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CHEMISTRY (614 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 13)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 42)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 20)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 20)
ACS Macro Letters     Full-text available via subscription   (Followers: 25)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 40)
ACS Nano     Full-text available via subscription   (Followers: 265)
ACS Photonics     Full-text available via subscription   (Followers: 13)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 23)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chimica Slovenica     Open Access  
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 6)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 8)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 54)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 65)
Advances in Chemical Science     Open Access   (Followers: 16)
Advances in Chemistry     Open Access   (Followers: 20)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19)
Advances in Drug Research     Full-text available via subscription   (Followers: 21)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 25)
Advances in Nanoparticles     Open Access   (Followers: 15)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 43)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 3)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 61)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 15)
American Journal of Chemistry     Open Access   (Followers: 29)
American Journal of Plant Physiology     Open Access   (Followers: 11)
American Mineralogist     Hybrid Journal   (Followers: 15)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 164)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 236)
Annales UMCS, Chemia     Open Access  
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 5)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 8)
Applied Spectroscopy     Full-text available via subscription   (Followers: 22)
Applied Surface Science     Hybrid Journal   (Followers: 31)
Arabian Journal of Chemistry     Open Access   (Followers: 5)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 337)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 20)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 119)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 84)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 2)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 71)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 9)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 18)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 73)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 26)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 22)
Chemical Reviews     Full-text available via subscription   (Followers: 181)
Chemical Science     Open Access   (Followers: 23)
Chemical Technology     Open Access   (Followers: 22)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 7)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 56)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 32)
Chemistry & Industry     Hybrid Journal   (Followers: 6)
Chemistry - A European Journal     Hybrid Journal   (Followers: 151)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 20)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Materials     Full-text available via subscription   (Followers: 245)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 19)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 4)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 11)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 11)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 6)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 11)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 5)
Combustion Science and Technology     Hybrid Journal   (Followers: 22)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 3)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal  
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 70)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  

        1 2 3 4 | Last

Journal Cover American Mineralogist
  [SJR: 1.185]   [H-I: 104]   [15 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0003-004X
   Published by GeoScienceWorld Homepage  [14 journals]
  • A Mössbauer-based XANES calibration for hydrous basalt glasses reveals
           radiation-induced oxidation of Fe
    • Authors: Cottrell E; Lanzirotti A, Mysen B, et al.
      Abstract: Oxygen fugacity (fO2) exerts first-order control on the geochemical evolution of planetary interiors, and the Fe3+/∑Fe ratios of silicate glasses provide a useful proxy for fO2. Fe K-edge micro-X-ray absorption near-edge structure (XANES) spectroscopy allows researchers to micro-analytically determine the Fe3+/∑Fe ratios of silicate glasses with high precision. In this study we characterize hydrous and anhydrous basalt glass standards with Mössbauer and XANES spectroscopy and show that synchrotron radiation causes progressive changes to the XANES spectra of hydrous glasses as a function of radiation dose (here defined as total photons delivered per square micrometer), water concentration, and initial Fe3+/∑Fe ratio.We report experiments from eight different radiation dose conditions and show that Fe in hydrous silicate glasses can undergo rapid oxidation upon exposure to radiation. The rate and degree of oxidation correlates with radiation dose and the product of water concentration and ferrous/ferric iron oxide ratio on a molar basis (Φ = XHO0.5·XFeO/XFeO1.5). For example, a basalt glass with 4.9 wt% dissolved H2O and Fe3+/∑Fe = 0.19 from its Mössbauer spectrum may appear to have Fe3+/∑Fe ≥ 0.35 when analyzed over several minutes at a nominal flux density of ∼2 × 109 photons/s/μm2. This radiation-induced increase in Fe3+/∑Fe ratio would lead to overestimation of fO2 by about two orders of magnitude, with dramatic consequences for the interpretation of geological processes.The sample area exposed to radiation shows measureable hydrogen loss, consistent with radiation-induced breaking of O–H bonds, associated H migration and loss, and oxidation of Fe2+. This mechanism is consistent with the observation that anhydrous glasses show no damage under any beam conditions. Cryogenic cooling does not mitigate, but rather accelerates, iron oxidation. The effects of beam damage appear to persist indefinitely.We detect beam damage at the lowest photon flux densities tested (3 × 106 photons/s/μm2); however, at flux densities ≤6 × 107 photons/s/μm2, the hydrous glass calibration curve defined by the centroid (derived from XANES spectra) and Fe3+/∑Fe ratios (derived from Mössbauer spectra) is indistinguishable from the anhydrous calibration curve within the accuracy achievable with Mössbauer spectroscopy. Thus, published Fe3+/∑Fe ratios from hydrous glasses measured at low photon flux densities are likely to be accurate within measurement uncertainty with respect to what would have been measured by Mössbauer spectroscopy.These new results demonstrate that to obtain accurate Fe3+/∑Fe ratios from hydrous, mafic, silicate glasses, it is first necessary to carefully monitor changes in the XANES spectra as a function of incident dose (e.g., fixed-energy scan). Defocusing and attenuating the beam may prevent significant oxidation of Fe in mafic water-bearing glasses.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Craters of the Moon National Monument basalts as unshocked compositional
           and weathering analogs for martian rocks and meteorites
    • Authors: Adcock CT; Udry A, Hausrath EM, et al.
      Abstract: The availability of terrestrial sites that are martian analogs allows researchers to investigate Mars using knowledge gained on Earth. Among the terrestrial analog sites for Mars is Craters of the Moon National Monument (COTM) in Idaho, U.S.A. Craters of the Moon National Monument is home to over 60 basalt lava flows, many of which have been dated from 2050 to 18 340 years before present (y.b.p.). Following previous authors, we examined the chemistry and petrogenesis of COTM basalts compared to basaltic martian rocks, martian meteorites, and meteorite clasts, and then examined the results of chemical weathering of the basaltic flows. Results of our comparative chemical analysis suggest COTM basalts are generally more evolved than the martian materials, with a few notable exceptions. Several COTM flow basalts, including rocks of the >18 000 year old Kimama flow, have high FeO, TiO2, and P2O5 contents similar to the Wishstone and Watchtower class rocks analyzed at Gusev Crater, Mars, by the Mars Exploration Rover Spirit. The youngest basalts of COTM, such as those of the Minidoka (3890 y.b.p.) and Blue Dragon (2050 y.b.p.) flows have similarities in SiO2, alkali contents, and mineralogical norms with select clasts in meteorite Northwest Africa (NWA) 7034. These similarities over a range of flow ages therefore suggest that COTM basalts have the potential to shed important light on specific igneous processes occurring on Mars.Many of the basaltic rocks measured by rovers on Mars are thought to have experienced chemical weathering during aqueous interactions; however, few basalt weathering rates exist for terrestrial Mars-relevant field environments to help interpret these processes. COTM, which has important similarities to some martian rocks discussed above, also represents a basalt flow chronosequence, and therefore allows for the investigation of basalt weathering as a function of time. We measured the depth of developed porosity in a suite of basalt flows ranging from 2050 to 18 340 y.b.p., and compared field weathering relationships at COTM to weathering rinds developed on the Gusev Crater martian rocks Humphrey, Champagne, Mazatzal, and Wooly Patch. Our results indicate that depths of incipient weathering in COTM rocks increase with time at a rate of 2.32 × 10−2 to 3.04 × 10−2 μm/yr, which is comparable to other terrestrial advance rates. Interestingly, this rate also indicates that chemical weathering strongly outpaces physical weathering even in this arid to semi arid environment. Weathering primarily of the matrix glass indicates that glass may be functioning as the profile-controlling mineral, which may have implications for chemical weathering in glass-rich rocks on Mars. Weathering rates of glass and other minerals can also help constrain the conditions (pH, temperature) of alteration on Mars. Of the altered martian rocks we compared to COTM (Humphrey, Champagne, Mazatzal, and Wooly Patch), altered surfaces of Mazatzal rock at Gusev Crater show the most similarities to weathered surfaces at COTM. Comparisons of chemical weathering in COTM basalts with altered surfaces of rocks in Gusev Crater, Mars, indicate Gusev Crater martian rocks have undergone significantly more aqueous alteration than that experienced by basaltic flows at COTM.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Characterizing the source of potentially asbestos-bearing commercial
           vermiculite insulation using in situ IR spectroscopy
    • Authors: Swayze GA; Lowers HA, Benzel WM, et al.
      Abstract: Commercially produced vermiculite insulation from Libby, Montana, contains trace levels of asbestiform amphibole, which is known to cause asbestos-related diseases. When vermiculite insulation is found in a building, evaluation for its potential asbestos content traditionally involves collecting a sample from an attic or wall and submitting it for time-consuming analyses at an off-site laboratory. The goal of this study was to determine if in situ near-infrared reflectance measurements could be used to reliably identify the source of vermiculite ore and therefore its potential to contain asbestos. Spectra of 52 expanded ore samples, including attic insulation, commercial packing materials, and horticultural products from Libby, Montana; Louisa, Virginia; Enoree, South Carolina; Palabora, South Africa; and Jiangsu, China, were measured with a portable spectrometer. The mine sources for these vermiculite ores were identified based on collection location, when known, and on differences in elemental composition as measured by electron probe microanalysis. Reflectance spectra of the insulation samples show vibrational overtone and combination absorptions that vary in wavelength position and relative intensity depending on elemental composition and proportions of their constituent micas (i.e., vermiculite ore usually consists of a mixture of hydrobiotite and vermiculite mineral flakes). Band depth ratios of the 1.38/2.32, 1.40/1.42, and 2.24/2.38 μm absorptions allow determination of a vermiculite insulation's source and detection of its potential to contain amphibole, talc, and/or serpentine impurities. Spectroscopy cannot distinguish asbestiform vs. non-asbestiform amphiboles. However, if the spectrally determined mica composition and mineralogy of an insulation sample is consistent with ore from Libby, then it is likely that some portion of the sodic-calcic amphibole it contains is asbestiform, given that all of the nearly two dozen Libby vermiculite insulation samples examined with scanning electron microscopy in this study contain amphiboles. One sample of expanded vermiculite ore from multiple sources was recognized as a limitation of the spectral method, therefore an additional test (i.e., 2.24 μm absorption position vs. 2.24/2.38 μm band depth ratio) was incorporated into the spectral method to eliminate misclassification caused by such mixtures. With portable field spectrometers, the methodology developed can be used to determine vermiculite insulation's source and estimate its potential amphibole content, thereby providing low-cost analysis with onsite reporting to property owners.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Nanocrystalline apatites: The fundamental role of water
    • Authors: Drouet C; Aufray M, Rollin-Martinet S, et al.
      Abstract: Bone is a natural nanocomposite. Its mineral component is nanocrystalline calcium phosphate apatite, whose synthetic biomimetic analogs can be prepared by wet chemistry. The initially formed crystals, whether biological or synthetic, exhibit very peculiar physicochemical features. In particular, they are nanocrystalline, nonstoichiometric, and hydrated. The surface of the nanocrystals is covered by a non-apatitic hydrated layer containing mobile ions, which may explain their exceptional surface reactivity. For their precipitation in vivo or in vitro, for their evolution in solution, for the 3D organization of the nanocrystals, and for their consolidation to obtain bulk ceramic materials, water appears to be a central component that has not received much attention. In this mini-review, we explore these key roles of water on the basis of physicochemical and thermodynamic data obtained by complementary tools including FTIR, XRD, ion titrations, oxide melt solution calorimetry, and cryo-FEG-SEM. We also report new data obtained by DSC, aiming to explore the types of water molecules associated with the nanocrystals. These data support the existence of two main types of water molecules associated with the nanocrystals, with different characteristics and probably different roles and functions. These findings improve our understanding of the behavior of bioinspired apatite-based systems for biomedicine and also of biomineralization processes taking place in vivo, at present and in the geologic past. This paper is thus intended to give an overview of the specificities of apatite nanocrystals and their close relationship with water.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • New petrological, geochemical, and geochronological perspectives on
           andesite-dacite magma genesis at Ruapehu volcano, New Zealand
    • Authors: Conway CE; Gamble JA, Wilson CN, et al.
      Abstract: Time–composition relationships in eruptive sequences at composite volcanoes can show how the ongoing intrusion of magmas progressively affects the lithosphere at continental convergent margins. Here, new whole-rock and microanalytical major and trace element data from andesite-dacite lava flows are integrated with previous studies and existing isotopic data, and placed within the framework of a high-resolution chronostratigraphy for Ruapehu volcano (southern Taupo Volcanic Zone, New Zealand). The geochemical evolution of lavas erupted over the ∼200 kyr lifetime of the exposed edifice reflects variable degrees of fractionation and systematic changes in the type of crustal assimilation in the Ruapehu magma system. Lavas erupted from ∼200–150 ka have previously been distinguished from those erupted <150 ka based on Sr-Nd isotopic characteristics, which indicate that the oldest lavas were sourced from magmas that assimilated oceanic crust. Such source rocks underlie the regionally widespread Mesozoic meta-sedimentary greywacke-argillite basement, which was conversely assimilated by <150 ka magmas. New results from this work reveal that since 150 ka, an upper limit of magma differentiation occurred from ∼50–35 ka. High K2O (∼6 wt%) and Rb contents (∼270 ppm) in melt inclusions, interstitial glass, and glass from in situ quenched melts of partially fused crustal xenoliths are reported for andesite-dacite lavas erupted during this period. In addition to crystal fractionation, selective partial melting and assimilation of K- and Rb-rich mineral phases (e.g., biotite, K-feldspar) that are significant components of the meta-sedimentary basement rocks is inferred to explain these geochemical characteristics. These processes coincided also with the effusion of high-MgO andesitedacite lavas that display petrological evidence for mixing between andesite-dacite and more mafic magmas. An influx of hotter mafic magma into the system explains why the extent of crustal assimilation recorded by Ruapehu lavas peaked during the ∼50–35 ka eruptive period. From 26 ka to the present, andesite lavas have reverted to more mafic compositions with less potassic melt inclusion and whole-rock compositions when compared to the ∼50–35 ka lavas. We suggest that the younger lavas assimilated less-enriched melts because fertile phases had been preferentially extracted from the crustal column during earlier magmatism. This scenario of bottom-up heating of the lithosphere and exhaustion of fertile phases due to the progressive intrusion of magma explains the geochemical evolution of Ruapehu lavas. This model may be applicable to other long-lived composite volcanoes of the circum-Pacific continental arcs.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Combined Fe-Mg chemical and isotopic zoning in olivine constraining magma
           mixing-to-eruption timescales for the continental arc volcano Irazú
           (Costa Rica) and Cr diffusion in olivine
    • Authors: Oeser M; Ruprecht P, Weyer S.
      Abstract: Arc magmas commonly are mixtures of newly arriving primitive melts, stored magmas at shallow levels, and xenolithic material added on ascent. Almost every eruption has a unique assembly of these components, which may record magmatic processes occurring in the plumbing system prior to an eruption. In this study, we focus on complexly zoned olivines (crustal xenocrysts) to obtain a better understanding of the magmatic processes and the assembly of the 1963–65 erupted magmas of Irazú volcano, one of the most voluminous active volcanoes in Costa Rica. We performed high-precision in situ Fe-Mg isotope analyses by femtosecond-LA-MC-ICP-MS on these olivines, to unravel the origin of their complex chemical zoning (growth, diffusion, or a combination of both processes). This information was used to establish a refined diffusion model to explore magma mixing-to-eruption timescales. Furthermore, trace element analyses using LA-ICP-MS were performed. Chromium displays a chemical zoning in the investigated olivine, which coincides spatially as well as in terms of length scale and geometry with Fe-Mg zoning and that was used to constrain Cr diffusivity in natural olivine.Our findings show that Fe-Mg zoning in Irazú olivine mainly results from Fe-Mg inter-diffusion after two crystal growth episodes as indicated by strongly coupled chemical and isotopic zoning. Simulations of this diffusive process indicate that mixing of these crystals into ascending primitive melts occurred <600 days before their eruption, consistent with a previously reported diffusion study based on Ni zonation in Mg-rich olivines. Trace element characteristics of olivine suggest that the complex-zoned olivine crystals originate from a crystal mush/cumulate in the middle or lower crust and deeper than the shallow magma chamber and were mobilized by mantle-derived magma bearing Mg-rich olivines. Finally, modeling of the observed Cr zoning in the Irazú olivines indicates that the diffusion coefficient for Cr in olivine (DCr) is smaller than DFe-Mg by a factor of 4.9 ± 2.9 at the conditions experienced by these crystals consistent with Cr diffusion experiments at high silica activity in the melt.Our results show that by combining elemental and isotope zoning studies in individual minerals we can refine the timing/assembly of magmatic eruptions and provide independent constraints on element diffusivities. Last, it confirms that primitive arc magmas at Irazú are not aphyric during ascent, but carry primitive phenocrysts from lower crust or Moho depth to the surface.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Feldspar Raman shift and application as a magmatic thermobarometer
    • Authors: Befus KS; Lin J, Cisneros M, et al.
      Abstract: We calibrate the pressure-dependent Raman shift of feldspars by measuring spectra of 9 compositionally diverse plagioclase and alkali feldspars at pressures ranging between 0.1 MPa and 3.6 GPa using a diamond-anvil cell coupled with Raman spectroscopy. We observe up to 12 vibrational modes that are caused by deformation of Si(Al)O4 tetrahedral chains. The most intense modes are ν22, ν24, and ν25, which are produced by stretching and bending of four-membered Si(Al)-O-Si(Al) rings. Because modes are a product of lattice environments, feldspar composition may relate to mode frequency. We find that the frequencies of the ν25 mode correlates with composition, whereas the other intense bands do not correlate with composition. All feldspar compositions exhibit modes that shift linearly (r2 > 0.9) to higher frequencies with increasing pressure. Modes ν22, ν24, and ν25 shift to higher frequencies with slopes that range from 1.7 ± 0.5 to 5.5 ± 1.6 cm–1 GPa–1, and provide the best combination of intensity and pressure-sensitivity. For all compositions the ν22 mode exhibits the most advantageous pressure-dependent (P-T) frequency shift. We use an elastic model, thermodynamic properties, and shear moduli to establish the pressure-temperature dependent sensitivity of feldspar inclusions hosted by garnet, clinopyroxene, and olivine. Raman shifts for all feldspars are <2 cm–1 for crustal and upper lithosphere conditions. Albitic plagioclase inclusions show the least temperature-sensitive inclusion pressures and provide the best barometers, followed by alkali feldspars and anorthitic plagioclase. Our new calibration allows Raman spectroscopy of feldspars to be used to quantify P-T conditions for crustal magmatic rocks, low- to high-grade metamorphic rocks, and the mantle.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Partial melting of ultramafic granulites from Dronning Maud Land,
           Antarctica: Constraints from melt inclusions and thermodynamic modeling
    • Authors: Ferrero S; Godard G, Palmeri R, et al.
      Abstract: In the Pan-African belt of the Dronning Maud Land, Antarctica, crystallized melt inclusions (nanogranitoids) occur in garnet from ultramafic granulites. The granulites contain the peak assemblage pargasite+garnet+clinopyroxene with rare relict orthopyroxene and biotite, and retrograde symplectites at contacts between garnet and amphibole. Garnet contains two generations of melt inclusions. Type 1 inclusions, interpreted as primary, are isolated, <10 μm in size, and generally have negative crystal shapes. They contain kokchetavite, kumdykolite, and phlogopite, with quartz and zoisite as minor phases, and undevitrified glass was identified in one inclusion. Type 2 inclusions are <30 μm in size, secondary, and contain amphibole, feldspars, and zoisite. Type 2 inclusions appear to be the crystallization products of a melt that coexisted with an immiscible CO2-rich fluid.The nanogranitoids were re-homogenized after heating in a piston-cylinder in a series of four experiments to investigate their composition. The conditions ranged between 900 and 950 °C at 1.5–2.4 GPa. Type 1 inclusions are trachytic and ultrapotassic, whereas type 2 melts are dacitic to rhyolitic. Thermodynamic modeling of the ultramafic composition in the MnNCKFMASHTO system shows that anatexis occurred at the end of the prograde P-T path, between the solidus (at ca. 860 °C–1.4 GPa) and the peak conditions (at ca. 960 °C–1.7 GPa). The model melt composition is felsic and similar to that of type 1 inclusions, particularly when the melting degree is low (<1 mol%), close to the solidus. However the modeling fails to reproduce the highly potassic signature of the melt and its low H2O content. The combination of petrology, melt inclusion study, and thermodynamic modeling supports the interpretation that melt was produced by anatexis of the ultramafic boudins near peak P-T conditions, and that type 1 inclusions contain the anatectic melt that was present during garnet growth. The felsic, ultrapotassic composition of the primary anatectic melts is compatible with low melting degrees in the presence of biotite and amphibole as reactants.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Cesium adsorption isotherm on swelling high-charged micas from aqueous
           solutions: Effect of temperature
    • Authors: Osuna FJ; Cota A, Pavón E, et al.
      Abstract: The potential use of a new family of synthetic swelling micas for cesium immobilization from aqueous solution was evaluated and the structural modifications after adsorption were analyzed. The results have revealed that they are good cesium adsorbents compared to natural clays and as the layer charge increases, the adsorption capacity and affinity increase. The cesium ions are adsorbed through a cation exchange mechanism, but an inner sphere complex with the basal O atoms of the tetrahedral sheet is favored. These findings imply that is possible to design minerals with improved environmental applications.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Ni-serpentine nanoflakes in the garnierite ore from Campello Monti (Strona
           Valley, Italy): Népouite with some pecoraite outlines and the processing
           of Ni-containing ore bodies
    • Authors: Capitani G; Ventruti G.
      Abstract: The garnierite ore at Campello Monti occurs as dark green colloform concretions covering surfaces, fractures, and filling veins in harzburgite rocks. The representative composition (Ni2.45Mg0.14Cu0.12Co0.05)∑2.76Si2.10O5(OH)4 is consistent with a 7 Å phase, namely pecoraite or népouite. Relevant chemical features are an exceptionally high Ni/Mg ratio, a significant level of Cu substituting for Ni, and a low content of S, possibly in tetrahedral sites.Olivine and orthopyroxene in the harzburgite host rock are only partially serpentinized, do not contain detectable Ni, and are almost iron free. The green coating probably originated from ground-water solutions that leached nearby weathered peridotites and sulfide ores, and deposited less-mobile elements along fractures and voids of the host peridotite, just outside their provenance area.Bulk techniques such as X-ray powder diffraction and infrared spectroscopy do not confidently distinguish between népouite and pecoraite, although the comparison with synthetic, implicitly pure polymorphs indicates népouite as the best matching phase. On the other hand, HRTEM clearly shows that garnierite is mostly constituted by plumose aggregates made of curved crystals with frayed tips, a few nanometers thick along the stacks and a few tens of nanometers long (nanoflakes). All known lizardite stacking sequences, namely 1T, 2H1, and 2H2, have been locally observed, even though most crystals show stacking disorder.The recorded nanostructure suggests possible explanations for the recurrent anomalies (low oxide totals, high IVT/VIM cation ratios, etc.) found in EMP analyses of garnierites. The small grain size, the high density of defects, and the structural arrangement actually intermediate between lizardite and chrysotile probably explain the ambiguities that occurred during the characterization with bulk techniques. The results obtained in this study may have important implications for ore processing methods.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Presentation of the 2017 Roebling Medal of the Mineralogical Society of
           America to Edward Stolper
    • Authors: McSween HY; Jr..
      Abstract: The Roebling Medal recognizes outstanding research in mineral sciences, and this year's medalist—Edward Stolper—conducts experiments that are arguably the most original and innovative of this generation. His interpretations and insights often upend current thinking and, in the process, turn misconceptions and nonsense into solid gold.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Acceptance of the 2017 Roebling Medal of the Mineralogical Society of
    • Authors: Stolper E.
      Abstract: Thank you, Hap, for that very kind introduction; my friendship and professional relationship with you go back very far, and some of my most enjoyable work has been done with you, so I particularly appreciate your introducing me today. I also want to thank the MSA, those of you who have come to this luncheon, and those who participated in this morning's symposium on “Petrology Across the Solar System”—which was fun and filled with great talks and required people to come a long way. It is all very humbling, particularly when I look at the list of previous recipients extending back to 1929, including people whom I never knew, but whose influence on our field is legendary—Bowen, Schairer, Tilley, Buddington, Khorshkinskii, and so many more; people from generations ahead of me but whom I know (or in some cases, knew) well and whose influence on me personally and professionally has been profound, and about whom I think often for what they taught me that continues to resonate for me—Jim Thompson, Ian Carmichael, Peter Wyllie, and both Don Lindsley and Gary Ernst who are here today; and more recently, people from my cohort who are my friends and whose work shapes and defines in our own time the fields represented by the MSA. I am honored to have my name added to the list.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Presentation of the Mineralogical Society of America Award for 2017 to
           Dustin Trail
    • Authors: Watson E.
      Abstract: Dustin Trail began his scientific career as a computer science major in the early 2000s at the University of Colorado, Boulder. Fortunately for our community of mineralogical scientists, Dustin enrolled (as a third-year student) in Steve Mojzsis' course in Earth History for the purpose of fulfilling a science elective. Anyone who knows Steve or who has heard him speak understands why this might have been a life-changing experience for an impressionable young scientist-in-the-making: Steve is a passionate, mesmerizing speaker who can draw his audience into a story like few others in our field. As it turned out, Steve lured Dustin Trail irretrievably into a new future profession.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Acceptance of the Mineralogical Society of America Award for 2017
    • Authors: Trail D.
      Abstract: Thank you, I am deeply honored to be here today, appreciative to those who consider my science strong enough to write on my behalf, and to the MSA for presenting me with this award. In receiving an early career award, I am left to reflect on how I came to this point. I developed a deep interest in mineralogy and geochemistry near the end of my undergraduate degree in Computer Science. This would never have happened if I had not enrolled in “Historical Geology” taught by Steve Mojzsis. Steve calls it “Hysterical Geology,” which I think is only partially a joke. Whatever the case, he teaches the class exceptionally well, and he captured my interest early. I found myself moving from the back of a rather large class to the front as the semester progressed. What was supposed to be a course to satisfy a degree requirement turned into much more than this. Not long afterward, I inquired about graduate studies in Steve's group. Steve was willing to take a risk on me as a geology M.S. student, with very limited formal training in the natural sciences. For this I will always be grateful.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Presentation of the Dana Medal of the Mineralogical Society of America for
           2017 to Thomas W. Sisson
    • Authors: Bacon CR.
      Abstract: I have the pleasure of introducing Thomas W. Sisson, the Mineralogical Society of America Dana Medalist for 2017. Tom is known for his scientific rigor and landmark publications that have contributed to a diverse spectrum of fields closely tied to the mineralogical sciences. He is particularly recognized for his work on magma differentiation and the role of water in subduction-related magmatism. Beginning with his Ph.D. research with Tim Grove, Tom's early papers showcase difficult high-temperature experiments on hydrous basalt and magmatic processes recorded by the Sierra Nevada batholith. This landmark work was soon followed by ion microprobe measurements of dissolved water concentrations in melt inclusions from a range of arc basalts and by infrared spectrometric determinations of dissolved H2O and CO2 concentrations in unusually primitive arc basalt.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Acceptance of the Dana Medal of the Mineralogical Society of America for
    • Authors: Sisson TW.
      Abstract: Thank you, Charlie, for those kind words. That's a lot to live up to. Thank you also to the selection committee, to those who wrote letters supporting my nomination, and to the Society. In so far as I've been successful, it's due to the opportunities I've been allowed to pursue, the generous mentors and colleagues I've worked with, as well as to strong institutional support.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Presentation of the Distinguished Public Service Award of the
           Mineralogical Society of America for 2017 to David W. Mogk
    • Authors: Gunter ME.
      Abstract: President Harlow, members, and guests. It's my great honor to stand before you today as the citationist for the 2017 MSA Distinguished Public Service Medal to be awarded to Dave Mogk of Montana State University. What I share today are a few personal anecdotes and comments from those who wrote letters of support for Dave—two of whom are a bit on the senior side (i.e., gray hairs) and two who are currently mid-career, but whose comments are directed to how Dave influenced the start of their careers. For the former gray hairs, there are tens of us who could have written similar letters, and for the latter early/mid-career ones, hundreds, but it will really be the thousands born in this century who will benefit from Dave's efforts over the past 30-ish years.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Acceptance of the Distinguished Public Service Award of the Mineralogical
           Society of America for 2017
    • Authors: Mogk DW.
      Abstract: Mr. President, Colleagues, Friends, and Family:
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • New Mineral Names
    • Authors: Gagné OC; Belakovskiy DI, Cámara F.
      Abstract: In this issueThis New Mineral Names has entries for 13 new minerals, including alumovesuvianite, canosioite, currierite, cyprine, dagenaisite, dravertite, ferrorhodonite, fogoite-(Y), manganiceladonite, puninite, wampenite, zincoberaunite, zincostrunzite, and new data on alumoklyuchevskite and kamchatkite.
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
  • Book Review
    • Authors: Cooper CL.
      Abstract: Book Review: Global Volcanic Hazards and Risk. (2015) Edited by LoughlinSusan C., SparksSteve, BrownSarah K., JenkinsSusanna F., Vye-BrownCharlotte et al. Cambridge University Press. ISBN 9781107111752, 403 pages. $124 Hardback (open access online).
      PubDate: Sun, 01 Apr 2018 00:00:00 GMT
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