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One of the pivoting problems in the genesis of magmatic deposits is the role of silicate melt in the origin of sulfide ores. A way of solving this problem is to compare massifs with different mineralization, using contents of major and trace elements in the rocks. However, intrusions of the Norilsk intrusive complex are rarely compared with one another in terms of ore composition and volume in them. This paper is the first geochemical data, all of which were acquired with the application of modern analytical techniques, on the Chernogorsky intrusion in the Norilsk trough. The structure and composition of this intrusion are well comparable to the intrusions of the same complex hosting the uniquely large deposits: Talnakh, Kharaelakh, and Norilsk 1. The weighted mean composition of the Chernogorsky intrusion (wt %) is as follows: 47.2 SiO2, 0.62 TiO2, 16.7 Al2O3, 9.94 FeO, 0.16 MnO, 11.7 MgO, 11.3 CaO, 1.53 Na2O, 0.46 K2O, 0.07 P2O5, and 0.18 Cr2O3,, and the ratios of trace elements (La/Sm)n = 1–2, (Gd/Yb)n = 1.2–1.4, and (Th/Nb)n = 1–4 are same as typical of other rocks of the Norilsk complex. The ores of the Chernogorsky intrusion are close to the ores of Norilsk 1, their Cu/Ni ratio slightly exceeds 1, and the Pt + Pd = 5–6 ppm on average. However, the predicted resources of metals in this massif (0.8 Mt Cu + Ni and 0.5 kt Pt + Pd) are 140 times lower than the resources of the Kharaelakh intrusion (113 Mt Cu + Ni, 17.5 kt Pt + Pd), and 50 times lower than in Talnakh (40 Mt Cu + Ni, 8.3 kt Pt + Pd). This confirms that the ore content in an intrusion does not depend on the composition of its silicate rocks, and hence, the compositions of these rocks cannot be used as an exploration guide for new deposits.

Interfacial separation of components of extractants based on di-(2-ethylhexyl)phosphoric acid (di-2EHPA) in toluene and a mixture of di-2EHPA with trioctylamine in toluene has been studied in the course of treatment with aqueous sodium hydroxide solutions yielding an organic phase and an aqueous colloidal solution of di-2EHPA sodium salt. Conditions have been found for the isolation of almost pure di-2EHPA and toluene, as well as di-2EHPA and a trioctylamine solution in toluene. The aqueous colloidal solutions have been studied by conductometry, dynamic light scattering, and 1H-NMR spectroscopy. The considered systems are promising to be used in hydrometallurgy for improving parameters of extraction of metals and their concentrating in re-extracts.

The dunite–wehrlite–clinopyroxenite–gabbro massif in Eastern Chukotka, a key object for geodynamic reconstructions of the Vel’may terrane, which represents one of the segments of the southern border of the Chukotka folded system (Chukotka microcontinent, or Arctic Alaska–Chukotka microplate), is investigated. Mineralogical and petrological–geochemical studies of rocks of this massif are carried out. A comparative analysis of the primary mineralogy and formation conditions of cumulative rocks of dunite–wehrlite–pyroxenite–gabbro assemblages from modern island-arc systems, mantle transition zones, and crustal sections of ophiolites and ancient island arcs shows that the rocks studied are cumulates crystallized from a tholeiitic melt in an intraoceanic island arc at a moderately high pressure. The 40Ar/39Ar age of magnesian hornblende from gabbro indicates the massif was formed no later than in the Early–Middle Jurassic. The petrological and geochemical modeling suggests that the analyzed olivine clinopyroxenites and gabbros are probable plutonic comagmates of the Late Triassic island-arc basalts and dolerites of the Vel’may terrane. The arc segment represented by these rocks of the Vel’may terrane was probably part of the system of island arcs which had been reconstructed in this region for the age interval of 163 to 230 Ma. In addition, there is a tendency for the rejuvenation of the Middle Triassic–Late Jurassic island-arc magmatism in the direction from west to east, namely, from the South Anyui terrane of Western Chukotka through the Vel’may terrane of Eastern Chukotka to the Angayucham terrain of Alaska.

The extraction of iron(III) with tributyl phosphate from bromide aqueous solutions in the electrochemical processing of natural waters and brines was studied. It was found that iron(III) is extracted from solutions of alkali metal bromides in the form of the complex salt MFeBr4 at a salt concentration of more than 4 M. Extraction increases in the series KFeBr4 < NaFeBr4 < LiFeBr4. Extraction products are largely susceptible to electrolytic dissociation in the organic phase. The optimal conditions for the extraction of iron(III) bromide and its return to the technological process are determined.

Significant extraction degree of calcium and yttrium chlorides with solutions of the corresponding tetraphenylborates in tributyl phosphate has been revealed, due to the formation of mixed complex compounds in the organic phase. It has been shown that lithium, calcium, and yttrium tetraphenylborates are significantly dissociated in the organic phase. The process has been studied by conductometry. Based on the obtained data, it has been suggested that the formation of mixed halide complexes is owing to the high energy of the solvated ion pairs [CaLn]2+(A−)2 and [YLm]3+(A−)3 in organic solutions, which is significantly decreased upon the exchange of large tetraphenylborate anions with small chloride anions, possibly with the formation of solvated ion pairs with a lower charge of the cationic part of the complex [CaLn−1Cl]+A− or [YLm−2Cl2]+A−

Detailed mineralogical and melt and fluid inclusion constraints on magma storage, and the evolution of melts, are presented for the large-volume caldera eruption on the Vetrovoy Isthmus on Itutrup Island (Kuril Islands, Russia). The shallow magma reservoir beneath the Vetrovoy Isthmus is composed of a mush of plagio-rhyolitic melt, phenocrysts and the products of peritectic reaction(s). The melt appears to have formed as a result of partial melting of previously erupted rocks, which probably had andesitic to basaltic compositions and were metamorphosed into amphibole-bearing assemblages. The breakdown of amphibole in the partially melted precursor rocks led to the formation of early Mg-rich clino- and orthopyroxene, along with plagioclase and Fe–Ti oxides, and the release of aqueous fluids. Variations in fluid pressure are recorded by a strong increase of An contents in plagioclase. Crystallization took place at around 850°C with pressure ranging from 0·9 to 3 kbar. This study demonstrates that dacitic magmas erupted during the course of a 20 kyr voluminous eruption were the result of mixing between plagio-rhyolitic partial melts and the breakdown reaction minerals (i.e. pyroxenes, plagioclase and Fe–Ti oxides). Plagioclase and quartz were the last minerals to crystallize from these melts prior to eruption.

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.

The complex niobium–rare earth pyrochlore–monazite–crandallite ores of the Tomtor deposit, located in the Siberian Arctic, should be considered as a new type of rare metal materials. The major valuable components of the ore are niobium (1.63–16.4%), rare earth elements (2.2–27.8%), yttrium (0.18–2.9%), and scandium (0.015–0.15%); associated components are titanium, vanadium, aluminum, and phosphorus. Because of the irregular distribution of the rare earth metals and niobium according to grain size, the extremely finely dispersed nature of the minerals and their close interpenetration to each other, ore processing by gravitation and flotation is not successful. The processes studied for the treatment of the Tomtor ores use direct alkaline-acid leaching to open the ore. A problem in the first stage of alkaline leaching is the high aluminum content, which decreases the activity of sodium hydroxide and alkaline-earth metals, which are bound to phosphorus. Ore processing using alkaline-nitrate and alkaline-chloride leaching was proposed and investigated. The first variant was used to obtain rare earth and scandium materials and a niobium–titanium concentrate, which can be a stock material for processors who use chlorination for the processing of ores and concentrates. The second variant is a complex advanced ore processing scheme with electrochemical regeneration of the waste chloride solutions obtaining sodium hydroxide, hydrochloric acid, and chloridizing agents. Moreover trisodium phosphate is used for purification of the waste mother liquors from metal cations. The complex salt, NaAlCl4, is proposed as the chloridizing agent for the decomposition of the niobium–titanium concentrate. The recovery of rare earth metals in the second variant of processing is about 95%; while for niobium and titanium, this value is 92–94%.

Generalization of available literature and new original data showed that the Early Cretaceous high-Mg alkaline magmatism is confined to the ancient Lambert rift zone. Alkaline ultramafic rocks developed in the areas of this zone (Jetty Oasis, western flank of the Beaver and Radok lakes, Fisher and Meredith massifs) were derived through melting of metasomatized continental mantle at ~1270°С and at depths of 130–140 km. Variations of major and trace-element composition and the wide range in olivine composition (Fo91–Fo80) are consistent with its change through intrachamber crystallization. The average values of initial isotope composition of ultra-alkaline high-Mg basalts are as follows: 143Nd/144Nd—0.512485, 87Sr/86Sr—0.70637, 207Pb/204Pb—15.671, 206Pb/204Pb—18.391, 208Pb/204Pb—38.409. They are close to the model ЕМII source and can be arbitrarily taken as the preliminary assessment of isotope composition of a source of Mesozoic melts. Based on lithophile element and isotope compositions, the alkaline high-Mg basaltic magmatism is thought to be related to the thermal impact of the Kerguelen plume on the lithospheric mantle of East Gondwana 120–110 Ma. Similar ancient deep-seated metasomatized eastern Gondwanan mantle, which contains carbonates and biotite and has an age of 2.4 Ga, was found in southern East Antarctica as well as in the north within eastern India.

The objects of study are Triassic hypabyssal diamondiferous kimberlites with an age of 220–245 Ma, containing macrocrysts of unaltered olivine. The latter are close in the time of formation to the main stage of intrusion of the Siberian Trap Province (252 Ma), which lasted less than 1 Myr. A comparative high-precision analytical study of the Ti, Ca, Cr, and Al impurity patterns in about 1000 olivine macrocryst samples with a forsterite content Fo = (100Mg/(Mg + Fe)) of 78 to 93 has demonstrated the effect of traps on the lithospheric composition. A comprehensive comparative study of diamonds from northern placers and Triassic kimberlites, including determination of their carbon isotope composition, was performed. Chromatography–mass-spectroscopic analysis of submicron fluid inclusions in diamonds from northern placers and kimberlites has shown predominant hydrocarbons of a wide range of compositions and subordinate contents of N2, H2O, and CO2. These findings, together with the results of previous studies of subcalcic Cr-pyropes and diamonds found in the Lower Carboniferous gritstones of the Kyutyungde graben, lead to the conclusion that the Toluopka kimberlite field is promising for Paleozoic kimberlites. The results of comprehensive studies of diamonds and indicator minerals and U/Pb isotope dating of numerous detrital zircon samples from the basal horizon of the Carnian Stage (Upper Triassic) of the Bulkur site in the lower reaches of the Lena River suggest the presence of diamondiferous kimberlites within the northeastern Siberian Platform. The age of the probable primary diamond sources in the study area can be evaluated by an integrated U/Pb isotope dating of zircons, perovskites, and rutiles from the developed diamond placers and the basal horizon of the Carnian Stage.

The process of recovery by direct extraction of metal bromides from calcium chloride brines using mixtures of molecular iodine with tributyl phosphate has been studied. It was found that iodine significantly increases the recovery of the bromides of alkali and alkaline earth metals due to the formation of hydrophobic iodine complexes with the halide anions. Bromides of calcium and lithium are the most selectively extracted. The extracted complexes significantly dissociate into ions in the organic phase. The extraction of calcium halide over a wide range of its concentration in an aqueous solution results in the extraction of a mixed chloride-bromide salt. This is due to a significant difference in the separation factors for bromide and chloride ions in the interphase exchange reactions for the halide ions of the inner and outer coordination spheres of the extracted complex.

The Matachingai River basin is known among the few ophiolitic complexes on eastern Chukotka as the southern boundary of the Chukotka Fold System (in terms of tectonics, the Chukotka microcontinent or a fragment of the Arctic Alaska–Chukotka microplate). This complex comprises tectonic blocks of residual spinel harzburgite with dunite bodies and pyroxenite, olivine gabbro, and leucogabbro veins; blocks of hornblende gabbro, diorite, and plagiogranite; and Upper Jurassic–Lower Cretaceous basaltic–cherty and cherty–carbonate rocks. The geological relationships of rocks within tectonic blocks, the compositions of primary minerals, the bulk geochemistry of rocks, as well as the strontium, neodymium, and lead isotopic compositions, make it possible to consider individual tectonic blocks of the complex as fragments of a disintegrated oceanic-type lithosphere that formed in a back-arc spreading center. The melts, crystallization products of which are represented by hornblende gabbro of blocks, olivine gabbro of veins, and basalts, separated from geochemically and isotopically heterogeneous mantle. Blocks composed of rocks with various modal composition are likely relicts of an oceanic lithosphere of different segments of a back-arc basin. The studied complex may be a lithosphere of one of the Middle–Late Jurassic back-arc basins. Fragments of these basins are retained in ophiolitic complexes on Great Lyakhovsky Island of the New Siberian Islands Archipelago, western Chukotka, and the Brooks Range in Alaska.

We studied combined effect of β-hairpin antimicrobial peptide tachyplesin I and cytotoxic agent cisplatin on tumor and normal human cell lines. MTT assay and flow cytometry showed that tachyplesin I selectively sensitized cancer cells to cisplatin in specified concentration ratios. In vitro experiments demonstrated that combined use of tachyplesin I and cisplatin allows decreasing the effective dose of the cytostatic thus reducing nonspecific toxicity.

A periodic character of the evolution of trap magmatism was inferred by many researchers from the fact that sequences of volcanic rocks consist of alternating units of lava flows and tuff. A new phase of studying magmatic rocks in the Siberian Platform was related to the possibility of apply high-precision geochemical techniques in studying trace elements and Sr, Nd, and Pb isotopic compositions. The use of these techniques made it possible not only to identify small individual cycles in the vertical sections of volcanic rocks but also to distinguish larger stages. The currently most widely acknowledged scenario of the origin of volcanic rocks involves three stages, during which oceanic-island basalts (OIB), transitional series (intermediate between OIB and WPB), and within-plate basalts (WPB) were formed. This scenario was inferred mostly from data on rocks in the western part of the Norilsk area (Kharaelakh Trough). This publication presents recently obtained data on the inner structure of the sequences of volcanic rocks and the geochemistry of basalts in the eastern part of the territory, where no rocks show transitional characteristics have ever been found. They can be classified into two types that have clearly different composition and occur in different areas. These types characterize two major stages of the origin of volcanic rocks: rift-related and trap magmatism itself. The rocks produced during these stages occur at neighboring territories.

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.

Tholeiitic melts from the Bouvet triple junction (BTJ) of rift zones in the South Atlantic are moderately enriched rocks with specific lithophile-element patterns. The high (Gd/Yb)n values (up to 2.5) in some tholeiite compositions suggest the presence of garnet in the mantle source of primary BTJ melts. The high Ni and low Mn contents of the most magnesian olivines determined by high-precision probe microanalysis suggest the presence of pyroxenite, along with typical peridotite, in the melting source. The unusually wide within-sample variation in the proportions of pyroxenitic component in the source region (XPx Mn/Fe = 0–90%) indicates different degrees of mantle heterogeneity beneath the spreading zone. Based on geochemical data, this component is a silica-oversaturated eclogite, reacting with peridotite to form olivine-free pyroxenite in the melting source. This component is probably represented either by subducted and recycled oceanic crust or by fragments of the ancient continental lithosphere buried into the mantle after the Gondwana breakup. The observed global and local mantle heterogeneities might have been developed during the complex geodynamic evolution of the Southern Ocean, whose opening was affected by the activity of the Mesozoic Karoo–Maud–Ferrar plume and multiple jumps of the spreading axes, which led to the involvement of fragments of the early oceanic lithosphere in the melting process.

The Chuktukon niobium-rare earth elements ore deposit is located in Siberia (Russia). Weathered carbonatite crusts are the basis of the ore deposit. The deposit itself is 3.5 km in length, about 800 to 1400 m in width and up to 200–300 m in thickness. The ores are composed of iron-manganese oxides (hydrogoethite, hematite, psilomelane, pyrolusite) and contain 3–7 wt.% of rare-earth phosphates (florencite, monazite) and 0.5–1 wt.% of niobium oxide (pyrochlore). The ore is completely finely dispersed and consists of oxide particles formed of compact, dense aggregates which makes ore dressing as well as leaching of the rare and radioactive elements very difficult. Several options for processing of these ores have been considered: 1) reduction of the iron oxides to magnetite followed by beneficiation with magnetic separation to produce a rare metal concentrate; 2) processing of the rare earth elements (REE) containing minerals by direct alkaline-acid treatment; 3) processing of the ores using nitric acid leaching in an autoclave.

Cathodoluminescence (CL) microscopy studies were performed to unravel internal structures and zonations of carbonates from 6 unaltered hypabyssal kimberlites from several Mesozoic - Paleozoic kimberlite pipes of the Siberian craton. Different generations of prograde and retrograde carbonate grains/domains were identified. Most investigated kimberlite samples are unusually fresh and contain abundant unaltered olivine. Only minor amounts of carbonates of a primary magmatic origin were found; most carbonates are of secondary origin formed during late metasomatic or hydrothermal events. A rare carbonatite xenolith discovered in the Malokuonapskaya kimberlite contains abundant apatite and monazite; an apatite inclusion was detected in one zircon grain. Some apatites contain oriented lamellae of monazite. Early studies of the carbonate minerals in this xenolith demonstrated a trace amount of Sr; all these characteristics are typical of carbonatite. We conclude that carbonate minerals play a significant role in the evolution of hypabyssal kimberlites of the Siberian craton. The CL-studies of these minerals provide significant insights into their growth history and help to differentiate different parageneses, as either primary or secondary. Carbonatite xenoliths are of vital significance for the discussion of a possible genetic interrelation of kimberlite and carbonatite melts in the mantle. The present results may serve as a starting point for future studies of these carbonate minerals, using electron-microprobe, micro-PIXE or other high-resolution techniques. Future in-situ oxygen and carbon isotope analyses, as well as inclusions of melt, fluid, and minerals in different carbonate domains, will add essential new data with which to further unravel the genesis of the kimberlite-carbonatite association.

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.

Comparative analysis of ultramafic meymechites of the Maimecha Suite and alkaline volcanics of the Ary-Dzhang Suite (foidites (nephelinites, analcimites, limburgites, etc.) and melilitites) has shown their consanguinity, which indicates their relationship with the same magmatic system periodically producing large amounts of alkaline ultramafic melts. We have studied the petrogeochemical and mineralogical compositions of rocks and melt inclusions in the hosted olivines. The rocks of the Maimecha and Ary-Dzhang Suite differ considerably in MgO content, which is well explained by the accumulation of olivine. The inclusions in olivines from the meymechites and the rocks of the Ary-Dzhang Suite correspond in composition to foidites. The trace and rare-earth element patterns are similar both in the foidites and meymechites and in the melt inclusions: They show negative anomalies of Rb and K and positive anomalies of Nb and Ta. The ratios of indicator elements (Nb/Ta, Ba/La, Ta/La, etc.) in the rocks of the Maimecha and Ary-Dzhang Suite are constant and almost independent of their Mg# values. The La/Yb ratio in the foidites is significantly higher than that in the meymechites and in the melt inclusions from their olivines, which indicates that the rocks of the Ary-Dzhang Suite resulted from the fractionation of highly magnesian alkaline picritoid melt.

Pyroxenite veins in mantle peridotites of the Unnavayam sheet of the Kuyul ophiolite terrane (Koryak—Kamchatka folded area) are composed of clinopyroxenite and websterite crystallized from a boninite-like melt. The host clinopyroxene-bearing spinel harzburgites are moderately depleted residues, whose mineral compositions and conditions of formation correspond to those of peridotites from mid-oceanic and back-arc spreading centers. Mantle peridotites of the Unnavayam sheet may have formed a part of the mantle wedge above a subduction zone and have been intruded by boninitic melts at a certain stage of their evolution.

Magmas forming large igneous provinces (LIP) on continents are generated by extensive melting in the deep crust and underlying mantle and associated with break-up of ancient supercontinents, followed by formation of a new basaltic crust in the mid-oceanic rifts. A lack of the unifying model in understanding the sources of LIP magmatism is justified by lithological and geochemical complexity of erupted magmas on local (e.g. a cross-section) and regional (a single and different LIP) scales. Moreover, the majority of LIP rocks do not fit general criteria for recognizing primary/primitive melts (i.e.

The paper reports the first results of the petrological studies of magmatic melts that formed siliceous pyroclastic deposits related to voluminous eruptions on Iturup Island. The caldera-forming eruptions of the Lvinaya Past and the Vetrovoy Isthmus, having similar features, resulted from the evolution of silicic melts that originated from partial melting of metabasalts. According to the mineral thermometry results, the melt was crystallized at ~800°C. The phenocrysts from the Vetrovoy Isthmus pumices were crystallized at

Mineralogical studies and U–Pb dating have been carried out on rutile included in peridotitic and eclogitic garnets from the Internatsionalnaya pipe, Mirny field, Siberian craton. We also describe a unique peridotitic paragenesis (rutile + forsterite + enstatite + Cr-diopside + Cr-pyrope) preserved in diamond from the Mir pipe, Mirny field. Compositions of rutile from the heavy mineral concentrates of the Internatsionalnaya pipe and rutile inclusions in crustal almandine-rich garnets from the Mayskaya pipe (Nakyn field), as well as from a range of different lithologies, are presented for comparison. Rutile from cratonic mantle peridotites shows characteristic enrichment in Cr, in contrast to lower-Cr rutile from crustal rocks and off-craton mantle. Rutile with Cr2O3 > 1.7 wt% is commonly derived from cratonic mantle, while rutiles with lower Cr2O3 may be both of cratonic and off-cratonic origin. New analytical developments and availability of standards have made rutile accessible to in situ U–Pb dating by laser ablation ICP-MS. A U–Pb age of 369 ± 10 Ma for 9 rutile grains in 6 garnets from the Internatsionalnaya pipe is consistent with the accepted eruption age of the pipe (360 Ma). The equilibrium temperatures of pyropes with rutile inclusions calculated using Ni-in-Gar thermometer range between ~ 725 and 1030 °C, corresponding to a depth range of ca ~ 100–165 km. At the time of entrainment in the kimberlite, garnets with Cr-rich rutile inclusions resided at temperatures well above the closure temperature for Pb in rutile, and thus U–Pb ages on mantle-derived rutile most likely record the emplacement age of the kimberlites. The synthesis of distinctive rutile compositions and U–Pb dating opens new perspectives for using rutile in diamond exploration in cratonic areas.

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 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 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 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.

Unaltered Mg-olivine (Fo = 85-94) is a predominant mineral of the kimberlite block (serpentine-free) of the Udachnaya-East pipe, and it prevails in peridotite xenoliths and as inclusions in diamonds. The kimberlite of this pipe, like a series of hypabyssal kimberlites in other regions, contains two main types of olivine macrocrysts according to their size and morphology: those rounded or irregularly shaped (olivine I) and euhedral phenocrysts (olivine II), which are usually no larger than 0.5 mm and very seldom reach 1 mm in size. This study was focused on several thousand olivine samples assigned both to olivines I and to olivines II, with a gradual transition between them. Particular attention was paid to the search for mineral inclusions in olivine and for phenocrysts with a clear zoning. In the phenocryst cores of homogeneous composition, we have revealed orthopyroxene inclusions as well as clinopyroxene (chrome-diopside and chrome-omphacite) inclusions with wide variations in the Na2O and Cr2O3 contents, significantly higher than the previously established ones: up to 6.00 wt.% Na2O and 4.23 wt.% Cr2O3. Convincing evidence for the high-pressure origin of the olivine macrocryst cores is the presence of pyrope inclusions with 1.41-9.14 wt.% &2O3, 4.64-6.61 wt.% CaO, and Mg# = 75.6-83.7 in six samples, which testifies to the high-pressure lherzolite paragenesis of the phenocrysts cores. The cores of the studied olivine phenocrysts are identical in the contents of Ni, Co, Ca, Cr, and Mn to olivines from diamonds and peridotite xenoliths. However, they differ significantly in the steady elevated Ti content, equal to 100-300 ppm for the majority of the phenocrysts, including those containing pyroxene and pyrope inclusions.

Petrological-geochemical data were obtained on the lamproites of the Gaussberg Volcano located at the eastern Antarctic coast and compared with data on the magmatic rocks developed in the East Antarctica and Indian Ocean in relation with the Kerguelen plume. It was shown that the lamproites were derived from the ancient Gondwana lithosphere repeatedly modified at the early stages of its evolution, including significant enrichment in volatiles, lithophile elements, and radiogenic Sr and Pb isotopes. The Gaussberg Volcano located on the eastern Antarctic continental margin falls in the distribution field of the Kerguelen plume, which formed 130 Ma within the incipient Indian Ocean and is continuing to operate at present, forming volcanic rocks of Heard Island in the last ka. Manifestations of alkaline magmatism at the Antarctic margin around 56 ka (Mt. Gaussberg) indicate a sublithospheric spreading of mantle plume in the southwestern direction.

The paper presents data on the petrology and geochemistry of plutonic rocks dredged from the Stalemate Fracture Zone, Northwest Pacific Ocean, during Cruise SO201-1 of the R/V “Sonne”. We proposed also the reconstruction of their formation conditions and interpretation of their tectonic evolution. The genesis of gabbroids found among plutonic rocks composing the Cretaceous–Paleogene basement of the northwestern part of the Pacific Ocean was related to magmatism at the ancient spreading center and provides record of the evolution of the parental magmatic melts of N-MORB. Along with related peridotites, basalts, and dolerites, these rocks can be attributed to the disintegrated the Cretaceous–Paleogene oceanic lithosphere of the Pacific Ocean. The shallow mantle beneath the ancient oceanic crust of this area is made up of depleted magmatic spinel lherzolite, harzburgite, and dunite. The fact that gabbro-diorite and diorite that are not genetically related to the rocks of the Cretaceous–Paleogene basement of the Northwest Pacific occur at the eastern termination of the Stalemate Fracture Zone possibly reflects the complicated structure of the tectonic collage of rocks of different age that were produced in different geodynamic environments and were later tectonically brought together near the frontal portion of the Aleutian island arc. Judging by the isotopic–geochemical characteristics of these rocks, they cannot be classed with the family of oceanic plagiogranites. Deformations of the oceanic basement can be discerned throughout the whole Stalemate Fracture Zone as brecciation and large-amplitude vertical displacements within the oceanic lithosphere.

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.

Investigations into an assessment of the efficiency of the sorption of copper and nickel, from the pulps deriving from the leaching of low-grade sulfide ores (Kingashsky deposit, Russia) by hydrochlorination, using the chelating resin Purolite S930, were carried out. The recovery characteristics obtained for the process solution were compared to that for synthetic solutions. At pH 2.7–3.0, copper, nickel, and cobalt recovery, for long resin contact times, exceeds 99%. For pulps, compared to that for the synthetic solution, a significant decrease in the rate of metal recovery was observed which is presumably related to the influence of silicic acid. The sorption concentration constants for copper, nickel, and hydrochloric acid and the resin loss due to attrition were estimated.

Previously unknown Lower zone ultramafic sequences are described beneath the Platreef in the northern limb of the Bushveld Complex (South Africa). The Lower zone is separated from the overlying mineralized Platreef sequence by intervals of country rocks, which are represented by granofels (agmatites) and shales and include thin sills of fine-grained Marginal zone norite and pyroxenite. The chemical compositions of olivine and orthopyroxene in the Lower zone of the northern limb are more primitive than those established for the western and eastern limb and indicate that the Bushveld parental magma should be more Mg rich than previously suggested and therefore may have been able to dissolve more Cr than indicated by known Marginal chilled rock compositions. Olivine and orthopyroxene compositions show multiple reversals within the Lower zone sections which are accompanied by coherent reversals in the Cu/Pd ratio. The style of reversals is consistent with a gradual mixing of fresh magma with more evolved resident liquid in the chamber. Olivine and orthopyroxene contain higher Ni in sulfide-poor Lower zone sequences and are Ni depleted in mineralized rocks, whereas the degree of sulfide mineralization correlates with the S content in the country rock. Assimilation of sedimentary sulfur resulted in sulfide saturation and formation of Ni-depleted silicates in ultramafic rocks. The extremely high Ni content in olivine (up to 0.66 wt % NiO at Mg # = 88) from S-poor ultramafic rocks is attributed to Ni enrichment in residual melt after massive crystallization of Ni-poor orthopyroxene adcumulates. Trace element compositions of the most primitive cumulates and minerals confirm that the enrichment of primary melt of the Bushveld Complex in some incompatible elements is an initial feature of its anomalous mantle source.

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

The origin of vast accumulations of nickel and platinum in some continental magmatic rocks is still enigmatic, but ultimately linked to silicate-sulfide liquid immiscibility. The exact composition of pristine sulfide melts has proved extremely difficult to document and understand, largely because of the ephemeral, reactive qualities and small quantities of such melts. Here we report the discovery of Fe-Ni sulfide melt globules highly enriched in noble metals (Pt, Pd, Au; 120 ppm total platinum group elements [PGE]) within an unusual high-Mg andesitic glass (8.2 wt% MgO, 57.3 wt% SiO2) dredged from the southern Mid-Atlantic Ridge, near the Bouvet triple junction. The composition of this glass indicates derivation of its parental silicate melt from a garnet pyroxenite mantle source with pronounced “continental” isotopic (Pb, Sr, Nd, Hf, Os, O) signatures. We infer that the chemical properties of this high-temperature (1250 °C) melt, notably high SiO2 and Ni (310 ppm) contents, promoted sulfide saturation at low pressures in a purely oceanic setting, and propose that this unique example, with its likely origin in the continental lithospheric mantle, may be a useful analogue for incipient Ni-PGE-sulfide melt generation and magmatic PGE enrichment.

The layered Bushveld Complex hosts a number of chromitite layers, which were found to contain significant amounts of zircon grains compared with adjacent silicate rocks. Cathodoluminescent-dark, partially metamict cores and transparent rims of composite zircon grains were analyzed for trace elements with SIMS and LA-ICPMS techniques. The cores are enriched in REE, Y, Th and U and are characterized by distinctly flatter REE patterns in contrast to those of the rims and transparent homogenous crystals. Zircon from the different stratigraphic units has specific Th/U ratios, the highest of which (1.5–4) occurs in a Merensky Reef zircon core. The Ti content of Bushveld zircon ranges from 12 to 52 ppm correlating to a crystallization temperature range of 760–930 °C. The geochemical characteristics of the first zircon generation are consistent with its high-temperature crystallization as the first major U, Th and REE acceptor from a highly-evolved residue of the high-Mg basalt magma, whereas the rims and coreless crystals have crystallized from percolating intercumulus liquid of new influx of the same magma. U-Pb SHRIMP dating of zircon cores and rims does not reveal a distinguishable difference between their ages indicating the absence of inherited zircon. Concordia ages of 2,051 ± 9 Ma (2σ, MSWD = 0.1) and 2,056 ± 5 Ma (2σ, MSWD = 0.05) for zircons from the Merensky Reef and the Upper Platreef located equally near the top of the Critical Zone are in agreement with published ages for the Merensky Reef. Zircon from the deeper-seated Lower Group, Middle Group and Lower Platreef chromitites yields younger concordia ages that may reflect prolonged late-stage volatile activity.

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

High-Ba (~ 11 wt.% BaO) phlogopite was found for the first time in olivinites of the Guli intrusion in the Maimecha–Kotui province of ultrabasic alkaline rocks and carbonatites. The high-Ba mica occurs in assemblage with a paragenesis of olivinite minerals—clinopyroxene, titanomagnetite, apatite, and ilmenite. High-Ba mica is an early phlogopite generation. Its magmatic crystallization led to a decrease in Ba content. Low-Ba mica is a late phlogopite generation. The high Ba/K ratios at the early stages of evolution of a mantle magmatic system are necessary for the formation of high-Ba minerals and point to magma formation at great depths and the contribution of mantle metasomatism to the geochemical characteristics of parental magmas.

Flood basalts are one of the remaining enigmas in global mantle petrology. They come in enormous quantities of up to 10. 6 km. 3 of mantle-derived melt, and they erupt in rather short time intervals of only a few million years. Throughout geological history, all continents have been periodically flooded by dominantly basaltic and rare picritic magmas that can differ widely within the same province in terms of their major element (e.g. high- and low-Ti series), trace element, and radiogenic isotope compositions, suggesting significant compositional heterogeneity within the mantle source regions tapped. In this study of the Late Permian Emeishan large igneous province (ELIP) in SW China picrite lavas from thick stratigraphic successions at Binchuan and Yongsheng represent the low-Ti and high-Ti 'classic' end-members of continental flood basalt magmatism, respectively. This study focuses on the petrochemical variability of the Emeishan magmas, and the genetic links between the suites and their respective mantle sources, based upon estimates of the chemical compositions of the primary melts represented by homogenized melt inclusions hosted by exceptionally primitive olivine (up to 92 mol % Fo in both suites) and Cr-spinel (Cr# 64-72 mol % in Binchuan and 65-80 mol % in Yongsheng) phenocrysts. The average compositions of the melt inclusions and their overall chemical variability, together with the presence of picrites in the province (e.g. Lijiang and Dali localities) with compositions intermediate between the low- and high-Ti end-members, suggest that numerous parental magma batches contributed to a diverse spectrum of more differentiated basaltic magmas within the ELIP. The end-member and intermediate magma compositions are confirmed by the compositions of phenocrysts (Ni and Mn abundances in olivine, Ti abundances in Cr-spinel and clinopyroxene, and trace element abundances in clinopyroxene). The end-member melt and phenocryst compositions (e.g. Gd/Yb in bulk-rocks, melt inclusions and clinopyroxene and Ni-Mn systematics in olivine) suggest a peridotite and garnet pyroxenite mantle source for the low- and high-Ti end-members, respectively. The Sr and Nd isotopic compositions of the two end-member magmas are similar [. 87Sr/. 86Sr. i ∼0·7045; e{open}Nd(t) ∼ +1·7] and are considered to reflect a source in the subcontinental lithospheric mantle rather than the convective asthenosphere or a deep mantle 'plume'. © The Author 2012. Published by Oxford University Press. All rights reserved.

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

Silicate melt inclusions containing rhonite Ca2(Mg,Fe2+)4Fe3+Ti[Al3Si3O20] were studied in olivine phenocrysts from alkali basalts of six different volcanic regions: Udokan Plateau, North Minusa Depression, Tsagan-Khurtei Ridge (Russia), Bakony-Balaton Highland, Nograd-Gomor Region (Hungary) and Makhtesh Ramon (Israel). Rhonite-bearing silicate melt inclusions are relatively common phenomena in alkali basalts and usually coexist with inclusions containing no rhonite. Inclusions with rhonite generally occur in the core of the olivine phenocrysts. According to heating experiments and CO2 microthermometry, all the rhonite-bearing inclusions in core of the olivine phenocrysts were trapped as silicate melt at T > 1300 °C and P > 3–5 kbar. Rhonite crystallized in a narrow temperature range (1180–1260 °C) and P < 0.5 kbar. The petrography and thermometry of rhonite-bearing silicate melt inclusions show a general crystallization sequence: Al-spinel → rhonite → clinopyroxene → apatite → ± amphibole, Fe-Ti oxide (ilmenite or Ti-magnetite) → glass. Majority of rhonites from melt inclusions have Mg/(Mg + Fe2+) > 0.5 and belong to Mg-rich species Ca2Mg4Fe3+Ti[Al3Si3O20]. There are no essential differences in chemistry among rhonites from olivine-hosted silicate melt inclusions from phenocryst, from groundmass of alkali basalts, from alteration products of kaersutitic amphibole mega/xenocrysts and of kaersutite in deep-seated xenoliths in alkali basalts. The rare occurrence of rhonite as essential constituent in rocks may be explained from its microstructural peculiarities. This mineral is an intermediate member of the polysomatic spinel-pyroxene series. Possibly, the structural feature of rhonite does explain why it is an unstable mineral in under changing crystallization conditions. In general, the presence and chemistry of rhonite may be used for rough estimation of temperature, pressure and oxygen fugacity during crystallization of alkali basalts.