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CHEMICAL ENGINEERING (185 journals)                  1 2     

AATCC Journal of Research     Full-text available via subscription   (Followers: 3)
Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials     Hybrid Journal   (Followers: 4)
Acta Polymerica     Hybrid Journal   (Followers: 6)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Advanced Chemical Engineering Research     Open Access   (Followers: 11)
Advanced Powder Technology     Hybrid Journal   (Followers: 16)
Advances in Applied Ceramics     Partially Free   (Followers: 3)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 18)
Advances in Chemical Engineering and Science     Open Access   (Followers: 26)
Advances in Polymer Technology     Hybrid Journal   (Followers: 11)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 5)
Annual Review of Analytical Chemistry     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 10)
Anti-Corrosion Methods and Materials     Hybrid Journal   (Followers: 4)
Applied Petrochemical Research     Open Access   (Followers: 3)
Asia-Pacific Journal of Chemical Engineering     Hybrid Journal   (Followers: 6)
Biochemical Engineering Journal     Hybrid Journal   (Followers: 9)
Biofuel Research Journal     Open Access   (Followers: 3)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 7)
Brazilian Journal of Chemical Engineering     Open Access   (Followers: 3)
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 3)
Carbohydrate Polymers     Hybrid Journal   (Followers: 9)
Catalysts     Open Access   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 7)
Chemical and Materials Engineering     Open Access   (Followers: 1)
Chemical and Petroleum Engineering     Hybrid Journal   (Followers: 12)
Chemical and Process Engineering     Open Access   (Followers: 4)
Chemical and Process Engineering Research     Open Access   (Followers: 6)
Chemical Communications     Full-text available via subscription   (Followers: 34)
Chemical Engineering & Technology     Hybrid Journal   (Followers: 25)
Chemical Engineering and Processing: Process Intensification     Hybrid Journal   (Followers: 10)
Chemical Engineering and Science     Open Access   (Followers: 3)
Chemical Engineering Communications     Hybrid Journal   (Followers: 11)
Chemical Engineering Journal     Hybrid Journal   (Followers: 24)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 19)
Chemical Engineering Research Bulletin     Open Access   (Followers: 1)
Chemical Engineering Science     Hybrid Journal   (Followers: 18)
Chemical Geology     Hybrid Journal   (Followers: 10)
Chemical Papers     Hybrid Journal   (Followers: 3)
Chemical Product and Process Modeling     Hybrid Journal   (Followers: 3)
Chemical Reviews     Full-text available via subscription   (Followers: 205)
Chemical Society Reviews     Full-text available via subscription   (Followers: 36)
Chemical Technology     Open Access   (Followers: 5)
ChemInform     Hybrid Journal   (Followers: 3)
Chemistry & Industry     Hybrid Journal   (Followers: 2)
Chemistry Central Journal     Open Access   (Followers: 5)
Chemistry of Materials     Full-text available via subscription   (Followers: 185)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 7)
ChemSusChem     Hybrid Journal   (Followers: 8)
Chinese Chemical Letters     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemical Engineering     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemical Physics     Hybrid Journal   (Followers: 2)
Coke and Chemistry     Hybrid Journal  
Coloration Technology     Hybrid Journal   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 8)
Computer Aided Chemical Engineering     Full-text available via subscription   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 8)
CORROSION     Full-text available via subscription   (Followers: 17)
Corrosion Engineering, Science and Technology     Hybrid Journal   (Followers: 36)
Corrosion Reviews     Hybrid Journal   (Followers: 5)
Crystal Research and Technology     Hybrid Journal   (Followers: 2)
Current Opinion in Chemical Engineering     Open Access   (Followers: 3)
Education for Chemical Engineers     Hybrid Journal   (Followers: 4)
Eksergi     Open Access  
Emerging Trends in Chemical Engineering     Full-text available via subscription  
European Polymer Journal     Hybrid Journal   (Followers: 44)
Fibers and Polymers     Full-text available via subscription   (Followers: 3)
Fluorescent Materials     Open Access   (Followers: 1)
Focusing on Modern Food Industry     Open Access   (Followers: 3)
Frontiers of Chemical Science and Engineering     Hybrid Journal   (Followers: 1)
Gels     Open Access  
Geochemistry International     Hybrid Journal  
Handbook of Powder Technology     Full-text available via subscription   (Followers: 3)
Heat Exchangers     Open Access   (Followers: 1)
High Performance Polymers     Hybrid Journal  
Indian Chemical Engineer     Hybrid Journal   (Followers: 3)
Indian Journal of Chemical Technology (IJCT)     Open Access   (Followers: 11)
Indonesian Journal of Chemical Science     Open Access  
Industrial & Engineering Chemistry     Full-text available via subscription   (Followers: 10)
Industrial & Engineering Chemistry Research     Full-text available via subscription   (Followers: 20)
Industrial Chemistry Library     Full-text available via subscription   (Followers: 5)
Info Chimie Magazine     Full-text available via subscription   (Followers: 2)
International Journal of Chemical and Petroleum Sciences     Open Access   (Followers: 2)
International Journal of Chemical Engineering     Open Access   (Followers: 7)
International Journal of Chemical Reactor Engineering     Hybrid Journal   (Followers: 3)
International Journal of Chemical Technology     Open Access   (Followers: 4)
International Journal of Chemoinformatics and Chemical Engineering     Full-text available via subscription   (Followers: 2)
International Journal of Food Science     Open Access   (Followers: 4)
International Journal of Industrial Chemistry     Open Access  
International Journal of Polymeric Materials     Hybrid Journal   (Followers: 3)
International Journal of Science and Engineering     Open Access   (Followers: 7)
International Journal of Waste Resources     Open Access   (Followers: 5)
Journal of Chemical Engineering & Process Technology     Open Access   (Followers: 3)
Journal of Applied Crystallography     Hybrid Journal   (Followers: 5)
Journal of Applied Electrochemistry     Hybrid Journal   (Followers: 11)
Journal of Applied Polymer Science     Hybrid Journal   (Followers: 152)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 8)
Journal of Bioprocess Engineering and Biorefinery     Full-text available via subscription  
Journal of Chemical & Engineering Data     Full-text available via subscription   (Followers: 10)

        1 2     

Journal Cover   Geochemistry International
  [SJR: 0.491]   [H-I: 14]   [0 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1556-1968 - ISSN (Online) 0016-7029
   Published by Springer-Verlag Homepage  [2276 journals]
  • A new geochemical perspective on hydrochemical evolution of the Tibetan
           geothermal system
    • Abstract: Abstract The uplift of the Tibetan Plateau has caused the development of many high-enthalpy geothermal fields that are rich in exploitable rare and dispersed resource elements. However, the mechanism of the unusual enrichment of these resource elements is still unclear. From a geochemical viewpoint, including major chemical compositions, some rare and dispersed resource elements and trace elements in geothermal water and some river samples from the northern Lhasa block (saline lake area), the southern Lhasa block (Gangdise volcanic belt) and Tethyan Himalaya in Tibet, this study provides new insights into the mechanism of the hydrochemical evolution of the Tibetan geothermal system. The Cl-type geothermal waters in the Gangdise volcanic belt and Tethyan sedimentary area show similar chemical characteristics that are apparently different from that of surface cold waters. The concentrations of Sb, Tl, As, K, Cs, Li, Rb, Ga, B, Cl, Th, Sc, Mn, V, and Ti in Cl-type geothermal waters are at least one order of magnitude higher than those in surface cold waters, but the concentrations of Ca, Mg, Ni, Cr, Zn, Fe, Co, Cu, Pb, and U in Cl-type geothermal waters are slightly higher or even lower than those in surface cold waters. Some rivers and streams in Tibet also show high concentrations of toxic elements. These rivers and streams are mainly polluted by geothermal spring discharge and are unsuitable for drinking. Some ions and elements (such as Ca, Mg, Ba, Sr, SO 4 2− and Mn) in HCO 3 − —type geothermal waters from sedimentary rocks are affected by the availability of soluble minerals such as calcite, dolomite and gypsum. However, the other dissolved elements in HCO 3 − –type geothermal waters show the characteristic of mixing Cl-type geothermal waters with surface cold waters. The origin of deep fluids in Cl− and HCO 3 − —type springs is related, and this origin probably involves the contribution of crustal partial melting rather than single rock leaching. Thus, deep circulating groundwater mixes with residual magmatic fluids and evolves into the unusual enrichment of geothermal mineral resources.
      PubDate: 2015-12-01
  • Vaporization coefficients of oxides contained in the melts of
           Ca-Al-inclusions in chondrites
    • Abstract: Abstract Based on the analysis of theoretical and experimental data, the following vaporization coefficients are suggested for crystalline oxides contained in Ca-Al-inclusions in chondrites: 0.66 ± 0.15 for CaO, 0.50 ± 0.20 for MgO, 1.00 ± 0.20 for FeO, 0.33 ± 0.02 for Al2O3, 0.23 ± 0.02 for TiO2, and (2.2 ± 0.3) × 10−2 for SiO2. For vaporization from liquids, the coefficients of these oxides found in the Ca-Al-inclusions are equal to one, which is confirmed by the consistency of experimental data and thermodynamic calculations for changes in the composition of multicomponent oxide melts during vaporization.
      PubDate: 2015-12-01
  • Metastable solubilities of mineral SrSO 4 scale in NaCl solution at 298.2
    • PubDate: 2015-12-01
  • Hydrocarbons from a volcanic area. Oil seeps in the Uzon caldera,
    • Abstract: Abstract The isotope and hydrocarbon compositions of oil seeps in the caldera of Uzon Volcano were investigated. An experiment was conducted to simulate the thermal hydrolysis of biota in the hot springs of the caldera, which is considered as a source of carbon for the oil seeps. The same methods were applied to investigate petroleum condensate and thermal gases (CH4 and CO2) from a well in the Bogachevka field adjacent to the Uzon caldera. The measured carbon isotope composition of oils from the Uzon caldera (δ13C of −31.24 and −31.47‰) is typical of oils derived from biological materials of mostly bacterial origin. The low content of tricyclic terpanes, which is a qualitative oil maturity parameter, indicates that the oil maturity of the Uzon seeps is low. In the gas samples, the δ13C of CO2 ranges from −6.5 to −0.18‰ averaging approximately −2.8‰. The δ13C of methane is from −30.13 to −19.03‰ averaging approximately −24.0‰. A difference was detected between the isotopic fractionation characteristics of naphtides from the Uzon caldera and products of the thermal hydrolysis of biota. In turn, the isotopic fractionation characteristic of thermally hydrolyzed biota appeared to be similar to the proportion of the isotopic compositions of the respective fractions of Bogachevka oil. The identical isotopic diagrams of the Bogachevka oil and the hydrothermally transformed biota confirm the biogenic nature of the Bogachevka oil. Hydrocarbons from the Uzon caldera (Kamchatka) are mainly products of the hydrothermal transformation of the biomass of microorganisms and plant remains in the zone of thermal water circulation.
      PubDate: 2015-12-01
  • Species and environmental geochemistry characteristics of organic
           phosphorus in sediments of a riverine wetland measured by 31 P-NMR
    • Abstract: Abstract Phosphorus species in sediment cores obtained from a representative riverine wetland were determined and organic phosphorus was distinguished with phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. The concentrations and distributions of orthophosphate, orthophosphate monoester, orthophosphate diester and pyrophosphate were subsequently characterized. Total phosphorus, total inorganic phosphorus and total organic phosphorus decreased from the top to bottom layer of sediment on the whole. Organic phosphorus was primarily detected in surface sediment layers and scarce toward the bottom, and orthophosphate as a proportion of total organic phosphorus was much higher than other species which was attributed to mineralization as a result of high dissolved oxygen (DO) concentrations. Furthermore, significant positive correlation was observed between alkaline phosphatase activity (APA) and phosphorus fractions suggesting that APA could hydrolyze organic phosphorus into inorganic phosphorus even at high phosphorus concentrations. Significant correlation was also observed between Fe/Al and phosphorus species showed organic phosphorus adsorbed to Fe/Al might be released from sediments and transformed to inorganic phosphorus.
      PubDate: 2015-12-01
  • Geochemistry of Rohtas Limestone from Vindhyan Supergroup, Central India:
           Evidences of detrital input from felsic source
    • Abstract: Abstract The Rohtas Limestone of Semri Group is conformably overlain by Lower Kaimur Group of Vindhyan Supergroup in the Son Valley, Central India. Lower Kaimur Group comprising Sasaram Sandstone, Ghurma Shale and Markundi Sandstone are dominantly quartz arenite in composition. While, Rohtas limestones are micritic carbonates with considerable input of detrital grains/rock fragments. Major oxide data shows that Lower Kaimur sandstone have SiO2 = 92 wt % while limestone exhibit SiO2 = 9.52 wt %, CaO = 47 wt %. Limestones exhibit Sr = 352 ppm, Zr = 20 ppm, while Lower Kaimur sandstones are enriched in Zr = 400 ppm, due to the presence of heavy minerals like zircon. The average limestone and sandstone shows a fractionated LREE pattern and a nearly flat HREE pattern with a small negative Eu anomaly. REE patterns and abundance of limestone are quite similar and comparable to sandstones from Lower Kaimur than to the pure micritic limestone. This indicates that the REE pattern and abundance of Rohtas limestone have been controlled by detrital components possibly derived from the similar source as that for Lower Kaimur sandstones. Apart from the similarity in the REE patterns of limestone and sandstone, the trace element ratios such as Ti/Zr, La/Sc, Th/Sc, Th/Co, Th/U, Zr/Sc, Ba/Sr, La/Th, La/Th, Zr/Hf, [La/Yb]N, [Ce/Yb]N, [Gd/Yb]N, [Sm/Nd]N, [La/Lu]N and Eu/Eu* strongly support the above inference. The ubiquitously comparable REE patterns and incompatible elemental ratios of Rohtas limestones and Lower Kaimur sandstones indicate their derivation from a similar felsic source. The geochemical signatures suggest that the Bundelkhand Gneissic Complex had significantly contributed sediments to the Vindhyan basin prior and during the deposition of Lower Kaimur Group.
      PubDate: 2015-12-01
  • Organic carbon and carbonates in the recent bottom sediments of the Kerch
    • Abstract: Abstract Data on the abundance and distribution of organic carbon and carbonates in the recent bottom sediments of the Kerch Strait were analyzed. It was shown that the content of organic carbon in the bottom sediments of the navigable part of the strait adjacent to the Kerch Peninsula is currently 1.5–2.0 times higher than the values obtained in the 1970s and organic carbon contents in the modern bottom sediments from the part of the strait adjacent to the Taman Peninsula. This is explained by the spatial distribution of the grain-size composition of bottom sediments in the strait and changes in the sedimentation conditions due to anthropogenic activities. As possible environmental consequences of such changes, we discussed the formation of hypoxia zones and increasing risk of asphyxiation phenomena in the strait.
      PubDate: 2015-12-01
  • Geochemical trends of gabbro and granites in the Urals: Evidence of the
           evolutionary history of the mobile belt
    • Abstract: Abstract Principal geochemical features of gabbro and granites in the Urals, the two dominant rock groups of cotectic composition, most adequately reflect the dependences of the composition of the rocks on geological environment, which varied during the evolution of the orogen. The main geochemical trend of the gabbroids is proved to have an age coordinate and was controlled by the progressively more intense metasomatic modification of the mantle wedge as the major source of mafic magmas. The trend reflects the process that can be provisionally defined as “continentalization”. The gabbroids older than 380 Ma tend to plot within the composition field of the oceanic crust (roughly corresponding to N-MORB), whereas younger gabbroids (whose dominant mafic mineral is hornblende) plot within the field of continental mafic rocks. The behavior of such lithophile elements as K and Rb, whose concentrations increase in the course of rock evolution, unambiguously testifies that the trend corresponds to the evolution of the rocks from mafic to acid with time. During the “continentalization” of the mobile belt, the fertility of the magmatic source of the mafic rocks (mantle wedge) increased because of the progressively enhanced metasomatism of the wedge by fluid. Much of this fluid was generated in the subduction zone via the dehydration of hydroxyl-bearing minerals. In the Late Devonian, the dominant source of the fluid was amphibole in amphibolites (metamorphosed basites) and serpentine, and later the relative role of sediments involved in the subduction zone increased. The age trend is almost not reflected in the geochemistry of the granites, and their major geochemical trend can be defined as spatial. The obvious geochemical specifics of the Permian collisional granites in the northwestern and southeastern megablocks were controlled by compositional variations in the source material. Along with the newly-formed crust, the magmatic sources of granites in the northwestern megablock contained much rocks of the Mesoproterozoic granite–gneiss basement, whereas the sources of granites in the southeastern megablock was dominated by orthogneisses, which are metamorphic rocks of Paleozoic gabbro–tonalite–granodiorite–granite series.
      PubDate: 2015-12-01
  • The nature of xenoliths in the Novaya Melovatka intrusion, Voronezh
           Crystalline Massif
    • Abstract: Abstract The paper presents petrographic and petrochemical data on metaterrigenous (comparable with rocks of the Vorontsovka Group) and metamamatic ultramafic–mafic xenoliths in the Paleoproterozoic Novaya Melovatka intrusion in the Voronezh Crystalline Massif (VCM). The intrusion was drilled through by Voronezh Stratigraphic Borehole at Site 3210 of Geotraverse 1-EV. The concordant U-Pb zircon age of a gabbrodiorite xenolith is 2138 ± 25 Ma, and a rock of this age has no analogues among any other magmatic complexes in the geological legend currently adopted for VCM. The younger zircon age value of 2052 ± 22 Ma is thought to be explained by the thermal effect of the Novaya Melovatka intrusion, which was emplaced at 2049 ± 10 to 2057 ± 12 Ma. Xenoliths from this intrusion and from norite of the Elan’ Complex are petrochemically similar to one another and comparable with oceanic-type rocks (cumulus and differentiated mafic–ultramafic series). According to circumstantial evidence, the former were emplaced at relatively shallow depths of 20–30 km in the middle and lower Paleoproterozoic crust, whereas the latter were intruded into the mantle at a depth of 40–50 km, which suggests that the Voronezh block of VCM contains no Archean continental crustal component. The paper reports dada on differences between the Ni-bearing and metallogenically barren mafic–ultramafic massifs.
      PubDate: 2015-12-01
  • Simulation experiments on the generation of organic sulfide in the Shengli
           crude oil
    • Abstract: Abstract Shengli crude oil sample was investigated using a comprehensive method to characterize and identify the formation and distribution of the organic sulfide. A full compositional model uses an autoclave on the system of Shengli crude oil and magnesium sulfate under high temperature and pressure conditions. Gas chromatography (GC) and microcoulometry were used to describe characteristics of gas phase products. The results show that the ratio of methane in the gas composition and the content of hydrogen sulfide improved by increasing temperature, which suggested that with the reaction temperature growing, the extent of the thermochemical sulfate reduction (TSR) process is deepened gradually. With the analysis of oil phase products by fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography-pulsed-flame photometric detector (GC-PFPD), the distribution of organic sulfide can be detected in detail. The contents of organic sulfide especially as mercaptan, sulfoether and thiophene were detected by GC-PFPD. Through FT-ICR MS, sulfide species were characterized by class, type, and carbon number. The results show that, with increasing temperature, the content of mercaptan, became dramatically dominated, sulfoether and thiophene gradually increasing too. Types of sulfur compounds in the oil phase identified by FT-ICR MS are mainly S1, S2, N1S1, O1S1 and O2S1. The S1 species are the most dominated. All of the results suggest that, as the reaction temperature is growing, the evolution process of organic sulfur compounds is originally changed from thiophene series to the benzothiophene series gradually and then to dibenzothiophene series. The products of solid phases were analyzed by FT-IR and XRD. The results show that the content of sulphur in magnesium sulphate decreased. This fenomenon demonstrated transformation of inorganic sulfur compounds into organic sulfur compound. According to the reaction model, the calculated activation energy is 57.91 kJ mol−1 and the frequency factor A is 0.21 s−1.
      PubDate: 2015-12-01
  • Mesozoic–Cenozoic sedimentation in the Circum-Arctic belt. 3:
    • Abstract: Abstract Recent literature data on the Circum-Arctic belt were compiled to revise the global lithological–paleogeographic maps for the Neogene series published by Ronov, Khain, and Balukhovskii in 1989. The Circum-Pacific belt is bounded by the present-day break of continental shelf of the Arctic Ocean in the north and by 60° N latitude in the south. The legend was simplified by removal of climatic and tectonic information, with emphasis placed on mapping the lithofacies zoning. The areas and volumes occupied by sediments of distinguished lithofacies zones and definite rock groups were calculated for each map. Based on these data, the masses of dry sedimentary and volcanic matter, as well as their accumulation rates were determined. The revealed tendencies in the distribution of these quantitative parameters of the Circum-Arctic belt were compared to the corresponding global trends for separate Mesozoic–Cenozoic stages, except for the Quaternary period. The contribution of regional factors was established for sedimentation and magmatism. It was concluded that the sedimentation history in the region was mainly controlled by global tectonic trends and may be subdivided into several stages.
      PubDate: 2015-11-01
  • Redox system of the bottom sediments of the western Kara Sea
    • Abstract: Abstract The geochemical characteristics of bottom sediments from the western Kara Sea, including the estuary of the Ob River and regions outside the zone strongly affected by the river discharge (west of the Yamal Peninsula, Novaya Zemlya Trough, and St. Anna Trough) were considered in the context of reduction–oxidation (redox) processes in seawater, bottom sediments, and pore water. The content of organic matter controls the mechanism and scale of diagenesis, which results in the redistribution of Mn, Fe, and other elements along the sedimentary profile forming redox stratification in the regions of interest. The most significant manifestation of diagenesis in the bottom sediments is the dissolution of reactive Mn and Fe compounds, diffusion in pore water, and formation of an oxidized surface layer varying in thickness from one millimeter to 0.5 m. The appearance of ferromanganese nodules was observed in the oxidized sediments. An ochre-colored oxidized layer often observed in the sedimentary sequence was formed owing to oxygen input by benthic organisms and horizontal water inflow along aquifers connected to the surface or represents a rudimentary unit resulting from nonuniform sedimentation in the past periods. Most of the Kara Sea sediments are reduced and contain iron sulfides, which give gray and black colors to the sediments, and methane, often in cavities. Even the Kara Sea regions farthest from the Ob and Yenisei estuaries exhibit the influence of river discharge on the lithological properties of sediments, OM supply, and biological production. The geological transect from the mouth of the Ob River to the St. Anna Trough is characterized by a zoning typical of the river–sea mixing region in the south and relatively isolated conditions in the north.
      PubDate: 2015-11-01
  • Role of surface phenomena in concentrating incompatible elements: Au in
           pyrite from hydrothermal clays at thermal fields in southern Kamchatka
    • Abstract: Abstract The paper reports data on pyrite obtained using microscopic, physicochemical, and analytical techniques. The major mineral concentrating Au in clays at the Upper Koshelevskoe and East Pauzhetka hydrothermal fields is pyrite, which contains Au evenly distributed in its crystals (0.07–0.25 ppm) and Au bound to the surface of its crystals (0.8–6.8 ppm). The clear correlations between the concentration of equally distributed Au and the topological surface area of single crystals and the absence of correlations with the bulk specific BET surface area rule out purely adsorption mechanisms of Au accommodation at the surface of pyrite crystals, because otherwise the concentration of the minor element would have been proportional to the actual surface area but not the geometric one. In contrast to what is typical of high-temperature hydrothermal systems, at hydrothermal fields Au is an element highly compatible with pyrite. This may be explained by changes in the growth mechanisms of pyrite crystals and the transition to their growth via incorporation of colloid and subcolloid particles. Low-temperature pyrite in hydrothermal clays exhibits certain geochemical features important for exploration for gold deposits related to modern and ancient hydrothermal systems. This pyrite differs from higher temperature pyrite at ancient gold deposits in bearing sulfoxide sulfur species on the surface of its crystals instead of monosulfide species and also in having a less ordered and dense structure, higher porosity, and a globular topography of the surface of crystals.
      PubDate: 2015-11-01
  • Concentrating metals by plants of the genus Salix and their importance for
           identification of Cd anomalies
    • Abstract: Abstract The paper reports data on the specific accumulation of heavy metals by various species of willow (Salix caprea, S. fragili, and S. schwerinii) and other plants of the genus Salix within landscapes with ore anomalies and at background territories: in the area of the Ardon River in North Ossetia, Transbaikalia, and Kamchatka. All willow species can accumulate high concentrations of Cd and sometimes also Zn, and this can serve as a prospecting guide for base-metal and anthropogenic anomalies and be utilized when phytoremediation technologies are developed. The leaves of willow S. caprea that grows in areas contaminated with heavy metals are proved to actively synthesize certain sulfur-bearing phytochelatines.
      PubDate: 2015-11-01
  • Migration of natural radionuclides in surface waters in the El’kon
           uranium mining district, southern Yakutia
    • Abstract: Abstract The paper presents data on the specifics of migration of natural radionuclides with surface waters in anthropogenically contaminated mountain taiga landscapes in the El’kon uranium mining district in southern Yakutia. The radionuclides most intensely leached by the waters of surface watercourses from dumps produced in the course of exploration operations are proved to be 238U and 222Rn. The enrichment of the surface waters in organic matter during the high-water period enhances the migration capability of 238U. Based on the concentrations of these elements analyzed in the waters, bottom sediments, and eluvial soils, estimates are made for the extent of aquatic scatter of natural radionuclides from the contamination sources.
      PubDate: 2015-11-01
  • Modes of Au, Pt, and Pd occurrence in arsenopyrite from the Natalkinskoe
           deposit, NE Russia
    • Abstract: Abstract Pioneering data obtained by studying arsenopyrite from the Natalkinskoe deposit indicate that the mineral contains equidistributed Au, Pt, and Pd in two major non-mineral modes: structural and surface-bound. High Au, Pt, and Pd concentrations in the arsenopyrite are proved to be related to the surface-bound mode. No individual Pt and Pd minerals were detected, while Au occurs mostly in the form of native metal. Variably sized native Au grains (mostly small ones) form aggregates with arsenopyrite and quartz and occur in them as small inclusions. The situation with Pt and Pd is different: arsenopyrite is likely the main concentrator of the elements. Gold-bearing arsenopyrite seems to accommodate all admixtures according to a single mechanism, in which an active role is played by the surface of crystals of the mineral and its surface defects. In view of this, it is possible to recover refractory gold without disintegrating the structure of the mineral, a fact that should be taken into account at, for example, processing ores containing sulfides, for instance, arsenopyrite.
      PubDate: 2015-11-01
  • Radium distribution in anthropogenic soils as a function of soil
           physicochemical and mineralogical parameters
    • Abstract: Abstract We investigated the effects of physicochemical and mineralogical compositions of radioactively contaminated podzolic and soddy–meadow soils on the 226Ra distribution in the soil profile. It was shown that the physicochemical compositions of soils depend on the type of contamination and have different effects on the mobility of the radionuclide. The presence of phosphorus and organic matter was shown to reduce 226Ra mobility. The highest Ra content was observed in the fraction <10 µm. The role of the composition of the fine fraction of the anthropogenic soil was evaluated. Relations between 226Ra and organic matter contents in different size fractions are satisfactorily described by the logarithmic function C Ra = a + bln(C org) (R 2 = 0.9, p < 0.05). The concentrations of 226Ra and organic matter show a positive correlation with relative percentages of illite- and smectite-group minerals and a negative correlation with chlorites.
      PubDate: 2015-11-01
  • Transformation of organic matter in the Holocene sediments of Lake Ochki
           (south Baikal region): Evidence from pyrolysis data
    • Abstract: Abstract Transformation of organic matter (OM) in Holocene sediments of Lake Ochki (southern coast of Lake Baikal) at the early stages of diagenesis has been studied using pyrolytic methods of Rock Eval (RE-pyrolysis) and pyrolysis-gas chromatography-mass spectrometry (Pyr-GC-MS). OM has been analyzed in lacustrine sediments and their main producers, phytoplankton and zooplankton. Data on the distribution of hydrocarbon–biomarkers in sediments indicate an uninterrupted influx of terrigenous OM and transformation of OM precipitated by microorganisms. The analysis of molecular composition of pyrolysates makes it possible to assume a sharp change of sedimentation conditions in the upper part of sedimentary sequence (0–60 cm). It is shown that the macromolecular aliphatic kerogen structure begins to form in incoherent sediment at the very early stages of diagenesis.
      PubDate: 2015-10-01
  • Prediction of the effects of acid mine drainage on variations in the
           hydrogeochemical environment at sulfide-bearing ore deposits
    • Abstract: Abstract Modeling of interactions in the water–rock–CO2–O2 systems was performed for rocks from different sites within a sulfide-bearing ore deposit A. The physicochemical computer modeling showed that acid mine drainage is controlled by the rates of interaction between the components of the system. The reason for the generation of acid mine drainage is that the dissolution rate of aluminosilicate minerals present in the rocks is lower than the rate of sulfide oxidation. The transition from a low to a high water exchange regime resulted in the burst release of pollutants.
      PubDate: 2015-10-01
  • Provenance of “Svecofennian” zircons in the Belomorian mobile
           belt, Baltic shield, and some geodynamic implications
    • Abstract: Abstract The provenance of Archean and Paleoproterozoic zircons in the eclogites and related rocks from the Belomorian Belt of the Baltic Shield is considered on the basis of criteria for their equilibrium with melt, garnet and fluid. It is shown that the Paleoproterozoic zircon with low Th/U ratios (<0.1) and extremely low HREE and MREE contents does not match criteria for its equilibrium crystallization with garnet. This zircon crystallized from Zrand Hf-rich fluid that was in disequilibrium with previously formed eclogite assemblages, but equilibrated with amphibole and plagioclase, thus indicating amphiboliterather than eclogitefacies conditions. The input of fluid and its long-term (~100 Ma) circulation in the deep levels of the Archean juvenile crust of the Belomorian belt was triggered by the Lapland–Kola orogeny. After its peak, the rocks of the belt experienced very slow uplift at rates an order of magnitude lower than those in the Phanerozoic orogens. It is found that Late Archean zircon population contains metamorphic zircon, which matches criteria for simultaneous crystallization with garnet, and oceanic protolithic zircon, which was in equilibrium with high-Mg basalt/gabbro of the Archean oceanic crust. This indicates a subduction origin of the Archean eclogites of the Belomorian belt.
      PubDate: 2015-10-01
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