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The problems of large-scale contamination of the Shufan volcanic plateau (Primorye) basalts with selective melts from xenoliths are discussed. Silico-alkaline liquids that are selectively extracted from xenoliths mix only to a limited extent with the basalt melt, and form granophyre bands that give lavas a taxitic texture. The unique compositions of buchites (pelitic xenoliths chemically modified with a diffusion interaction with basaltic magma and selectively molten politic xenoliths) are characterized. The mineral associations of buchites are represented by highly ferriferous cordierite (sekaninaite), ultra-ferriferous hercynite, (Al, Zr) Fe-armalcolite, Zr-ilmenite, mullite, sillimanite, high-lanthanum monazite, and a barium–phosphate–aluminosilicate phase. The features of the chemical and mineral composition of buchites reflect the accumulation of refractory elements (Al, Fe, Ti, Zr, Ni, and Cr) in the restitic material of xenoliths, followed by the formation of ultra-aluminous, ultra-ferriferous, and initially immiscible metal-silicate composition. Low Pb isotopic ratios in the Shufan basalts indicate selective contamination with material of the ancient cratonic basement. A steady increase in these values is observed for basalts contaminated with the upper crustal material, which also reflects the isotopic composition of buchites.

Composition and typomorphic features have been studied for rare earths-bearing minerals from the central part of the Malmyzhskoe gold-copper-porphyry deposit. This deposit is located in the Russian Far East, approximately 220 km northeast from Khabarovsk city. The deposit porphyry clusters occur as diorite and granodiorite stocks of Cretaceous age intruding the hornfels-altered siltstone and sandstone sedimentary sequences. The rare earth mineralization in ores and altered host rocks is represented by anhydrous phosphates (monazite, xenotime, REE -bearing apatite), silicates (allanite, huttonite), fluorocarbonates (synchysite) and oxides (davidite). These minerals occur there as individuals, but also they shows reactionary relations between them and ore minerals in altered rocks. It means that rare earth minerals in the central part of the Malmyzhskoe deposit participated actively in metasomatic processes, and likely they have a hydrothermal origin.

В статье приведены новые данные об акцессорных минералах в пеплах, образовавшихся при фреатическом извержении вулкана Корякский в 2008—2009 гг. Охарактеризованы формы выделения, состав и свойства гранатов, корунда и дельталюмита, муассанита, сульфидов таллия, самородных металлических и углеродных фаз, включая алмаз, а также предположительно абиогенных конденсированных органических соединений. Особенностью корякских алмазов является очень мелкий размер и кубический габитус, что может свидетельствовать об их кристаллизации из газовой фазы в условиях значительных пересыщений по углероду. Обнаружения в пеплах на Корякском вулкане разнообразных по форме и цвету частиц и нитей конденсированных органических соединений подтверждает ранее сделанный вывод о систематическом неорганическом синтезе на современных вулканах достаточно высокоорганизованных предбиологических форм органического вещества.

The Kirganik copper–porphyry deposit is situated in the central part of the Sredinnyi Mountain Range of Kamchatka and is confined to fields of development of potassic orthoclase metasomatite and hypabyssal intrusions of shonkinite. Platinum group metals (PGMs), such as merenskyite, kotulskite, keithconnite, and temagamite, were discovered in the chalcopyrite–bornite and chalcopyrite–bornite–chalcosine ore of the deposit for the first time.

The characteristics of formation of the opal mineralization in the host rock within Mutnovskaya volcanic zone were studied. The type of metasomatic rock alteration and its consecutive order were established. The results of study allowed identifying the mineral inclusions in opals, which was linked to the metalliferousness of the Mutnovsky hydrothermal system. Probable mechanism of opals formation within the North Mutnovskaya zone is considered, and its characteristics are compared to those from the opal field Raduzhnoye, Primorye.

Quantitative X-ray fluorescence determination of major rock-forming oxides (Na 2 O, MgO, Al 2 O 3 , SiO 2 , P 2 O 5 , K 2 O, CaO, TiO 2 , MnO and Fe 2 O 3 ) and some microelements (Sr and Zr) was performed in the samples of 143 cm-long sediment core of Lake Baunt (Buryat Republic) by the wavelength-dispersive X-ray fluorescence analysis on the S8 Tiger spectrometer. Calibration curves were obtained by measuring the certified reference materials of the sedimentary rocks. Both analyzed and reference samples were prepared as glass beads by fusion of 110 mg of sample with1.1 g of lithium metaborate. We have used 110 mg mass to ensure the formation of beads with appropriate 10 to 12 mm size across to be measured by the spectrometer with8 mm mask. Rh Kα Compton line was used as a background standard for Sr and Zr determination. The repeatability did not exceed the allowable standard deviation for a wide range of concentrations. Results of major rock-forming oxides determination were compared with the data of spectrophotometry and flame photometry techniques, results of Sr and Zr determination were compared with the data of synchrotron radiation excited X-ray fluorescence technique. All results of the X-ray fluorescence analysis were accepted as satisfactory. Quantitative analysis of each centimeter of Lake Baunt sediment core allowed building first reconstructions of the local environment during the last 7000 years with unique resolution of about 100 years. Keywords: wavelength-dispersive X-ray fluorescence analysis, synchrotron radiation induced X-ray fluorescence analysis, sediments, paleoclimate (Russian) DOI: http://dx.doi.org/10.15826/analitika.2017.21.1.003 A.A. Amosova, V.M. Chubarov,E.V. Kaneva, Iu.N. Markova Vinogradov Institute of Geochemistry, Siberian Branch of Russian Academy of Sciences, ul. Favorsky , 1A, Irkutsk , 664033, Russian Federation

For the first time, the particles of organic polymers have been found in the products of modern volcanism in Kamchatka. They are probably of abiotic origin, which makes it possible to interpret the results of studies from the perspective of volcanic-atmospheric-oceanic hypothesis about the origin of life on the Earth by A. I. Oparin–J. Haldane.

Chances for estimating the FeO/Fe2O 3 tot ratio in rocks by the K and L series of X-ray fluorescence spectra are studied. The errors in the determination of FeO/Fe2O 3 tot by the intensity ratio of the Kβ2,5/Kβ1,3 and Lβ/Lα1,2 lines are compared. The relative standard deviation of determining FeO using a set of 49 standard samples of eruptive rocks varies in the range 5–16%, depending on the ratio FeO/Fe2O 3 tot and the concentration of FeO. The better precision is attainable for a ratio above 0.45 at a FeO concentration in the range 5–15%. For samples of andesites and basalts, the relative standard deviation is better than 4%, for rocks of the granite family it is 23% at FeO concentrations below 3%. For samples of metamorphic and sedimentary rocks, the error of FeO determination is higher than that for the eruptive ones. For samples with the ratio FeO/Fe/Fe2O 3 tot < 0.25, the deviation may exceed 30 rel %. In contrast to chemical analysis, the X-ray fluorescence method appears advantageous in time and cost of sample preparation and can be used for routine analysis in geochemical research.

Some varieties of magnetite with relatively high content of SiO2 (about 5,4%) were found by the authors. Silica-bearing magnetite of the Korshunovskoye scarn deposit is enriched in Ca (up to 1.99% CaO), Al, Mg, Ti. In serpentinites of the Atlantic and Indian oceans Si-magnetite forms pseudomorphs on Cr-spinel and includes impurities of Mn (to 3.5% MnO), Cr, Mg and Al. Distinct quantitative correlations of silica and other trace elements are observed. The authors suggest possible models of cation distribution in Si-magnetites and suppose that emplacement of silica into the magnetite crystal structure is due to the presence of chlorine in mineral-forming solutions.

The problem of similarity of explosions is related inseparably with the mechanism of energy expenditure during their development. By mechanism here, is understood the investigation of those courses of energy expenditure which are decisive. Three such courses can be shown for cratering (dumping) explosions, depending on the role of which the law of similarity will be changed. The energy in the case of cratering explosions is expended on fracturing the massif or deforming it. This course of energy expenditure is determined by the volume of the medium, within the limits of which its destruction or deformation takes place. The energy expenditure in this case should be proportional to the volume of rock shattered, i.e., E~V. For the explosion of a charge with weight Q, for which this course of energy expenditure takes away a certain part q~, the relation