117 results found
Miller LA, Berry AJ, StC O'Neill H, et al., 2023, The effect of composition, temperature and pressure on the oxidation state and coordination environment of copper in silicate melts, Geochimica et Cosmochimica Acta, ISSN: 0016-7037
Crisp LJ, Berry AJ, Burnham AD, et al., 2023, The Ti-in-zircon thermometer revised: The effect of pressure on the Ti site in zircon, Geochimica et Cosmochimica Acta, ISSN: 0016-7037
Bullen JC, Lapinee C, Miller LA, et al., 2022, Spectroscopic (XAS, FTIR) investigations into arsenic adsorption onto TiO<inf>2</inf>/Fe<inf>2</inf>O<inf>3</inf> composites: Evaluation of the surface complexes, speciation and precipitation predicted by modelling, Results in Surfaces and Interfaces, Vol: 9
Over 50 million people in South Asia are exposed to groundwater contaminated with carcinogenic arsenic(III). Photocatalyst-adsorbent composite materials are popularly developed for removing arsenic in a single-step water treatment. Here, As(III) is oxidised to As(V), which is subsequently removed via adsorption. We previously developed a component additive surface complexation model (CA-SCM) to predict the speciation of arsenic adsorbed onto TiO2/Fe2O3 under different environmental conditions, using surface complexes taken from studies of single-phase minerals. In this work, we critically evaluate this approach, using experimental observations of the surface structures of arsenic adsorbed onto TiO2/Fe2O3. Extended X-ray absorption fine structure spectroscopy (EXAFS) indicates significant As(III) surface precipitation, and the possible formation of tridentate 3C complexes. EXAFS was unable to identify As binding modes for TiO2 and Fe2O3 surface complexes simultaneously, highlighting the challenge of analysing composite surfaces. FTIR and zeta potential analysis indicate that As(III)-Fe2O3 surface complexes are protonated at neutral pH, whilst As(III)-TiO2, As(V)-Fe2O3 and As(V)-TiO2 surface complexes are negatively charged. Our study confirms the speciation predicted by CA-SCM, particularly As(III) surface precipitation, but also introduces the possibility of tridentate As(III) at acidic pH. This study highlights how experiment and modelling can be combined to assess surface complexation on composite surfaces.
Crisp LJ, Berry AJ, 2022, A new model for zircon saturation in silicate melts, CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, Vol: 177, ISSN: 0010-7999
Miller LA, O'Neill HSC, Berry AJ, et al., 2022, Fractional crystallisation of eclogite during the birth of a Hawaiian Volcano, NATURE COMMUNICATIONS, Vol: 13
Knafelc J, Bryan SE, Jones MWM, et al., 2022, Havre 2012 pink pumice is evidence of a short-lived, deep-sea, magnetite nanolite-driven explosive eruption, COMMUNICATIONS EARTH & ENVIRONMENT, Vol: 3
Bloch EM, Jollands MC, Tollan P, et al., 2022, Diffusion anisotropy of Ti in zircon and implications for Ti-in-zircon thermometry, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 578, ISSN: 0012-821X
Berry AJ, Miller LA, O'Neill HSC, et al., 2021, The coordination of Cr2+ in silicate glasses and implications for mineral-melt fractionation of Cr isotopes, CHEMICAL GEOLOGY, Vol: 586, ISSN: 0009-2541
O'Neill HSC, Berry AJ, 2021, The oxidation state of chromium in basaltic silicate melts, GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 306, Pages: 304-320, ISSN: 0016-7037
Mare ER, O'Neill HSC, Berry AJ, et al., 2021, Coordination change of Ge4+ and Ga3+ in silicate melt with pressure, GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 303, Pages: 184-204, ISSN: 0016-7037
Berry AJ, O'Neill HSC, Foran GJ, 2021, The effects of temperature and pressure on the oxidation state of chromium in silicate melts, CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, Vol: 176, ISSN: 0010-7999
Jollands MC, O'Neill HS, Berry AJ, et al., 2021, A combined Fourier transform infrared and Cr K-edge X-ray absorption near-edge structure spectroscopy study of the substitution and diffusion of H in Cr-doped forsterite, EUROPEAN JOURNAL OF MINERALOGY, Vol: 33, Pages: 113-138, ISSN: 0935-1221
Weng Z, Retita I, Tseng Y-S, et al., 2021, gamma-MgH2 induced by high pressure for low temperature dehydrogenation, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Vol: 46, Pages: 5441-5448, ISSN: 0360-3199
Berry AJ, Oneill HSC, 2021, Oxygen Content, Oxygen Fugacity, the Oxidation State of Iron, and Mid-Ocean Ridge Basalts, Vol: 266, Pages: 155-163, ISSN: 0065-8448
Oxygen is the third most abundant element in the Solar System and the most abundant in the silicate Earth. As the second most electronegative element its concentration in silicate rocks is fixed by the concentrations and oxidation states of the cations to which it bonds as O2−. All of the major cation forming elements in terrestrial silicates have only one oxidation state, except for Fe. Thus, charge balancing with Fe is the only significant reason for variability in the amount of O in silicate rocks. It is difficult to measure differences in the oxygen content of rocks directly and instead it is usually proxied by Fe3+/Fe2+. The Fe3+/Fe2+ of a rock is often used to define an oxygen fugacity (fO2), however, the relationship between Fe3+/Fe2+ and fO2 is not monotonic, as illustrated by the quartz-fayalite-magnetite (QFM) oxygen buffer where at constant fO2 Fe3+/Fe2+ can vary from ~ 0 to 2. Since 1991 the empirical expression of Kress and Carmichael has been used to relate the oxidation state of Fe to fO2, temperature, compo-sition, and pressure. A feature of this expression is the non-ideal dependence of Fe3+/Fe2+ on fO2, suggesting Fe-Fe interactions. However, recent studies have shown that Fe3+/Fe2+ behaves ideally. This has necessitated a refit of the available data. The new expression, for compositions with < 60 wt% SiO2, is log10(Fe3+/Fe2+) = 0.25 ΔQFM – 1.35 + 0.023[CaO] + 0.034[Na2O] + 0.044[K2O] – 0.018[P2O5], where fO2 is in log units relative to QFM (and thus temperature does not need to be specified) and the oxide components are in weight percent. This equation reproduces the data from the Carmichael laboratory better than their original expression and identifies offsets in the literature data that distorted their fit. The average Fe3+/ΣFe (where ΣFe = Fe2+ + Fe3+) value of mid-ocean ridge basalt (MORB) glasses was found to be 0.10 by XANES spectroscopy, which is consistent with the result of the most recent redox tit
Sievwright RH, O'Neill HSC, Tolley J, et al., 2020, Diffusion and partition coefficients of minor and trace elements in magnetite as a function of oxygen fugacity at 1150 oC, Contributions to Mineralogy and Petrology, Vol: 175, Pages: 1-21, ISSN: 0010-7999
Lattice diffusion coefficients and partition coefficients have been determined for Li, Mg, Al, Sc, Ti, Cr, V, Mn, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, In, Lu, Hf, Ta and U in single crystals of natural magnetite as a function of oxygen fugacity (fO2) at 1150 °C and 1 bar by equilibration with a synthetic silicate melt reservoir. Most experiments were run for twelve hours, which was sufficient to generate diffusion profiles from 25 to > 1000 µm in length. The results were checked at one condition with two additional experiments at 66.9 and 161 h. The profiles were analysed using scanning laser-ablation inductively-coupled-plasma mass-spectrometry. Diffusion coefficients (D) were calculated by fitting data from individual element diffusion profiles to the conventional diffusion equation for one-dimensional diffusion into a semi−infinite slab with constant composition maintained in the melt at the interface. Equilibrium magnetite/melt partition coefficients are given by the ratio of the interface concentrations to those in the melt. Plots of log D as a function of log fO2 produce V-shaped trends for all the investigated elements, representing two different mechanisms of diffusion that depend on (fO2)−2/3 and (fO2)2/3. Diffusion coefficients at a given fO2 generally increase in the order: Cr < Mo ≈ Ta < V < Ti < Al < Hf ≈ Nb < Sc ≈ Zr ≈ Ga < In < Lu ≈ Y < Ni < U ≈ Zn < Mn ≈ Mg < Co < Li < Cu. Thus, Cu contents of magnetites are most susceptible to diffusive reequilibration, whereas the original content of Cr should be best preserved.
Mare ER, O'Neill HSC, Berry AJ, et al., 2020, The stability of divalent Ge in silicate melts and its geochemical properties, CHEMICAL GEOLOGY, Vol: 532, ISSN: 0009-2541
O'Neill HSC, Berry AJ, Mallmann G, 2019, The oxidation state of iron in Mid-Ocean Ridge Basaltic (MORB) glasses: Implications for their petrogenesis and oxygen fugacities (vol 504, pg 152, 2018), EARTH AND PLANETARY SCIENCE LETTERS, Vol: 527, ISSN: 0012-821X
Miller LA, O'Neill HSC, Berry AJ, et al., 2019, The oxidation state and coordination environment of antimony in silicate glasses, CHEMICAL GEOLOGY, Vol: 524, Pages: 283-294, ISSN: 0009-2541
Le Losq C, Berry AJ, Kendrick MA, et al., 2019, Determination of the oxidation state of iron in Mid-Ocean Ridge basalt glasses by Raman spectroscopy, AMERICAN MINERALOGIST, Vol: 104, Pages: 1032-1042, ISSN: 0003-004X
McKay D, Moran RF, Dawson DM, et al., 2019, A Picture of Disorder in Hydrous Wadsleyite-Under the Combined Microscope of Solid-State NMR Spectroscopy and Ab Initio Random Structure Searching, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 141, Pages: 3024-3036, ISSN: 0002-7863
O'Neill HSC, Berry AJ, Mallmann G, 2018, The oxidation state of iron in Mid-Ocean Ridge Basaltic (MORB) glasses: Implications for their petrogenesis and oxygen fugacities, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 504, Pages: 152-162, ISSN: 0012-821X
Faul UH, Cline CJ, Berry A, et al., 2018, Constraints on oxygen fugacity within metal capsules, PHYSICS AND CHEMISTRY OF MINERALS, Vol: 45, Pages: 497-509, ISSN: 0342-1791
Cline CJ, Faul UH, David EC, et al., 2018, Redox-influenced seismic properties of uppermantle olivine, NATURE, Vol: 555, Pages: 355-+, ISSN: 0028-0836
Berry AJ, Stewart GA, O'Neill HSC, et al., 2018, A re-assessment of the oxidation state of iron in MORB glasses, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 483, Pages: 114-123, ISSN: 0012-821X
Jollands MC, O'Neill HSC, Van Orman J, et al., 2018, Substitution and diffusion of Cr2+ and Cr3+ in synthetic forsterite and natural olivine at 1200-1500 degrees C and 1 bar, GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 220, Pages: 407-428, ISSN: 0016-7037
Kusiak MA, Wilde SA, Wirth R, et al., 2017, Detecting micro-and nanoscale variations in element mobility in high-grade metamorphic rocks: Implication for precise U-Pb dating of zircon, Microstructural Geochronology: Planetary Records Down to Atom Scale, Pages: 279-291, ISBN: 9781119227243
Reliable geochronology is fundamental to our understanding of planetary evolution and the geological events that have shaped the Earth. Zircon has a robust crystal structure and is a key mineral in geochronological studies because it incorporates small amounts of actinides during growth. Currently, the best physical evidence for the presence of differentiated crust in the first 500 million years of the Earth's history comes from intra-grain isotopic microanalysis of zircon crystals. However, it has been long recognized that isotope systematics in zircon can show great complexity, not only from the presence of multiple stages of growth in single grains, but also from disturbance of accumulated radiogenic Pb during subsequent geological events. Although geochronologists are aware of the problem of Pb mobilization during metamorphism, the nature of mobilization on a submicron scale is not entirely understood, especially where evidence has emerged of inhomogeneity and unsupported radiogenic Pb migration. The recent discovery of nanospheres of metallic radiogenic Pb in zircon from granulites explains, in part, instances of reversely discordant age measurements and irregular counts on Pb isotopes during analysis by secondary ion mass spectrometry (SIMS). Studies are continuing to reveal the nature of Pb nanospheres, so that possible mechanisms and conditions requisite for their formation can be proposed for testing by future investigations.
Berry AJ, Schofield PF, Kravtsova AN, et al., 2017, The limitations of hibonite as a single-mineral oxybarometer for early solar system processes, CHEMICAL GEOLOGY, Vol: 466, Pages: 32-40, ISSN: 0009-2541
Sievwright RH, Wilkinson JJ, O'Neill HSC, et al., 2017, Thermodynamic controls on element partitioning between titanomagnetite and andesitic–dacitic silicate melts, Contributions To Mineralogy and Petrology, Vol: 172, ISSN: 1432-0967
Titanomagnetite–melt partitioning of Mg, Mn, Al, Ti, Sc, V, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Hf and Ta was investigated experimentally as a function of oxygen fugacity (fO2) and temperature (T) in an andesitic–dacitic bulk-chemical compositional range. In these bulk systems, at constant T, there are strong increases in the titanomagnetite–melt partitioning of the divalent cations (Mg2+, Mn2+, Co2+, Ni2+, Zn2+) and Cu2+/Cu+ with increasing fO2 between 0.2 and 3.7 log units above the fayalite–magnetite–quartz buffer. This is attributed to a coupling between magnetite crystallisation and melt composition. Although melt structure has been invoked to explain the patterns of mineral–melt partitioning of divalent cations, a more rigorous justification of magnetite–melt partitioning can be derived from thermodynamic principles, which accounts for much of the supposed influence ascribed to melt structure. The presence of magnetite-rich spinel in equilibrium with melt over a range of fO2 implies a reciprocal relationship between a(Fe2+O) and a(Fe3+O1.5) in the melt. We show that this relationship accounts for the observed dependence of titanomagnetite–melt partitioning of divalent cations with fO2 in magnetite-rich spinel. As a result of this, titanomagnetite–melt partitioning of divalent cations is indirectly sensitive to changes in fO2 in silicic, but less so in mafic bulk systems.
Burnham AD, Berry AJ, 2017, Formation of Hadean granites by melting of igneous crust, NATURE GEOSCIENCE, Vol: 10, Pages: 457-+, ISSN: 1752-0894
Yaxley GM, Berry AJ, Rosenthal A, et al., 2017, Redox preconditioning deep cratonic lithosphere for kimberlite genesis - evidence from the central Slave Craton, SCIENTIFIC REPORTS, Vol: 7, ISSN: 2045-2322
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