DISTRIBUTION AND SEGREGATION OF TRACE ELEMENTS DURING THE GROWTH OF ORE MINERAL CRYSTALS IN HYDROTHERMAL SYSTEMS: GEOCHEMICAL AND MINERALOGICAL IMPLICATIONS
V.L. Tauson1, S.V. Lipko1, N.V. Smagunov1, R.G. Kravtsova1, K.Yu. Arsent’ev2
1A.P. Vinogradov Institute of Geochemistry, Siberian Branch of Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia
2Limnological Institute, Siberian Branch of Russian Academy of Sciences, ul. Ulan-Batorskaya 3, Irkutsk, 664033, Russia
Keywords: Рост кристалла, микроэлементы, поверхность, распределение элементов, сегрегация, микровключения, наночастицы, агрегация, благородные металлы, структурные примеси, поверхностно-связанные примеси, Crystal growth, trace elements, surface, element distribution, segregation, microinclusions, aggregation, noble metals, structural impurities, surface-bound impurities
Abstract
The interfacial crystal layer of poorly soluble mineral grown under hydrothermal conditions is modified chemically into a surficial nonautonomous phase (SNAP) and, in this capacity, takes part in growth process, doing several important functions. This paper considers some of them related to geochemistry and mineralogy. The new interpretation is given to the following phenomena: (1) selection of components during crystal growth in multiphase associations; (2) stability of multiphase parageneses having a common chemical component; (3) dual character of the distribution coefficients due to different properties of the crystal volume and SNAP; (4) formation of nano- and microinclusions of unusual composition different from the basic mineral phase; (5) spatial ordering of nano- and microparticles during their directed aggregation at the growing crystal face; (6) accumulation of valuable components (primarily noble metals), incompatible in most of mineral matrixes, in the surficial layer; and (7) effect of “hidden” metal content, associated with the presence of noble metals in the SNAP or of nano- and microinclusions formed during the SNAP evolution.
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