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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.

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.

An augmented reality display based on a planar waveguide made in photo-thermo-refractive glass had been demonstrated. The monolithic integration of multiplexed volume Bragg gratings with the waveguide platform provided in/out-coupling and image transmission from a portable projector. Design and calculation of the grating configuration was performed. The optical replication method was simulated and implemented for manufacturing the multiplexed coupling elements. Resulted field of view was limited by the projection system of the prototype, however can be expanded beyond 50o.

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.

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.

In this paper it was carried out the numerical simulation of the main working parameters (light current- voltage curves, quantum yield spectral distributions) of SnS-based (SnS/SnS2/ITO, SnS/ZnS/ITO) solar cells (SCs) using the SCAPS-3102 simulation package. Using the basis input simulation parameters such as wide band gap Eg,, layers thicknesses d, electron affinities х, etc. there were estimated the next SCs characteristics: open-circuit voltages UOC, short-circuit current densities JSC, fill-factors FF and their efficiencies ᶯ . These data allows us to estimate the optimal constructive parameters of simulated SCs. В даній роботі проведене числове моделювання основних експлуатаційних характеристик (світлові вольт-амперні характеристики, спектральні розподіли квантової ефективності) сонячних елементів (СЕ), виконаних на базі шару SnS (SnS/SnS2/ITO, SnS/ZnS/ITO) з використанням програмного пакету SCAPS-3102. Обравши такі базові характеристики для моделювання, як ширина забороненої зони Eg,, товщини шарів d, спорідненості електронів х, тощо, були отримані наступні експлуатаційні характеристики СЕ: напруга холостого ходу UOC, густина струму короткого замикання JSC, фактор заповнення FF та коефіцієнт корисної дії фотоперетворення ᶯ. Отримані значення дозволили визначити оптимальні конструктивні параметри змодельованих сонячних елементів. В данной работе было проведено численное моделирование основных эксплуатационных характеристик (световые вольт-амперные характеристики, спектральное распределения квантовой эффективности) солнечных элементов (СЭ), исполненных на основе слоя SnS (SnS/SnS2/ITO, SnS/ZnS/ITO) с использованием программного пакета SCAPS-3102. Избрав такие характеристики для моделирования, как ширина запрещенной зоны Eg,, толщины слоев d, электронное сродство х, и т.д., были получены следующие эксплуатационные характеристики СЭ: напряжение холостого хода UOC, плотность тока короткого замыкания JSC, фактор заполнения FF и коэффициент полезного действия фотопреоб- разования ᶯ. Полученные значения позволили определить оптимальные конструктивные параметры смоделированных солнечных элементов.

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.

The paper deals with Russian geographical terms in the Karelian dialects of Tver Region and is mainly based on field materials collected by the author in the 2000s. The author argues that the main corpus of geographical terms and place names of the studied area is of Karelian origin and correlates with geographical terminology and toponymy of other groups of the Karelian population that migrated in the past from the north-eastern Lake Onega Region. At the same time, as distinct from other areas of settlement of the Karelian population, the dialects of Tver Karelians are rich in loan words from the Russian language which appeared in different periods: a part of them represent traditional geographical terms of the Russian population of Tver Region, while others seem to be relatively recent innovations, mainly of the Soviet period. According to the data provided by the author, approximately 40 % of current geographical terms of the Karelian dialects of Tver region are of Russian origin. This proportion can be explained by the specificity of the landscape of the studied territory which differs from the landscape of the original Karelian areas, as well as by Tver Karelians' long habitation in the Central Russian Historical Zone which made permanent contacts with the Russian population inevitable.

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.

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.

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

Homogeneity of a peridotitic garnet inclusion in diamond demonstrating excess in Si concentration (i.e. presence of majorite component) was investigated by TEM using FIB prepared foils. The host diamond is a low-nitrogen brown stone, which can be related to type IIa with features of strong plastic deformation. The studied sample is represented by Ca-poor Cr-pyrope of harzburgitic (H) paragenesis from Snap Lake dyke, Canada The garnet had been previously reported to contain Si = 3.16 apfu. The revised examination of the sample, resulted in detection of extremely fine-grained symplectite consisting of low Ca-orthopyroxene, clinopyroxene, Cr-spinel and coesite completely located and isolated in the inner part of the garnet crystal, which forms a sharp interface with the surrounding homogeneous garnet. XRD study confirmed the presence of the minerals constituting the symplectite. EPMA showed an identical bulk chemistry of the nanometer-sized symplectite and garnet. Further polishing of the garnet inclusion on the same surface with diamond removed the symplectite, which possibly was present as a thin lens within garnet. The remaining garnet is completely homogeneous as checked by two profiles, and contains unusually high Ni (118.2 ppm) and depleted REE patterns. Estimated PT formation conditions of this garnet are 10.8 GPa and 1450 °C within asthenosphere. Symplectite testifies partial retrograde isochemical phase transformation of the examined garnet which is suggested to be caused by decompression along with plastic deformation of diamond within the coesite stability field at T > 1000 °C and depth no less than 100 km. Because previously published studies of rare majoritic garnets composition were performed by EPMA only, it is possible that the traces of partial phase transformation (symplectite formation) could have been overlooked without additional XRD and/or TEM/AEM studies.

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

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

Relative to the CI chondrite class of meteorites (widely thought to be the 'building blocks' of the terrestrial planets), the Earth is depleted in volatile elements. For most elements this depletion is thought to be a solar nebular signature, as chondrites show depletions qualitatively similar to that of the Earth. On the other hand, as lead is a volatile element, some Pb may also have been lost after accretion. The unique (206)Pb/(204)Pb and (207)Pb/(204)Pb ratios of the Earth's mantle suggest that some lead was lost about 50 to 130 Myr after Solar System formation. This has commonly been explained by lead lost via the segregation of a sulphide melt to the Earth's core, which assumes that lead has an affinity towards sulphide. Some models, however, have reconciled the Earth's lead deficit with volatilization. Whichever model is preferred, the broad coincidence of U-Pb model ages with the age of the Moon suggests that lead loss may be related to the Moon-forming impact. Here we report partitioning experiments in metal-sulphide-silicate systems. We show that lead is neither siderophile nor chalcophile enough to explain the high U/Pb ratio of the Earth's mantle as being a result of lead pumping to the core. The Earth may have accreted from initially volatile-depleted material, some lead may have been lost to degassing following the Moon-forming giant impact, or a hidden reservoir exists in the deep mantle with lead isotope compositions complementary to upper-mantle values; it is unlikely though that the missing lead resides in the core.

The geochemistry of mineral inclusions in diamonds is an important source of information on the composition of continental lithospheric mantle at depths exceeding 120-150 km. At these depths two main types of geological environment support diamond formation: they are ultramafic (or peridotitic) (U-type) and eclogitic (E-type) environments as shown by minerals that occur as inclusions in diamonds and compose xenoliths of diamondiferous peridotites and eclogites in kimberlites. In primary, diamond-bearing kimberlite and lamproite rocks the ratio of diamonds from these two geological environments varies widely between localities. However, U-type diamonds dominate in the overwhelming majority of diamond occurrences worldwide. Olivine is the most typical inclusion in U-type diamonds and coexists both as touching or non touching inclusions with enstatite, pyrope, chromite in harzburgitic or dunitic (without enstatite) assemblages and Cr-rich diopside (lherzolitic and wehrlitic assem- blages). More than 260 olivine inclusions sometimes associated with enstatite, Cr-rich diopside, pyrope and chromite were studied from diamonds of major Siberian mines, including Aikhal, Yubileinaya, Internatsionalnaya, Komsomolskaya, Sytykanskaya and alluvials from the north-eastern part of the Siberian Craton. Most olivine inclusions were prepared for analysis on a single polished surface with diamond. Olivine from diamonds of the Snap Lake dyke system (Canada) were studied for comparison. The olivine composition in eight xenoliths of diamondiferous peridotites from Udachnaya pipe, representing the rarest mantle samples, was also re-examined. Inclusions were analyzed for major and minor elements with an electron microprobe so as to obtain high precision and accuracy, especially for Ni, Ca, Mn, Cr, Co and Al. Minor-element abundances of the overwhelming majority of analyzed olivine vary within the following ranges in wt.% (NiO 0.320-0.408; CaO 0.005-0.045; MnO 0.079-0.131; Cr2O3 0.013-0.115; CoO 0.009-0.022 and Al2O3 0.007-0.039). About 70 % of all studied olivines demonstrate very low CaO (< 0.02 wt.%), which reflects a relatively low temperature of equilibration for the lherzolitic paragenesis, or lack of clinopyroxene associated with olivine. Some olivines of anomalous composition are detected in microdiamonds only. They contain relatively low forsterite (Fo) (100 Mg/(Mg+Fe)) along with very low MnO and unusually high NiO (86.6-90.0; 0.063-0.076 wt.% and 0.461-0.556 wt.%, respectively). The grain of such composition located in the inner diamond growth zone is associated with an olivine grain of "normal" composition in the outer zone of one microdiamond sample. Such a difference in olivine compositions may indicate an enrichment of the diamond growing source in garnet at the initial stages of diamond growth. The high-precision approach to trace elements by electron probe opens new possibilities for more accurate estimation of olivine assemblages, the temperature and pressure of diamond formation, and identification of clearly anomalous olivine compositions which may represent a crustal signature.

Olivine is the principal mineral of kimberlite magmas, and is the main contributor to the ultramafic composition of kimberlite rocks. Olivine is partly or completely altered in common kimberlites, and thus unavailable for studies of the origin and evolution of kimberlite magmas. The masking effects of alteration, common in kimberlites worldwide, are overcome in this study of the exceptionally fresh diamondiferous kimberlites of the Udachnaya-East pipe from the DaldynAlakit province, Yakutia, northern Siberia. These serpentine-free kimberlites contain large amounts of olivine (similar to 50 vol.%) in a chloridecarbonate groundmass. Olivine is represented by two populations (olivine-I and groundmass olivine-II) differing in morphology, colour and grain size, and trapped mineral and melt inclusions. The large fragmental olivine-I is compositionally variable in terms of major (Fo(8594)) and trace element concentrations, including H2O content (10-136 ppm). Multiple sources of olivine-I, such as convecting and lithospheric mantle, are suggested. The groundmass olivine-II is recognized by smaller grain sizes and perfect crystallographic shapes that indicate crystallization during magma ascent and emplacement. However, a simple crystallization history for olivine-II is complicated by complex zoning in terms of Fo values and trace element contents. The cores of olivine-II are compositionally similar to olivine-I, which suggests a genetic link between these two types of olivine. Olivine-I and olivine-II have oxygen isotope values ( +5.6+/- 0.1 parts per thousand VSMOW, 1 SD) that are indistinguishable from one another, but higher than values (+5.18 +/- 0.28 parts per thousand) in typical mantle olivine. These elevated values probably reflect equilibrium with the Udachnaya carbonate melt at low temperatures and O-18-enriched mantle source. The volumetrically significant rims of olivine-II have constant Fo values (89.0 +/- 0.2 mol%), but variable trace element compositions. The uniform Fo compositions of the rims imply an absence of fractionation of the melts Fe2+/Mg, which is possible in the carbonatite meltolivine system. The kimberlite melt is argued to have originated in the mantle as a chloridecarbonate liquid, devoid of ultramafic or basaltic aluminosilicate components, but became olivine-laden and olivine-saturated by scavenging olivine crystals from the pathway rocks and dissolving them en route to the surface. During emplacement the kimberlite magma changed progressively towards an original alkali-rich chloridecarbonate melt by extensively crystallizing groundmass olivine and gravitational separation of solids in the pipe.

The oxygen fugacity f(O2)of the Earth's mantle is one of the fundamental variables in mantle petrology. Through ferric-ferrous iron and carbon-hydrogen-oxygen equilibria, f(O2) influences the pressure-temperature positions of mantle solidi and compositions of small-degree mantle melts. Among other parameters, f(O2) affects the water storage capacity and rheology of the mantle. The uppermost mantle, as represented by samples and partial melts, is sufficiently oxidized to sustain volatiles, such as H2O and CO2, as well as carbonatitic melts, but it is not known whether the shallow mantle is representative of the entire upper mantle. Using high-pressure experiments, we show here that large parts of the asthenosphere are likely to be metal-saturated. We found that pyroxene and garnet synthesized at >7 GPa in equilibrium with metallic Fe can incorporate sufficient ferric iron that the mantle at >250 km depth is so reduced that an (Fe,Ni)-metal phase may be stable. Our results indicate that the oxidized nature of the upper mantle can no longer be regarded as being representative for the Earth's upper mantle as a whole and instead that oxidation is a shallow phenomenon restricted to an upper veneer only about 250 km in thickness.

To test whether the silicate reference glasses BAM-S005-A and BAM-S005-B from BAM (The Federal Institute for Materials Research and Testing, Germany) are suitable materials for microanalysis, we investigated the homogeneity of these reference glasses using the microanalytical techniques EPMA, LA-ICP-MS and SIMS. Our study indicated that all major and most trace elements are homogeneously distributed at micrometre sampling scale in both types of glass. However, some trace elements (e.g., Cs, Cl, Cr, Mo and Ni) seem to be inhomogeneously distributed. We also determined the composition of BAM-S005-A and BAM-S005-B. The EPMA data of major elements confirmed the information values specified by the certificate. With the exception of Sr, Ba, Ce and Pb, our trace element data by LA-ICP-MS were also in agreement with the certified values within the stated uncertainty limits. The reasons for the discrepancy in these four elements are still unclear. In addition, we report new data for twenty-two further trace elements, for which the concentrations were not certified. Based on our investigation, we suggest that both of these materials are suitable for many microanalytical applications. Afin de tester si les verres silicates de reference BAM-S005-A et BAM-S005-B provenant du BAM (Institut federal de recherche et d’essais sur les materiaux, Allemagne) sont des materiaux appropries pour la microanalyse, nous avons etudie l’homogeneite de ces verres de reference en utilisant les techniques de microanalyse EPMA, LA-ICP-MS et SIMS. Notre etude a revele que tous les elements majeurs et la plupart des elements traces sont repartis de facon homogene dans les deux types de verre a l’echelle micrometrique d’echantillonnage. Toutefois, certains elements traces (par exemple, Cs, Cl, Cr, Mo et Ni) semblent etre distribues de facon inhomogene. Nous avons egalement determine les compositions de BAM-S005-A et BAM-S005-B. Les donnees EPMA des elements majeurs ont confirme les valeurs specifiees par le certificat. A l’exception du Sr, Ba, Ce et Pb, nos donnees d’elements traces par LA-ICP-MS sont egalement en accord avec les valeurs certifiees dans les limites d’incertitude indiquees. Les raisons des ecarts observes pour ces quatre elements sont encore mal connues. En outre, nous presentons de nouvelles donnees pour vingt-deux elements traces supplementaires, pour lesquels les concentrations n’ont pas ete certifiees. Sur la base de notre etude, nous suggerons que ces deux materiaux sont adaptes pour de nombreuses applications de microanalyse.

International audience; Large igneous provinces (LIPs) are known for their rapid production of enormous volumes of magma (up to several million cubic kilometres in less than a million years)1, for marked thinning of the lithosphere2,3, often ending with a continental break-up, and for their links to global environmental catastrophes4,5. Despite the importance of LIPs, controversy surrounds even the basic idea that they form through melting in the heads of thermal mantle plumes2,3,6,7,8,9,10. The Permo-Triassic Siberian Traps11--the type example and the largest continental LIP1,12--is located on thick cratonic lithosphere1,12 and was synchronous with the largest known mass-extinction event1. However, there is no evidence of pre-magmatic uplift or of a large lithospheric stretching7, as predicted above a plume head2,6,9. Moreover, estimates of magmatic CO2 degassing from the Siberian Traps are considered insufficient to trigger climatic crises13,14,15, leading to the hypothesis that the release of thermogenic gases from the sediment pile caused the mass extinction15,16. Here we present petrological evidence for a large amount (15 wt%) of dense recycled oceanic crust in the head of the plume and develop a thermomechanical model that predicts no pre-magmatic uplift and requires no lithospheric extension. The model implies extensive plume melting and heterogeneous erosion of the thick cratonic lithosphere over the course of a few hundred thousand years. The model suggests that massive degassing of CO2 and HCl, mostly from the recycled crust in the plume head, could alone trigger a mass extinction and predicts it happening before the main volcanic phase, in agreement with stratigraphic and geochronological data for the Siberian Traps and other LIPs5.

We present new reference values for the NIST SRM 610–617 glasses following ISO guidelines and the International Association of Geoanalysts’ protocol. Uncertainties at the 95% confidence level (CL) have been determined for bulk- and micro-analytical purposes. In contrast to former compilation procedures, this approach delivers data that consider present-day requirements of data quality. New analytical data and the nearly complete data set of the GeoReM database were used for this study. Data quality was checked by the application of the Horwitz function and by a careful investigation of analytical procedures. We have determined quantitatively possible element inhomogeneities using different test portion masses of 1, 0.1 and 0.02 μg. Although avoiding the rim region of the glass wafers, we found moderate inhomogeneities of several chalcophile/siderophile elements and gross inhomogeneities of Ni, Se, Pd and Pt at small test portion masses. The extent of inhomogeneity was included in the determination of uncertainties. While the new reference values agree with the NIST certified values with the one exception of Mn in SRM 610, they typically differ by as much as 10% from the Pearce et al. (1997) values in current use. In a few cases (P, S, Cl, Ta, Re) the discrepancies are even higher. Nous presentons des nouvelles valeurs de reference pour les verres NIST SRM 610–617 en suivant les recommandations de l’ISO et le protocole de l’IAG. Les incertitudes au niveau de confiance de 95% ont ete determinees a des fins d’analyse totale et de micro-analyse. Contrairement aux procedures de compilation precedentes, cette approche fournit des donnees qui tiennent compte des exigences actuelles dans la qualite des donnees. De nouvelles donnees analytiques et le jeu de donnees presque complet de la base de donnees GeoReM ont ete utilises pour cette etude. La qualite des donnees a ete verifiee par l’application de la fonction de Horwitz et par un examen minutieux des procedures analytiques. Nous avons determine quantitativement les possibles inhomogeneites d’element en utilisant des prises d’essai de masses differentes correspondant a 1, 0.1 et 0.02 μg. Bien que nous ayons evite les zones de bordure des disques de verre, nous avons trouve des inhomogeneites moderees pour plusieurs elements chalcophiles/siderophiles et des inhomogeneites flagrantes de Ni, Se, Pd et Pt pour les prises d’essai de petites masses. La mesure d’inhomogeneite a ete incluse dans la determination des incertitudes. Alors que les nouvelles valeurs de reference sont en accord avec les valeurs NIST certifiees a la seule exception du Mn dans SRM 610, elles sont generalement differentes, avec des ecarts de pres de 10%, des valeurs de Pearce et al. (1997) qui sont d’un usage courant. Dans quelques cas (P, S, Cl, Ta, Re), les ecarts sont encore plus eleves.

Sobolev et al. show that highly radiogenic strontium in melt inclusions from lavas of the Mauna Loa shield volcano in Hawaii have an isotopic composition matching that of sea water aged 200 million to 650 million years old. They infer that such sea water must have contaminated the Mauna Loa source rock prior to subduction, imparting a unique 'time stamp' and indicating that mantle circulation has an average speed of about 2 centimetres per year, which is more rapid than previously thought. Recycling of oceanic crust through subduction, mantle upwelling, and remelting in mantle plumes is a widely accepted mechanism to explain ocean island volcanism1. The timescale of this recycling is important to our understanding of mantle circulation rates. Correlations of uranogenic lead isotopes in lavas from ocean islands such as Hawaii or Iceland, when interpreted as model isochrons, have yielded source differentiation ages between 1 and 2.5 billion years (Gyr)2,3,4,5. However, if such correlations are produced by mixing of unrelated mantle components6 they will have no direct age significance. Re–Os decay model ages take into account the mixing of sources with different histories7,8, but they depend on the assumed initial Re/Os ratio of the subducted crust, which is poorly constrained because of the high mobility of rhenium during subduction9. Here we report the first data on 87Sr/86Sr ratios for 138 melt inclusions in olivine phenocrysts from lavas of Mauna Loa shield volcano, Hawaii, indicating enormous mantle source heterogeneity. We show that highly radiogenic strontium in severely rubidium-depleted melt inclusions matches the isotopic composition of 200–650-Myr-old sea water. We infer that such sea water must have contaminated the Mauna Loa source rock, before subduction, imparting a unique ‘time stamp’ on this source. Small amounts of seawater-derived strontium in plume sources may be common but can be identified clearly only in ultra-depleted melts originating from generally highly (incompatible-element) depleted source components. The presence of 200–650-Myr-old oceanic crust in the source of Hawaiian lavas implies a timescale of general mantle circulation with an average rate of about 2 (±1) cm yr−1, much faster than previously thought.

Here we combine petrological-geochemical and thermomechanical modeling techniques to explain origin of primary magmas of both Maimecha–Kotui meimechites and the Gudchikhinskaya basalts of Norilsk region, which represent, respectively, the end and the beginning of flood magmatism in the Siberian Trap Province. We have analyzed the least altered samples of meimechites, their olivine phenocrysts, and melt inclusions in olivines, as well as samples of dunites and their olivines, from boreholes G-1 and G-3 within the Guli volcanoplutonic complex in the Maimecha–Kotui igneous province of the northern Siberian platform. The Mn/Fe and Ni/MgO ratios in olivines indicate a mantle peridotite source of meimechites. Meimechite parental magma that rose to shallow depths was rich in alkalis and highly magnesian (24 wt.% MgO), largely degassed, undersaturated by sulfide liquid and oxidized. At greater depths, it was, likely, high in CO2 (6 wt.%) and H2O (2 wt.%) and resulted from partial melting of initially highly depleted and later metasomatized harzburgite some 200 km below the surface. Trace-element abundances in primary meimechite magma suggest presence of garnet and K-clinopyroxene, in the mantle source and imply for genetic link to the sources of the early Siberian flood basalts (Gudchikhinskaya suite) and kimberlites. The analyzed dunite samples from the Guli complex have chemistry and mineralogy indicating their close relation to meimechites. We have also computed thermomechanical model of interaction of a hot mantle plume with the shield lithosphere of variable thickness, using realistic temperature- and stress-dependent visco-elasto-plastic rocks rheology and advanced finite element solution technique. Based on our experimental and modeling results we propose that a Permian–Triassic plume, with potential temperature of about 1650 °C transported a large amount of recycled ancient oceanic crust (up to 15%) as SiO2-oversaturated carbonated eclogite. Low-degree partial melting of eclogite at depths of 250–300 km produced carbonate-silicate melt that metasomatized the lithospheric roots of the Siberian shield. Further rise of the plume under relatively attenuated lithosphere (Norilsk area) led to progressive melting of eclogite and formation of reaction pyroxenite, which then melted at depths of 130–180 km. Consequantly, a large volume of melt (Gudchikhinskaya suite) penetrated into the lithosphere and caused its destabilization and delamination. Delaminated lithosphere that included fragments of locally metasomatized depleted harzburgite subsided into the plume and was heated to the temperatures of the plume interior with subsequent generation of meimechite magma. Meimechites showed up at the surface only under thicker part of the lithosphere aside from major melting zone above because otherwise they were mixed up in more voluminous flood basalts. We further suggest that meimechites, uncontaminated Siberian flood basalts and kimberlites all share the same source of strongly incompatible elements, the carbonated recycled oceanic crust carried up by hot mantle plume.

Recycled subducted ocean crust has been traced by elevated 187Os/188Os in some studies and by high nickel and low manganese contents in others. Here, we show that these tracers are linked for Quaternary lavas of Iceland, strengthening the recycling model. An estimate of the osmium isotopic composition of both the recycled crust and the mantle peridotite implies that Icelandic Quaternary lavas are derived in part from an ancient crustal component with model ages between 1.1 × 10 9 and 1.8 × 10 9 years and from a peridotitic end-member close to present-day oceanic mantle.

The volcanic hazard potential of Mount Etna volcano is currently nourished by long-lasting, powerful eruptions of basaltic magmas coupled with increased seismicity and ground deformation, and the world's largest discharge of volcanic gases. The current evolutionary cycle of Mount Etna activity is consistent with subduction-related chemical modifications of the mantle source. Arrival of a new mantle-derived magma batch beneath the volcano has been hypothesized, but is still elusive among the erupted products. Here we demonstrate petrological and geochemical affinities between the magmas supplying modern eruptions and high-Mg, fall-stratified (FS) basalts ejected violently similar to 4 k.y. ago. The FS primitive magmas (similar to 13 wt% MgO) are characteristically volatile enriched (at least 3.8 wt% H2O and 3300 ppm CO2), and bear a trace element signature of a garnet-bearing, metasomatized source (high Gd/Yb, K/La, U/Nb, Pb/Ce, Ca/Al). They started crystallizing olivine (Fo(91)), clinopyroxene (Mg# 92.5), and Cr spinel deep in the plumbing system (> 5 kbar), contributing to the cumulate piles at depth and to differentiated alkaline basalt and trachybasalt magmas in the shallow conduit. Continuous influx of mantle-derived, volatile-rich magmas, such as those that supplied the FS fallout, provides a good explanation for major compositional and eruptive features of Mount Etna.

The role of recycled material in mantle plumes is difficult to quantify on the basis of incompatible trace elements and isotopes because of the great variability of subducted material. Another approach is to use major elements and compatible trace elements because these are more uniform in the mantle and are strongly controlled by the phase petrology of melting. Subducted crustal lithologies invariably differ from mantle peridotite, and this introduces olivine-free lithologies such as pyroxenites and eclogites into the mantle. Our massive study of olivine phenocrysts and trapped melt inclusions shows unusually high Ni and Si contents in many recent primary Hawaiian magmas. Similar compositions are found in the Canary Islands, W. Greenland, and the Siberian flood basalts. These magmas are not in equilibrium with an olivine bearing source under thick lithosphere (more than 100 km) typical of these localities, because an olivine-pyroxene assemblage would buffer both Ni and Si at lower levels. In contrast, magmas from plumes located under thin lithosphere, such as Iceland or Azores show no significant Si and Ni excess, and they could be in equilibrium with a shallow, olivine-bearing source. High-Si magmas can be produced by melting of eclogite, but this does not yield high Ni contents. Therefore, the eclogite-derived melt must acquire high Ni by converting surrounding peridotite to a solid pyroxenite, which ultimately melts a shallower level. Because unreacted peridotite may also begin to melt at shallow depths, this results in mixed melts derived from (secondary) pyroxenite and peridotite. In settings of thick lithosphere, the amount of peridotite-derived melt will be relatively small. Therefore, the recycled component represented by pyroxenite-derived melt may dominate. In settings of shallow melting, the peridotite will melt more extensively, and the signal from the recycled component will be diluted. Quantitative modeling shows that over half of the Hawaiian magma volume formed during the last 1 Myr came from secondary pyroxenite representing the recycled oceanic crust. The results are consistent with a plume with potential temperature of 1600 deg.C containing about 20 percent of recycled oceanic crust in the central part. These results are also consistent with estimates of volcano volumes, magma volume flux, and seismological observations. In the context of this model, the recent increase in Hawaiian magma flux is produced by an unusually high proportion of recycled crustal material in this part of the plume.