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  Subjects -> ENGINEERING (Total: 2244 journals)
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CHEMICAL ENGINEERING (187 journals)                     

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AATCC Journal of Research     Full-text available via subscription   (Followers: 3)
ACS Sustainable Chemistry & Engineering     Hybrid Journal  
Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials     Hybrid Journal   (Followers: 4)
Acta Polymerica     Hybrid Journal   (Followers: 7)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Advanced Chemical Engineering Research     Open Access   (Followers: 12)
Advanced Powder Technology     Hybrid Journal   (Followers: 12)
Advances in Applied Ceramics     Hybrid Journal   (Followers: 4)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 21)
Advances in Chemical Engineering and Science     Open Access   (Followers: 33)
Advances in Polymer Technology     Hybrid Journal   (Followers: 12)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
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: 8)
Anti-Corrosion Methods and Materials     Hybrid Journal   (Followers: 5)
Applied Petrochemical Research     Open Access   (Followers: 2)
Asia-Pacific Journal of Chemical Engineering     Hybrid Journal   (Followers: 7)
Biochemical Engineering Journal     Hybrid Journal   (Followers: 12)
Biofuel Research Journal     Open Access   (Followers: 3)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 9)
Brazilian Journal of Chemical Engineering     Open Access   (Followers: 3)
Bulletin of Chemical Reaction Engineering & Catalysis     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 3)
Carbohydrate Polymers     Hybrid Journal   (Followers: 7)
Catalysts     Open Access   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription  
Chemical and Engineering News     Free   (Followers: 10)
Chemical and Materials Engineering     Open Access   (Followers: 3)
Chemical and Petroleum Engineering     Hybrid Journal   (Followers: 9)
Chemical and Process Engineering     Open Access   (Followers: 5)
Chemical and Process Engineering Research     Open Access   (Followers: 7)
Chemical Communications     Full-text available via subscription   (Followers: 62)
Chemical Engineering & Technology     Hybrid Journal   (Followers: 30)
Chemical Engineering and Processing: Process Intensification     Hybrid Journal   (Followers: 14)
Chemical Engineering and Science     Open Access   (Followers: 5)
Chemical Engineering Communications     Hybrid Journal   (Followers: 11)
Chemical Engineering Journal     Hybrid Journal   (Followers: 21)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 20)
Chemical Engineering Research Bulletin     Open Access   (Followers: 2)
Chemical Engineering Science     Hybrid Journal   (Followers: 19)
Chemical Geology     Hybrid Journal   (Followers: 13)
Chemical Papers     Hybrid Journal   (Followers: 2)
Chemical Product and Process Modeling     Hybrid Journal   (Followers: 3)
Chemical Reviews     Full-text available via subscription   (Followers: 127)
Chemical Society Reviews     Full-text available via subscription   (Followers: 38)
Chemical Technology     Open Access   (Followers: 5)
ChemInform     Hybrid Journal   (Followers: 4)
Chemistry & Industry     Hybrid Journal   (Followers: 2)
Chemistry Central Journal     Open Access   (Followers: 5)
Chemistry of Materials     Full-text available via subscription   (Followers: 135)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
ChemSusChem     Hybrid Journal   (Followers: 6)
Chinese Chemical Letters     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemical Engineering     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemical Physics     Hybrid Journal   (Followers: 1)
Coke and Chemistry     Hybrid Journal   (Followers: 1)
Coloration Technology     Hybrid Journal  
Computational Biology and Chemistry     Hybrid Journal   (Followers: 10)
Computer Aided Chemical Engineering     Full-text available via subscription   (Followers: 1)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
CORROSION     Full-text available via subscription   (Followers: 19)
Corrosion Engineering, Science and Technology     Hybrid Journal   (Followers: 35)
Corrosion Reviews     Hybrid Journal   (Followers: 3)
Crystal Research and Technology     Hybrid Journal   (Followers: 5)
Current Opinion in Chemical Engineering     Open Access   (Followers: 4)
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: 40)
Fibers and Polymers     Full-text available via subscription   (Followers: 3)
Fluorescent Materials     Open Access   (Followers: 1)
Focusing on Modern Food Industry     Open Access   (Followers: 2)
Frontiers of Chemical Science and Engineering     Hybrid Journal   (Followers: 1)
Gels     Open Access  
Geochemistry International     Hybrid Journal   (Followers: 2)
Handbook of Powder Technology     Full-text available via subscription   (Followers: 3)
Heat Exchangers     Open Access   (Followers: 1)
High Performance Polymers     Hybrid Journal  
Hungarian Journal of Industry and Chemistry     Open Access  
Indian Chemical Engineer     Hybrid Journal   (Followers: 4)
Indian Journal of Chemical Technology (IJCT)     Open Access   (Followers: 9)
Industrial & Engineering Chemistry     Full-text available via subscription   (Followers: 9)
Industrial & Engineering Chemistry Research     Full-text available via subscription   (Followers: 20)
Industrial Chemistry Library     Full-text available via subscription   (Followers: 3)
Info Chimie Magazine     Full-text available via subscription   (Followers: 3)
International Journal of Chemical and Petroleum Sciences     Open Access   (Followers: 2)
International Journal of Chemical Engineering     Open Access   (Followers: 6)
International Journal of Chemical Reactor Engineering     Hybrid Journal   (Followers: 2)
International Journal of Chemical Technology     Open Access   (Followers: 5)
International Journal of Chemoinformatics and Chemical Engineering     Full-text available via subscription   (Followers: 2)
International Journal of Food Science     Open Access   (Followers: 2)
International Journal of Industrial Chemistry     Open Access  
International Journal of Polymeric Materials     Hybrid Journal   (Followers: 5)
International Journal of Science and Engineering     Open Access   (Followers: 4)
International Journal of Waste Resources     Open Access   (Followers: 3)
Journal of Chemical Engineering & Process Technology     Open Access   (Followers: 4)
Journal of Applied Crystallography     Hybrid Journal   (Followers: 5)
Journal of Applied Electrochemistry     Hybrid Journal   (Followers: 10)
Journal of Applied Polymer Science     Hybrid Journal   (Followers: 102)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Bioprocess Engineering and Biorefinery     Full-text available via subscription  
Journal of Chemical & Engineering Data     Full-text available via subscription   (Followers: 10)
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Ecology     Hybrid Journal   (Followers: 5)
Journal of Chemical Engineering     Open Access   (Followers: 6)
Journal of Chemical Engineering and Materials Science     Open Access   (Followers: 1)
Journal of Chemical Science and Technology     Open Access   (Followers: 4)
Journal of Chemical Sciences     Partially Free   (Followers: 17)
Journal of Chemical Technology & Biotechnology     Hybrid Journal   (Followers: 10)
Journal of Chemical Theory and Computation     Full-text available via subscription   (Followers: 13)
Journal of CO2 Utilization     Hybrid Journal   (Followers: 1)
Journal of Coatings     Open Access   (Followers: 4)
Journal of Crystallization Process and Technology     Open Access   (Followers: 6)
Journal of Environmental Chemical Engineering     Hybrid Journal   (Followers: 3)
Journal of Food Measurement and Characterization     Hybrid Journal  
Journal of Food Processing & Technology     Open Access  
Journal of Fuel Chemistry and Technology     Full-text available via subscription   (Followers: 4)
Journal of Fuels     Open Access  
Journal of Geochemical Exploration     Hybrid Journal  
Journal of Industrial and Engineering Chemistry     Hybrid Journal   (Followers: 1)
Journal of Information Display     Hybrid Journal  
Journal of Inorganic and Organometallic Polymers and Materials     Partially Free   (Followers: 6)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 5)
Journal of Non-Crystalline Solids     Hybrid Journal   (Followers: 7)
Journal of Ocean University of China (English Edition)     Hybrid Journal  
Journal of Organic Semiconductors     Open Access   (Followers: 4)
Journal of Physics and Chemistry of Solids     Hybrid Journal   (Followers: 5)
Journal of Polymer and Biopolymer Physics Chemistry     Open Access   (Followers: 4)
Journal of Polymer Engineering     Hybrid Journal   (Followers: 8)
Journal of Polymer Research     Hybrid Journal   (Followers: 6)
Journal of Polymer Science Part C : Polymer Letters     Hybrid Journal   (Followers: 5)
Journal of Polymers     Open Access   (Followers: 2)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Journal of Powder Technology     Open Access   (Followers: 1)
Journal of Pure and Applied Chemistry Research     Open Access   (Followers: 1)
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 223)
Journal of the Bangladesh Chemical Society     Open Access  
Journal of the Brazilian Chemical Society     Open Access   (Followers: 2)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal   (Followers: 1)
Journal of the Pakistan Institute of Chemical Engineers     Open Access   (Followers: 1)
Journal of the Taiwan Institute of Chemical Engineers     Hybrid Journal   (Followers: 2)
Journal of Water Chemistry and Technology     Hybrid Journal   (Followers: 8)
Jurnal Inovasi Pendidikan Kimia     Open Access  
Jurnal Reaktor     Open Access  
Jurnal Teknologi Dan Industri Pangan     Open Access   (Followers: 1)
Korean Journal of Chemical Engineering     Hybrid Journal   (Followers: 3)
Main Group Metal Chemistry     Hybrid Journal   (Followers: 1)
Materials Chemistry and Physics     Full-text available via subscription   (Followers: 14)
Materials Science and Applied Chemistry     Open Access  
Materials Sciences and Applied Chemistry     Full-text available via subscription  
Molecular Imprinting     Open Access  
MRS Communications     Hybrid Journal  
Nanocontainers     Open Access  
Nanofabrication     Open Access  
Noise Control Engineering Journal     Full-text available via subscription   (Followers: 2)
Ochrona Srodowiska i Zasobów Naturalnych : Environmental Protection and Natural Resources     Open Access  
Petroleum Chemistry     Hybrid Journal   (Followers: 1)
Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B     Full-text available via subscription   (Followers: 3)
Plasma Processes and Polymers     Hybrid Journal  
Plasmas and Polymers     Hybrid Journal  
Polymer     Hybrid Journal   (Followers: 83)
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Composites     Hybrid Journal   (Followers: 13)
Powder Technology     Hybrid Journal   (Followers: 12)
Recyclable Catalysis     Open Access   (Followers: 1)
Research on Chemical Intermediates     Hybrid Journal  
Reviews in Chemical Engineering     Hybrid Journal   (Followers: 5)
Revista Cubana de Química     Open Access  
Revista ION     Open Access  
Revista Mexicana de Ingeniería Química     Open Access  
Rubber Chemistry and Technology     Full-text available via subscription   (Followers: 2)
Russian Chemical Bulletin     Hybrid Journal   (Followers: 2)
Russian Journal of Applied Chemistry     Hybrid Journal   (Followers: 1)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 54)
Solid Fuel Chemistry     Hybrid Journal  
South African Journal of Chemical Engineering     Open Access   (Followers: 2)
South African Journal of Chemistry     Full-text available via subscription   (Followers: 2)
Surface Engineering and Applied Electrochemistry     Hybrid Journal   (Followers: 5)
Sustainable Chemical Processes     Open Access   (Followers: 1)
Synthesis Lectures on Chemical Engineering and Biochemical Engineering     Full-text available via subscription  
The Canadian Journal of Chemical Engineering     Hybrid Journal   (Followers: 3)
The Chemical Record     Hybrid Journal   (Followers: 1)
Theoretical Foundations of Chemical Engineering     Hybrid Journal   (Followers: 2)
Transition Metal Chemistry     Hybrid Journal   (Followers: 2)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Visegrad Journal on Bioeconomy and Sustainable Development     Open Access   (Followers: 1)
Zeitschrift für Naturforschung B : A Journal of Chemical Sciences     Open Access   (Followers: 1)

           

Journal Cover Geochemistry International
  [SJR: 0.491]   [H-I: 14]   [2 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  [2281 journals]
  • Test of the Ballhaus–Berry–Green Ol–Opx–Sp
           oxybarometer and calibration of a new equation for estimating the redox
           state of melts saturated with olivine and spinel
    • Abstract: Abstract Testing the Ballhaus–Berry–Green Ol–Opx–Sp oxybarometer (BBG) on independent experimental data indicates that it overestimates the oxygen fugacity by 0.6–1.3 log units under mildly reduced conditions (near the C–CO buffer) and by as much as 2–3 log units under reduced conditions (at the IW buffer and below it). A newly developed oxibarometer is suggested to minimize this effect and enhance the capabilities of redoxometry of low-pressure mineral associations, including magmatic melts undersaturated with respect to orthopyroxene (Opx). The new empirical equation of the oxybarometer is applicable to a wide range of mafic–ultramafic magmas of normal alkalinity, including terrestrial, lunar, and meteoritic systems under pressures of 0.001–25 kbar and oxygen fugacity ranging from IW–3 to NNO + 1. The derived regression fits the ΔQFM values of the calibration dataset (154 experiments) accurate to ~0.5 log units. The new oxybarometer eliminates systematic errors when redox parameters are evaluated for the reduced region (from IW–3 to C–CO) and for crystallization of magmas without Opx on the liquidus. The efficiency of the suggested model is demonstrated by its application to natural rocks: (1) low-Ti lunar basalts, (2) tholeiites from the Shatsky Rise, (3) Siberian flood basalts, (4) rocks of the layered series of the Yoko-Dovyren intrusion, and (5) mantle xenoliths collected in southern Siberia, Mongolia, China, and the southern Russian Far East. The values yielded by such oxybarometers for intrusive rocks, which underwent long-lasting cooling and postcumulus reequilibration, should be regarded with reserve.
      PubDate: 2016-04-01
       
  • Low-temperature heat capacity and thermodynamic properties of PrPO 4
    • Abstract: Abstract The heat capacity of praseodymium orthophosphate PrPO4 was measured by adiabatic and relaxation calorimetric techniques at 5.12–345.54 K, and these data were utilized to calculate thermodynamic functions of PrPO4 at 6–350 K. The Gibbs free energy of PrPO4 formation Δ f G 0(298.15 K) is evaluated at 1851.8 ± 4.7 kJ mol–1.
      PubDate: 2016-04-01
       
  • Ore sources of the base-metal veins at the Dzhimidon deposit, North
           Ossetia, Russia: Evidence from REE distribution in ores and host rocks
    • Abstract: Abstract REE distribution patterns of the ores and host rocks of the Dzhimidon vein lead-zinc deposit (North Caucasus, Ossetia, Sadon mining district, Russia) have been analyzed to estimate ore sources of hydrothermal deposits. It is established that both types of prevailing rocks of the Sadon Area are involved in the formation of base-metal ores during activation of hydrothermal metasomatic processes in the Jurassic time, the said rocks are Paleozoic granites (the main ore-hosting rocks at the majority of deposits) and Pre- Cambrian schists (specific for only ore-hosting rocks of Dzhimidon deposit).
      PubDate: 2016-04-01
       
  • Comparison of petrology and isotope geochemistry of the Bulka
           peridotite–gabbro massif and granitoids of the Kyzykchadra complex
           (West Sayan)
    • Abstract: Abstract The study provides new petrologic and isotope geochemical data for rocks of the 465 ± 5 Ma Bulka massif (Borodina et al., 2011). The primary amphibole from granitoid stocks cutting across the layered series of the massif yielded an Ar–Ar age of 415.9 ± 3.7 Ma. The rocks of the Bulka massif have 143Nd/144Nd ratio of 0.513243 and εNd (Т) values of +12.00. The granitoids have 143Nd/144Nd ratios between 0.512919 and 0.512961 and εNd (Т) values between +8.03 and +9.25. The Nd isotope composition indicates that the rocks of the Bulka massif and granitoids were derived from a depleted mantle source. Depletion of the rocks of the massif in LILE, LREE, and HFSE over LILE is inherited from the mantle source, which has geochemical signatures of N-MORB and subduction-related components. Granitoids are metaluminous I-type granites, which were probably generated either by differentiation of intermediate to mafic mantle-derived magmas or by melting of metabasites. The rocks of the granitoid stocks are characterized by enrichment in LILE and LREE and depletion in HFSE over LILE, which suggests derivation from arc-related parental magmas.
      PubDate: 2016-04-01
       
  • Key processes determining secondary alterations in kimberlites
    • Abstract: Abstract A variety of hypotheses have been put forward as to the nature of secondary alteration. They were tested by using the amount of insoluble SiO2 accumulated in the rocks (Q) as the index of secondary alteration degree. This parameter allows any sample to be characterized with the degree of its secondary alteration. By putting Q values together with contents of CaO and rare earth elements, features of diamond crystal size distributions within samples in most altered kimberlites, and the distribution of these parameters over kimberlite bodies, we show that secondary processes occurred when kimberlites were exposed to postmagmatic solutions: fluids containing water and carbon dioxide. Endogenous fluids rose from the bottom of pipes along narrow local zones and spread beyond them at the top, involving larger rock masses. There, they mingled with vadose and phreatic water. The basicity decreased abruptly, inducing profound changes of rock-forming minerals and alteration of diamond crystal weight distribution by recrystallization. The study invokes a great body of factual information, including hundreds and thousands of analyzes of kimberlites from Yakutian diamond pipes: Botuobinskaya, Nyur’inskaya, Maiskaya, Internatsional’naya, Mir, Aikhal, Yubileinaya, Sytykanskaya, Udachnaya-West, and Udachnaya-East.
      PubDate: 2016-04-01
       
  • Silver and silver microparticles of the Cretaceous-Paleogene boundary
           sediment of Fish Clay Højerup (Stevns Klint, Denmark)
    • Abstract: Abstract We report the occurrence of micrometer-sized silver particles in the red (“impact” or “ejecta”) layer of the Fish Clay. These appear to be embedded into the biogenic/abiogenic calcite matrix. Energy dispersive X-ray analysis indicates that these microparticles are composed of pure silver (>99% of the total weight). Scanning electron microscopy images reveal irregular and predominantly rounded shapes with rugged surfaces. Numerous silver microparticles are spherical, and some exhibit dendritic textures. These microparticles were probably originated during the Chicxulub asteroid impact event, or immediately afterwards, and dispersed globally.
      PubDate: 2016-04-01
       
  • Ninetyeast ridge: Magmatism and geodynamics
    • Abstract: Abstract The study of magmatism and tectonic structure of the East Indian or Ninetyeast Ridge (NER) reveals the geochemical similarity of mantle sources for the NER and Kerguelen Plateau melts. Magmas related to the Kerguelen plume were derived from an enriched mantle source, whereas the NER tholeiitic basalts originated from a source contaminated by a depleted material. While, depleted basalt varieties were not found within the NER basalts. It was shown that magmatic rocks forming the NER were generated by high degrees (30%) of partial melting within the ancient Wharton spreading ridge due to the activity of the Kerguelen plume, which was located at this time in the vicinity of the ridge. The most significant impact of the plume on the NER structures was recorded at 70–50 Ma ago.
      PubDate: 2016-03-01
       
  • Physicochemical parameters of crystallization differentiation and
           Fe–Ti ore-forming processes in the magmatic system of the
           Elet’ozero massif (Northern Karelia)
    • Abstract: Abstract The rocks of the Elet’ozero intrusion are characterized by high relative abundances of incompatible elements, with (La/Lu) N varying from 2.1 to 36.6, and a distinct positive Ba anomaly, which may record crystallization of Ba minerals during the formation of mafic rocks. The anomalous Ba enrichment is probably associated with a large-scale fluid-mediated mass transfer during subduction of a lithospheric slab within the Karelian craton which was synchronous with the generation of magmas parental to the Elet’ozero pluton. The presence of Al-rich spinel in gabbroic rocks as early-formed magmatic phases suggests crystallization at relatively high pressures (~0.5 GPa or ~15 km depth). The oxygen fugacity changed with time during the evolution of the magmatic system, approaching its maximum values (approximately 1.5 log units above the quartz–fayalite–magnetite buffer) during extensive crystallization of Fe–Тi oxides. High oxygen fugacities, Ti enrichment of mafic rocks, and lack of any positive correlation between Mg-numbers and Ni content in olivine can be useful indicators of potentially mineralized mafic intrusions.
      PubDate: 2016-03-01
       
  • Rare earth elements in the ore-bearing sediments of the Krasnov and
           Semenov hydrothermal fields, Mid-Atlantic Ridge
    • PubDate: 2016-03-01
       
  • Comparative analysis of pelagic Pleistocene silica accumulation in the
           Pacific and Indian Oceans
    • Abstract: Abstract The methodical principles of the analysis of biogenic silica accumulation in the pelagic zones of the Pacific and Indian oceans are considered. Two quantitative approaches of lithological analysis are compared: method of absolute mass by A.D. Arkhangel’skii and volumetric method by A.B. Ronov. It is established that the concept of “two oceans” (“ice” and “non-ice”) may be applied to both the oceans. Differences in the evolution of the silica accumulation rate in the Pleistocene between high- and low-latitude oceans are revealed.
      PubDate: 2016-03-01
       
  • Experimental study of the system Au–UO 2 –TiO 2 –aqueous
           fluid at 500°C and 1 kbar. 1. Synthesis of brannerite
    • PubDate: 2016-03-01
       
  • Heterogeneity of grain-size fractions of nanodiamonds from the Orgueil C1
           meteorite
    • Abstract: Abstract A model for the composition of meteoritic nanodiamonds is suggested based on analysis of the concentrations and isotopic compositions of C, N, and Xe in the nanodiamond-rich grain-size fractions, which were separated for the first time from the Orgueil CI chondrite. According to the model, meteoritic nanodiamond consists of two populations of grains (denoted CHL and CN). The size distributions of grains in populations in the CHL and CN populations are different: the CHL population is finer grained than CN. The grains of the CHL population are characterized by a radial gradient in the carbon isotopic composition, and they contain implanted anomalous noble gases (HL component) and the heavy nitrogen isotope 15N. Following (Clayton et al., 1995), the probable astrophysical source of this population of nanodiamond grains is thought to be the mixing helium and hydrogen shells of a Type-II supernova, and the mechanism that produced these grains was the slow CVD process. The CN population grains have homogeneous isotopic compositions of carbon (δ13C ≡–100‰) and nitrogen (δ15N ≡–400‰) and contain almost all nitrogen of the nanodiamond-rich fractions. This population of nanodiamond grains was likely formed by a fast unequilibrated process, when shock waves affected organic compounds or gas rich in C- and N-bearing compounds during the early evolution of the protosolar nebula. Calculations within the framework of the model show that the nanodiamond-rich fractions separated from the Orgueil meteorite have the CN/CHL ratios varying from 1 in the finest grained fraction to 10 in the coarse-grained one. At these proportions of the populations, weighted mean δ13C values of CHL grains in the fractions lie within the range of 42 to 394‰, and the concentrations of 132Xe-HL and 15N are (49–563) × 10–8 cm3/gC and (1.1–6.2) × 10–5 cm3/gC, respectively.
      PubDate: 2016-03-01
       
  • Dualistic distribution coefficients of trace elements in the system
           mineral–hydrothermal solution. III. precious metals (Au and Pd) in
           magnetite and manganmagnetite
    • Abstract: Abstract Distribution coefficients D of Au and Pd between magnetite (manganmagnetite) and ammonium chloride hydrothermal solution and the structural D str and surface-related D sur terms of these coefficients were determined at 450 and 500°С and a pressure of 1 kbar using internal sampling techniques. Quantitative data on the speciation of precious metals are obtained using the technique of statistical selections of analytical data on single crystals SSADSC and compared with LA-ICP-MS data. Both Pd and Au are elements compatible with magnetite and its manganoan variety: D str is ≈3 for Pd and ≈1 for Au, although Au seems to weakly enrich fluid at 500°C: D str ≈ 0.5–0.8. The trends of postmagmatic Pd and Au fractionation can thus strongly depend on the presence of spinel-group minerals, first of all, magnetite and its solid solutions. The dualistic nature of the distribution coefficients provides sound grounds to believe that both elements are highly compatible, with regard not only for the structural but also for the surface-related modes of their occurrence (D sur ≈ 17 and ≈50–70 for Au and Pd, respectively). The maximum concentrations of structural modes of the elements are 5.3 ppm for Au and 5.1 ppm for Pd and were found in the solid solution whose jacobsite mole fractions were 0.82 and 0.49, respectively. The principal distribution patterns of the elements in crystals are confirmed by LA-ICP-MS data. Data on this system testify that the distribution coefficients of minor and trace elements are geochemically dualistic because of the abnormal absorption properties of nanometer-sized nonautonomous phases on the surface of ore minerals, and this dualism plays an important geochemical role.
      PubDate: 2016-02-01
       
  • A new injection technique of microquantity of water from fluid inclusions
           into mass spectrometer for measurement of hydrogen and oxygen isotope
           compositions
    • PubDate: 2016-02-01
       
  • Eclogites in the Chara zone, NE Kazakhstan: New geochemical and
           geochronological data
    • PubDate: 2016-02-01
       
  • Geochemistry, petrogenesis and age of metamorphic rocks of the Angara
           complex at the junction of South and North Yenisei Ridge
    • Abstract: Abstract The mineralogical, petrological, geochemical and geochronological data were used to evaluate the age and petrogenesis of compositionally contrasting metamorphic rocks at the junction between Meso-Neoproterozoic Transangarian structures and Archean-Paleoproterozoic complexes of the Angara–Kan inlier of the Yenisei Ridge. The studied metabasites and metapelites provide clues for understanding the evolution of the region. The magmatic protoliths of low-Ti metabasites were derived by melting of depleted (N-MORB) upper mantle, and their high-Ti counterparts are interpreted to have originated from an enriched mantle source (E-MORB). The petrogeochemical characteristics of protoliths of the metabasite dikes resemble those of within-plate basalts and ocean island tholeiites. The Fe- and Al-rich metapelites are redeposited and metamorphosed products of Precambrian weathering crusts of kaolinite and montmorillonite-chlorite-hydromica compositions. The Р–Т conditions of metamorphism (4.9–5.5 kbar/570–650°С for metabasites; 4.1–7.1 kbar/500–630°С for metapelites) correspond to epidote–amphibolite to amphibolite facies transition. The evolution of the Angara complex occurred in two stages. The early stage (1.18–0.85 Ga) is associated with Grenville tectonics and the late stage is correlated with accretion/collision episodes of the Valhalla orogeny, with the peaks at 810–790 and 730–720 Ma, and the final stage of the Neoproterozoic evolution of the orogen on the southwestern margin of the Siberian craton. The correlation of regional crustal processes with globalscale geological events in the Precambrian evolution of the Earth supports recent paleomagnetic reconstructions that allow a direct, long-lived (1400–600 Ma) spatial and temporal connection between Siberia, Laurentia, and Baltica, which have been parts of ancient supercontinents.
      PubDate: 2016-02-01
       
  • Mineral composition of tephra layers in the Quaternary deposits of the Sea
           of Okhotsk:: Heavy minerals associations and their geochemistry
    • Abstract: Abstract Heavy mineral associations from tephra layers in the Quaternary deposits of the Sea of Okhotsk and their chemical characteristics were studied by various techniques. It was shown that such investigations may have a bearing on the problems of tephrostratigraphic correlation. We assessed the possibility of application of the mineral composition of distal tephra for identification and, in particular, estimation of the relation of tephras to the explosive volcanism of back-arc and frontal zones of island arcs. The investigation of the compositions of minerals and use of mineral geothermometers and geobarometers (two-pyroxene, magnetite–ilmenite, and amphibole) provided evidence on the physicochemical parameters of melt crystallization during the explosive volcanic eruptions that produced the distal tephra layers. It was established that the pyroclastic material of some tephra layers was supplied during explosive eruptions not only from shallow magma chambers but also from deeper and higher temperature reservoirs. Together with the geochemical signatures of volcanic glasses, the obtained results on mineral associations and the geochemistry of mineral inclusions are applicable for the comparative analysis and correlation of tephras from marine and continental sequences, as well as for the identification of explosive volcanic products in adjacent land areas.
      PubDate: 2016-02-01
       
  • New approaches to studying heavy metals in soils by X-ray absorption
           spectroscopy (XANES)) and extractive fractionation
    • Abstract: Abstract A comprehensive approach to studying the nature of interaction between heavy-metal ions and the organic–mineral matrix of soils involves application of modern physical analytical techniques and chemical methods of extractive fractionation. XANES was used to obtain the first data on the near-edge fine structure of X-ray spectra for a number of heavy-metal species in ordinary chernozem. Data on the structure of soil samples saturated with Zn2+ and Cu2+ obtained by XANES (X-ray absorption near-edge structure) make it possible to elucidate the interaction mechanisms of the metals and the types of chemical bonds formed thereby. As contamination doze of with Cu and Zn is increased (from 2000 to 10 000 mg/kg soil), particularly if the metals are introduced in the form of readily solubility salts, bonding between the metals and soil components weakens. Data of extractive fractionation of metal compounds from samples saturated with Cu and Zn compounds testify that the Cu2+ ion is preferably retained in the organic matter of the soil, whereas the Zn2+ ion is bound mostly to silicates, carbonates, and Fe and Mn (hydro)oxides.
      PubDate: 2016-02-01
       
  • Geochemistry of fractionation of coherent elements (Zr and Hf) during the
           profound differentiation of peralkaline magmatic systems: A case study of
           the Lovozero Complex
    • Abstract: Abstract The paper presents pioneering data on Hf distribution in peralkaline rocks, ores, and rock-forming and accessory minerals of the Lovozero Complex. Variations in the Zr/Hf ratio are determined in all rocks of the Lovozero alkaline massif. This ratio is proved to increase in the course of evolution of alkaline magma because of fractionation of alkaline pyroxene. The Hf distribution coefficient is evaluated for alkali-rich pyroxene, whose crystallization controls Zr and Hf fractionation during the differentiation of alkaline magma. These data and the equation of equilibrium and fractional crystallization are utilized in a model suggested for Zr and Hf fractionation in the course of evolution of the Lovozero intrusion.
      PubDate: 2016-01-01
       
  • Long-term galactic cosmic ray variations over the last billion years based
           on the cosmic-ray exposure ages of iron meteorites
    • Abstract: Abstract The distribution of the cosmic-ray exposure ages (T) of iron meteorites was analyzed to establish the possible variations in the intensity of the galactic cosmic ray (GCR) over the last billion years. The analysis was made for the entire data set containing ~80 age values from the literature (Voshage et al., 1983) and the corrected set after the exclusions of paired meteorites (using the Akaike information criterion). The dependence of the criterion χ2 in the distribution of the phase values Ph = T/t–int(T/t) on the values of the assumed period (t) of GCR variations was analyzed for both sets of meteorites. The significant deviations of these parameters from the respective average values were found for t ~ 400–500 Myr and, in part, for t ~ 150 Myr. These deviations were interpreted by numerical modeling using the values of ages randomly distributed in the range of 0–1000 Ma. It was found that for variations with a period of 450 Myr, the distribution of the phase values and cosmic-ray exposure ages in the model data set is similar to that of iron meteorites. These results testify to the existence of the GCR variations with a period of ~400–500 Myr during the last 1 Gyr. The variations in the GCR flux can be explained by periodic galactic spiral arm crossings of the solar system. The GCR variations with a period of ~150 Myr discussed in the previous studies (Shaviv, 2002; 2003; Scherer et al., 2006) appears to be less certain.
      PubDate: 2016-01-01
       
 
 
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