Imperial College London

DrAndrewBerry

Faculty of EngineeringDepartment of Earth Science & Engineering

Visiting Reader
 
 
 
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Contact

 

+44 (0)20 7594 7402a.berry

 
 
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Location

 

1.46ARoyal School of MinesSouth Kensington Campus

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Summary

 

Overview

  • Natural Environment Research Council New Investigators Scheme
    A.J. Berry
    The geochemistry of redox variable elements
    2006: £78006
  • Natural Environment Research Council Small Grant
    A.J. Berry, S. Weyer, and A.B. Woodland
    An experimental investigation of the partitioning of iron isotopes between silicate melt and spinel as a function of oxygen fugacity
    2006: £31651
  • Leverhulme Trust
    S. Wimperis, S.E. Asbrook, and A.J. Berry
    High resolution 17O NMR studies of high-pressure silicate phases.
    2004-2006: £66189
  • Australian Research Council Discovery Project
    A.J. Berry
    The geochemistry of trace elements with variable oxidation state.
    2004-2006: A$120000
  • Australian Research Council Discovery Project
    A.J. Berry and J. Hermann
    Water storage in the Earth's mantle - understanding the process of OH incorporation in olivine.
    2003-2004: A$87000
  • Australian Research Council Linkage Infrastructure Equipment and Facilities
    P.A. Lay, G.J. Foran, M.C. Ridgway, I.R. Gentle, S.P. Best, M.J. Riley, A.J. Berry, A.R. Gerson, T.W. Hambley, S.K. Bhargava, R.F. Garrett, and D.C. Creagh.
    Fluorescence Detector for the Australian National Beamline Facility.
    2003: A$507000
  • Australian Research Council Post-Doctoral Fellowship
    A.J. Berry
    Speciation of metal ions responsible for ore-metal transport at elevated temperatures.
    1997-2000: A$177009
  • Australian Synchrotron Research Program
    12 grants for work on the oxidation state of redox variable elements in silicate melts.
    1998-2004: A$69360
  • Access to Major Research Facilities Program
    10 grants for work on redox variable elements in melt and fluid inclusions.
    1999-2003: A$77144
  • Australian Institute of Nuclear Science and Engineering
    Refinement of hydrogen positions in natural titanian-clinohumite by powder neutron diffraction.
    2001: A$2400
  • The effect of oxidation state on the geochemical behaviour of metals in magmatic systems
  • The incorporation of water in nominally anhydrous mantle minerals
  • The transport of ore-metals in hydrothermal solutions

These problems are investigated by applying a variety of spectroscopic techniques (in particular X-ray absorption spectroscopy using a synchrotron light source; http://www.diamond.ac.uk/) to both natural and synthetic samples.

PhD Projects

1. Ce and Eu anomalies in zircon: possible indicators of the oxygen fugacity of ancient magmas [Details]


Zircon is an extensively studied mineral due to its importance in U-Pb dating.  When a zircon crystallises from a melt it commonly incorporates not only U but also small amounts of the rare-earth elements.  These elements usually behave similarly because they are of similar size and occur exclusively as trivalent cations, except for Ce and Eu.  Ce occurs as both Ce3+ and Ce4+ and Eu as Eu3+ and Eu2+.  A positive Ce "anomaly" is interpreted to mean an abundance of Ce4+, or oxidising conditions, which allows Ce4+ to readily substitute for Zr4+.  A negative Eu anomaly is usually attributed to the presence of Eu2+ in the melt, or reducing conditions, since Eu2+ partitions less readily into zircon than Eu3+.  Many zircons exhibit both positive Ce and negative Eu anomalies, contradictorily indicating both oxidised and reduced conditions.  The origin of this "signature" is unknown.

One possible solution to the conundrum is that Ce4+ and Eu2+ may sometimes coexist.  It is not currently known how the Ce4+/Ce3+ and Eu3+/Eu2+ ratios vary in magmas as a function of geological conditions.  The aim of this project is to determine the oxidation states of these two elements as a function of oxygen fugacity.  If the magnitude of the anomalies can be correlated with oxygen fugacity then this may provide a new tool for estimating the crystallisation environment of ancient melts.  The project will involve the preparation of synthetic melts and their in situ analysis using X-ray Absorption Spectroscopy at a synchrotron light source.  In particular it is hoped to make use of the new ?235 million UK synchrotron called Diamond, which will become available for researchers early in 2007.  Experiments may additionally be undertaken in the USA (Advacned Photon Source), Japan (Photon Factory), or France (European Synchrotron Radiation Facility).

2. An experimental investigation of the fractionation of iron isotopes between silicate melt and spinel as a function of oxygen fugacity


Iron (Fe) is the most common element in the Earth's mantle that occurs in more than one oxidation state (as Fe2+ and Fe3+).  It also occurs as four isotopes (54Fe, 56Fe, 57Fe and 58Fe).  It has only recently been discovered that these isotopes may be fractionated during high temperature mantle processes such as partial melting.  In particular mantle spinels exhibit a correlation between isotope fractionation and oxygen fugacity, which controls the relative amounts of Fe3+ and Fe2+.  The importance of oxygen fugacity in controlling this fractionation relative to other process such as mantle metasomatism is unclear.  There is currently no experimental evidence to independently establish the effect of variable Fe3+/Fe2+ on the fractionation of Fe isotopes in spinel at magmatic temperatures.  In this project a series of spinels will be crystallised from a melt as a function of oxygen fugacity.  The samples will be prepared by equilibrating a melt, with spinel on the liquidus, at atmospheric pressure in a controlled gas environment.  After quenching, the spinel and melt will be separated and analysed by M?ssbauer spectroscopy to determine Fe3+/Fe2+, and with a high-resolution multi-collector inductively coupled plasma mass spectrometer to determine the Fe isotopic ratios.  This will allow oxygen fugacity, the Fe3+/Fe2+ ratio, and isotope fractionation to be directly correlated.  Experiments of this type are essential if variations in Fe isotopic measurements of natural samples are to be correctly interpreted, thus providing a new tool for tracking mantle processes.  This project applies techniques commonly used in the area of experimental petrology to an emerging area of isotope geochemistry.

3. The geochemistry of copper and the formation of porphyry ore deposits [Details]

MSci Projects:

The weird and wonderful rocks of Disko Island (with Matt Genge)


The rocks of Disko Island, Greenland are probably the most reduced on Earth and thus can be viewed as analogues for some extra-terrestrial material.  The rocks of interest were formed by the interaction of a basaltic magma with a coal seam.  This resulted in very reduced conditions and produced a melt containing metallic iron and otherwise very different mineralogy and geochemistry to normal terrestrial igneous rocks.

The aim of this project is to investigate the geochemistry of these rocks using the scanning electron microscope (SEM), electron microprobe, and possibly laser-ablation ICPMS at the Natural History Museum.  In particular the partitioning of trace elements between crystals and glass will be used to identify the oxidation state of these elements and estimate the oxygen fugacity of the original melt.

Sulfur in magmas and volcanic eruptions


Volcanic eruptions emit sulfur which contributes to global cooling and acid rain.  For example the emissions of sulfur from the 1991 eruption of Mt Pinatubo in the Philippines lowered the average temperature of the Earth by 0.5 C, while the 1815 eruption of Tambora resulted in "the year without a summer".

Sulfur may be dissolved in magmas as sulfide, sulfate or possibly sulfite.  If it occurs as sulfide the sulfur is locked away and wont effect the environment.  While we cant prevent volcanoes releasing sulfur we can try and estimate the proportion that would be present as sulfide and thus the environmental significance of an eruption either in the future or at some point in Earth's history.  The ratio of sulfide to sulfate is also important for understanding the oxygen fugacity of a magma and the potential for associated mineralisation.

The aim of this project is to quantify the amount of sulfide relative to sulfate in volcanic glasses using the electron microprobe at the Natural History Museum.

Oceans of water deep in the Earth?


Think of all the water on the surface of the Earth - in the rivers, lakes, oceans.  As much as 10 times this amount may be present deep in the Earth's mantle.  So where is it?  Is there some huge underground ocean?  No, instead all this water is likely to be dissolved in minerals such as olivine and pyroxene which don't normally contain water.  The amount of water and the way in which it is dissolved drastically effects things like the speed of seismic waves, melting temperatures, and the viscosity or flow of the mantle.

In this project the amount of water contained in samples of mantle olivine from Kamchatka in Russia will be determined.  The samples will be analysed by infrared spectroscopy using facilities at the Natural History Museum.

The "colour" of Cu in ore-forming fluids (with Jamie Wilkinson)


Most of the world's ore deposits form as a result of the transport and concentration of metals by high temperature fluids.  Samples of the fluid that produced a deposit are often trapped as fluid inclusions in quartz.  This allows insig ht into the conditions needed for a deposit to occur.  One of the great unknowns in ore-deposit research is how an ore metal such as Cu occurs in the fluid e.g. is it associated with Cl or S or O.& #160; This is important since the coordinating elements control the sta bility of the dis solved Cu which determines when and how the metal will precipitate from solution as an ore.

Cu complexes often change colour when there is a change in the coordinating elements e.g. malachite is green and azurite is blue.  This project aims to determine the colour of Cu complexes trapped in fluid inclusions.  The samples will be analysed using a micro-optical absorption spectrometer at the Natural History Museum.

  • Natural Environment Research Council New Investigators Scheme
    A.J. Berry
    The geochemistry of redox variable elements
    2006-: ï¿¡78006
  • Natural Environment Research Council Small Grant
    A.J. Berry, S. Weyer, and A.B. Woodland
    An experimental investigation of the partitioning of iron isotopes between silicate melt and spinel as a function of oxygen fugacity
    2006-: ï¿¡31651
  • Leverhulme Trust
    S. Wimperis, S.E. Asbrook, and A.J. Berry
    High resolution 17O NMR studies of high-pressure silicate phases.
    2004-2006:ï¿¡66189
  • Australian Research Council Discovery Project
    A.J. Berry
    The geochemistry of trace elements with variable oxidation state.
    2004-2006: A$120000
  • Australian Research Council Discovery Project
    A.J. Berry and J. Hermann
    Water storage in the Earth's mantle - understanding the process of OH incorporation in olivine.
    2003-2004: A$87000
  • Australian Research Council Linkage Infrastructure Equipment and Facilities
    P.A. Lay, G.J. Foran, M.C. Ridgway, I.R. Gentle, S.P. Best, M.J. Riley, A.J. Berry, A.R. Gerson, T.W. Hambley, S.K. Bhargava, R.F. Garrett, and D.C. Creagh.
    Fluorescence Detector for the Australian National Beamline Facility.
    2003: A$507000
  • Australian Research Council Post-Doctoral Fellowship
    A.J. Berry
    Speciation of metal ions responsible for ore-metal transport at elevated temperatures.
    1997-2000: A$177009
  • Australian Synchrotron Research Program
    12 grants for work on the oxidation state of redox variable elements in silicate melts.
    1998-2004: A$69360
  • Access to Major Research Facilities Program
    10 grants for work on redox variable elements in melt and fluid inclusions.
    1999-2003: A$77144
  • Australian Institute of Nuclear Science and Engineering
    Refinement of hydrogen positions in natural titanian-clinohumite by powder neutron diffraction.
    2001: A$2400

Research Student Supervision

Doyle,T