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Data from the study of minerals of the liquidus association (olivine and spinel) from high-Mg basalts (up to 10 wt % MgO) of Menshyi Brat Volcano (Iturup Island) are reported. Based on these data, it was possible to estimate the water content and to study the evolution of volatile components in the primary basic magmas that formed the Medvezhia Caldera (Irurup Island), for the first time. It is shown that the initial water content in melts could reach 5 wt % at an oxygen fugacity corresponding to the NNO + 0.4 buffer. The further evolution of magmas included continuous degassing at a depth of ≤8 km. Hydrous fluid separated from basic magma could play a significant role in the formation of large crustal chambers of siliceous magma participation in catastrophic caldera eruptions.

For the Permian–Triassic foidite and meimechite lavas of Polar Siberia, both the whole-rock petrochemistry and geochemistry and that of melt inclusions in olivine phenocrysts from the same rocks have been demonstrated to be similar. In addition, their isotope characteristics imply the possibility of their generation from an abyssal parental melt compositionally resembling a high–Mg alkaline picrite.

The probability of obtaining of ash-free coal extracts, so-called “hyper-coals,” has been shown for coals of the Pechora basin for the first time. The ash content in them does not exceed a few percent, whereas initial coals contain up to 20% ash. High-resolution 13C NMR shows the similarity in the structure of the initial coal and the extract. It is demonstrated that the solvent selected for hyper-coal extraction is not chemically inert, and the products of interaction of N-metylpyrrolidone and organic matter of coal are present in the composition of the extracts obtained.

The primary melt and fluid inclusions in regenerated zonal crystals of olivine and homogeneous phenocrysts of olivine from kimberlites of the Udachnaya-East pipe, were first studied by means of microthermometry, optic and scanning electron microscopy, electron and ion microprobe analysis (SIMS), inductively coupled plasma mass-spectrometry (ICP MSC), and Raman spectroscopy. It was established that olivine crystals were regenerated from silicate–carbonate melts at a temperature of ~1100°C.

It has been demonstrated for the first time that the isotopic compositions of carbon (δ13C) in magmatic calcites from the Udachnaya–East pipe kimberlite groundmass varies from–2.5 to–1.0‰ (V-PDB), while those of oxygen (δ18O) range from 15.0 to 18.2‰ (V-SMOW). The obtained results imply that during the terminal late magmatic and postmagmatic stages of the kimberlite pipe formation, the carbonates in the kimberlite groundmass became successively heavier isotopically, which indicates the hybrid nature of the carbonate component of the kimberlite: it was formed with contributions from mantle and sedimentary marine sources.

Palynological (dinocysts) and geochemical data were compared for the first time for Paleogene sediments of borehole no. 8 (settlement of Russkaya Polyana, Omsk oblast). The layers with a concentrated amount of dinocysts of the genus Pseudokomewuia (20.5% of the palynocomplex) are characterized by higher contents of Fe, P, Ti, Nb, Ta, and W. The microphytoplankton bloom (an analog of the present-day red tides) in the late Oligocene Turtas Lake–Sea was probably caused by a greater contribution of nutrient substances from the continent during the transgression of this basin. Comparative analysis of the geochemical features of marine and continental Paleogene sediments from borehole no. 8 showed that the Turtas basin was either freshwater or had brackish water.

The composition of volatile components in picroilmenites from Yakutian kimberlitic pipes of various ages (the Olivinovaya, Malokuonapskaya, and Udachnaya–East pipes) was studied for the first time by means of gas chromatography–mass spectrometry (GC-MS). It was shown that picroilmenites and olivines from same kimberlitic pipes contained volatile components of close composition, whereas these components were quite different in these minerals from different pipes. These features point to a common source and represent the specificity of the magma chamber formed under the pronounced influence of hydrocarbons with their derivates, as well as nitrogen-, chlorine-, and sulfur-containing compounds. The fraction of hydrocarbons and derivates in the composition of volatile matter is as high as 99%, including 9.7% of chlorine- and fluorinecontaining compounds.

The composition of volatiles from fluid and melt inclusions in olivine phenocrysts from Yakutian kimberlite pipes of various ages (Olivinovaya, Malokuonapskaya, and Udachnaya-East) were studied for the first time by gas chromatography–mass spectrometry. It was shown that hydrocarbons and their derivatives, as well as nitrogen-, halogen-, and sulfur-bearing compounds, played a significant role in the mineral formation. The proportion of hydrocarbons and their derivatives in the composition of mantle fluids could reach 99%, including up to 4.9% of chlorineand fluorine-bearing compounds.

The results of study of crichtonite group minerals in pyropes from the Internatsionalnaya kimberlite pipe are reported. Most of the studied samples are characterized by high concentrations of Sr, Ca, Na, and LREEs in comparison with minerals of the LIMA series from kimberlites of South Africa, whereas the average concentrations of Ba and K are significantly lower. Crichtonite group minerals in pyropes are characterized by predomination of Na over K in most samples and by a high concentration of Al2O3 (up to 4.5 wt %). Findings of inclusions of crichtonite group minerals with high concentrations of incompatible elements provide evidence for the metasomatic origin of host chromium-rich pyropes.

The results of study of rutile inclusions in pyrope from the Internatsionalnaya kimberlite pipe are presented. Rutile is characterized by unusually high contents of impurities (up to 25 wt %). The presence of Cr2O3 (up to 9.75 wt %) and Nb2O5 (up to 15.57 wt %) are most typical. Rutile inclusions often occur in assemblage with Ti-rich oxides: picroilmenite and crichtonite group minerals. The Cr-pyropes with inclusions of rutile, picroilmenite, and crichtonite group minerals were formed in the lithospheric mantle beneath the Mirnyi field during their joint crystallization from melts enriched in Fe, Ti, and other incompatible elements as a result of metasomatic enrichment of the depleted lithospheric mantle.

The primary fluid and melt inclusions in regenerated zonal crystals of olivine from kimberlites of the Malokuonapskaya pipe were first examined by means of microthermometry, optic and scanning electron microscopy, and Raman spectroscopy. The high-pressure genesis of homogenous central parts of the olivines was revealed, probably under intense metasomatism at early hypogene stages with subsequent regeneration in the kimberlitic melt. The olivine crystals were regenerated from silicate–carbonate melts at about 1100°C. The composition of the kimberlitic melt was changed by way of an increase in the calcium content.

ISSN 1028334X, Doklady Earth Sciences , 2015, Vol. 463, Part 2, pp. 828–832. © Pleiades Publishing, Ltd., 2015.Original Russian Text © N.V. Sobolev, A.V. Sobolev, A.A. Tomilenko, V.G. Batanova, A.V. Tolstov, A.M. Logvinova, D.V. Kuz’min, 2015, published in Doklady Akademii Nauk,2015, Vol. 463, No. 5, pp. 587–591.

Migration of magmas though the subcontinental lithospheric mantle is one of the key processes driving in the evolution of its modal composition, and the introduction of incompatible elements into the host peridotites. Mantle metasomatism can explain a num� ber of processes, from the formation of diamond to the genesis of continental and oceanic mafic magmas (12, 13). Many types of mantle metasomatism, mostly related to variations in the composition of metaso� matic agents, are distinguished. Previous studies of peridotitic massifs and contact mantle xenoliths (peri� dotites with pyroxenite veins) demonstrated that inter� action between peridotite and melt migrating through fractures or intergranular spaces resulted in significant mineralogical, chemical, and isotope heterogeneities in the lithospheric mantle. Consequently, contact xenoliths carried to the surface by alkaline basaltic magmas are an important source of information on the processes of migration of mantle melts and their inter� action with peridotites of the lithospheric mantle.

Harzburgite massifs of the ophiolite associationformed under supersubduction environments are traditionally considered as chromitebearing and perspective for discovery of highchromium ores [1, 2].However, the deposits of chromium ores are knownnot only in all dunite–harzburgite ophiolite massifs.The problem of significant differences between thecompositions of peridotites in massifs hosting largechromite deposits and those in massifs with small oreoccurrences is still open. The textures of residual peridotites (harzburgite and lherzolite) in ophiolites preserve traces of residual deformations that proceeded insubsolidus solid–plastic flow of mantle rocks [3]. Thelocation of ore bodies and host dunite in relation tomantle deformational textures and critical horizonshas been considered in some publications [4, 5], butthe revealed textural criterions may be mostly appliedas local for searching for bodies in potential ore fields.Variations in the general petrochemical composition of mantle peridotites of ophiolites are mainlycontrolled by the depletion degree of rocks in thecourse of partial melting of mantle matter. An increasein peridotite depletion results in an increase in themagnesium mole fraction of rocks and a decrease inthe contents of SiO

138 Mantle metasomatism and partial melting are the main processes that change the composition of the lithospheric mantle. Metasomatic enrichment in mantle xenoliths and peridotite massifs is evident from the presence of newly formed, mainly hydrous miner� als (modal metasomatism), as well as from enrichment of peridotitic minerals in incompatible elements (cryptic metasomatism). In most cases metasomatic enrichment in mantle xenoliths brought up by kimber� lites and alkaline basalts is registered only as a change

Olivine is one of the most abundant minerals inupper mantle rocks, such as garnet and spinel peridotites of HP/UHP collisional zones and xenoliths inkimberlites and alkali basalts, as well as mineral inclusions in diamonds [1–3]. Having a simple chemicalcomposition, it contains some minor elements ofpetrogenetic importance. In spite of the widespreadabundance of olivine in such rocks, there are only afew studies of its minorelement composition (see thereview in [3]). This is explained by the low concentrations of minor elements in olivine, usually not exceeding 0.1 wt % (except for NiO and MnO), which makesanalytical difficulties for their measurements duringcommon electron microprobe investigations [4].In this paper we discuss the first study of the minorelement composition of olivines from peridotites ofthe wellknown Kokchetav massif in Northern Kazakhstan. These peridotites have an unusual chemicalcomposition characterized by a high concentration ofFeO (13–22 wt %), TiO

The specifics of the morphology, internal structure, and composition of olivine, one of the major rock� forming minerals of ultrabasic and basic rocks, contains valuable information on the conditions of its formation and are widely used in petrology [11, 8, 3, 7, 12]. One of its important characteristics is zoning, which is most pronounced in lunar [8] and Martian [2] meteorites. Olivine exhibits both normal and reverse zoning, with the core–rim difference reaching 25 mol % forsterite. However, this phenomenon is uncommon in the ter� restrial intrusive rocks, because subsolidus diffusion usually “smoothes out” the initial compositional het� erogeneities of the mineral. At present, the available data are reduced to scarce olivine grains with zoned distribution of major (Fe and Mg with Fo gradient of 8–10 mol % [1, 4, 5]) and trace elements Ca, Ni, as well as Al, Cr, and P [4, 9]. Therefore, the find of zoned olivines with the core–rim difference more than 20 mol % Fo in the magmatic rocks of the Noril’sk district is a unique phenomenon not only for this region but also for ultrabasite–basite complexes around the world. The Noril’sk district is located in the NW Siberian trap province. It consists of the rocks of the crystalline basement and platform cover represented by the Early Cambrian–Late Permian terrigenous–carbonate rocks and Early Triassic basalts. Numerous ultrabasite– basite hypabyssal massifs in the forms of chonoliths and bodies of irregular shape are localized among the sedimentary and volcanic rocks of the area. Distinctly differentiated intrusions are combined into the pro� ductive Noril’sk complex, which is characterized by an elevated average weighted MgO content (10–12 wt %) relative to tholeiitic basalts predominant in the section (6–7 wt %). Some of them contain superlarge Pt– Cu–Ni deposits (Talnakh, Oktyabr’skoe, Noril’sk�1), whereas others are either weakly mineralized or bar� ren. Their age relations with volcanic rocks were not established exactly, because in most cases the intru� sions are localized in the underlying sedimentary rocks. One of the representatives of this type of magmatic complexes is the massif studied by us in the eastern part of the area, in the Mikchangda River basin. It is located in the Devonian carbonate–terrigenous rocks