Инд. авторы:	Vasilenko V.B., Kuznetsova L.G., Tolstov A.V., Minin V.A.
Заглавие:	Evaluating the diamondiferous potential of unaltered kimberlites by the population models of their composition
Библ. ссылка:	Vasilenko V.B., Kuznetsova L.G., Tolstov A.V., Minin V.A. Evaluating the diamondiferous potential of unaltered kimberlites by the population models of their composition // Geochemistry International. - 2012. - Vol.50. - Iss. 12. - P.988-1006. - ISSN 0016-7029. - EISSN 1531-8397.
Внешние системы:	DOI: 10.1134/S0016702912120075; SCOPUS: 2-s2.0-84870595449;
Реферат:	eng: 430 chemical analyses of rocks and their diamondiferous potential are used to identify correlations between the diamondiferous potential of rocks and their petrochemical parameters. Samples for this research were collected from selected intervals of core materials, which were also examined for diamond content (a few samples from each interval), from the Nyurbinskaya, Botuobinskaya, Internatsional'naya, Mir, Aikhal, Yubileinaya, Satykanskaya, Udachnaya-West, and Udachnaya-East pipes. Typochemical indications of diamondiferous potential are TiO2 and K2O concentrations and the CaO/MgO ratio. System models developed for diamondiferous kimberlites allowed distinguishing two trends of their compositional variability. One of the trends is defined by the negatively correlated TiO2 and K2O concentrations of the rocks. This trend is discrete and can be statistically justifiably subdivided into seven segments, each of which represents a population of compositions produced under similar physicochemical conditions. Experimental data confirm that this trend can be closely related to the diamondiferous potential. Diamond richest kimberlites are practically free of TiO2, whereas diamond poorest ones contain as much as 3% of this oxide. The former and the latter rocks were produced at the greatest and shallowest depths, respectively. The other trend is exhibited in all populations and subdivides them into discrete groups (varieties of the populations) with systematically decreasing CaO/MgO ratio. This parameter is nonlinearly correlated with the diamondiferous potential, and its increase corresponds to a systematic increase in the melting temperature of the source material. Certain kimberlite populations contain anomalously high K2O concentrations, perhaps, because of mantle metasomatism or the presence of fragments of oceanic crustal material in the magma generation region. In these instances, numerous diamonds could crystallize in the parental melts under high pressures (&100 kbar). The paper presents statistical analysis of pair regressions of the contents of indicative oxides and diamondiferous potential and a graphical multiple-link model for correlations between concentrations of major oxides and diamondiferous potential. Tests of the predictions of diamondiferous potential on the basis of chemical parameters confirm that these predictions are accurate in 85-90% of the instances. © 2012 Pleiades Publishing, Ltd.
Ключевые слова:	diamondiferous potential; kimberlite; population analysis; physicochemical property; metasomatism; magma; kimberlite; igneous geochemistry; diamond; concentration (composition); chemical composition; chemical analysis; Diamond deposits; Titanium dioxide; Rocks; Minerals; Mineralogy; Forecasting; Diamonds; Coremaking; Chemical analysis; TiO; System models; Source material; Population model; Population analysis; Physicochemical conditions; Pair regression; Multiple links; Mantle metasomatism; Major oxides; Magma generation; kimberlite; High pressure; diamondiferous potential; chemical composition; Core material; Compositional variability; Chemical parameters; Chemical compositions; Crustal materials;
Издано:	2012
Физ. характеристика:	с.988-1006