at the level of a QFM buffer. Temperatures established by the carbon isotope thermometer (CM + carbonate) are similar to values of mineral geothermometers (250-350°C during ore deposition). The distinctive features of metasomatism in the Muruntau ore field, hosted by carbonaceous sequences and shear zones, are the absence of vein-related zonation and a poor vertical zonation (a low T gradient), suppressed acid metasomatism, and the lack of an obvious relationship between ore mineralization and a particular magmatism.????

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   F 33


    Features of silicon- and titanium-polyethylene glycol precursors in sol-gel synthesis of new hydrogels [Electronic resource] / T. G. Khonina, A. P. Safronov, M. V. Ivanenko, E. V. Shadrina, O. N. Chupakhin // Journal of Materials Chemistry B. - 2015. - Vol. 3, № 27. - С. 5490-5500. - Bibliogr. : p. 5499-5500 (38 ref.)

ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
MODIFIED SILANES -- MINERALIZATION -- MONOLITHS
Аннотация: The formation of organic/inorganic hydrogels based on silicon and titanium polyethylene glycolates, new biocompatible water-soluble precursors in sol-gel processing, was investigated. The influence of different factors on the gelation process, such as excess of PEG, water molar content, pH of medium, electrolyte additives, was investigated in comparison with silicon-and titanium-glycerol precursors. The specific features of gelation for each type of precursor were revealed. It has been determined that titanium polyethylene glycolates synthesized and used in the excess of PEG formed transparent polymeric hydrogels resistant to syneresis under certain conditions. The titanium polyethylene glycolates synthesized without excess of PEG formed turbid heterogeneous colloidal gels. In the case of silicon polyethylene glycolates the hydrogels obtained were polymeric. Dynamic light scattering was used to confirm the polymeric or colloidal type of gelation. The solid and liquid phases of polymeric silicon- and titanium-polyethylene glycol hydrogels were separated by exhaustive extraction. The solid phase was characterized by combined thermal analysis with simultaneous quadruple mass spectrometry, XRD, IR spectroscopy, and liquid phase-atomic emission spectroscopy. The structural features of polymeric gels were investigated by SEM and TEM methods. The cross-linking density of polymeric hydrogels was evaluated using Flory-Rehner theory based on the mechanical properties of swollen networks of flexible polymeric chains

\\\\expert2\\nbo\\Journal of Materials Chemistry B\\2015. V. 3, N 27. P. 5490-5500.pdf
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