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Research Activities 2007

Earth Materials and Processes   Click on the links below to read the 2007 Earth Materials and Processes research highlights or Click HERE to download the PDF version 46 pages 2.9Mb

Introduction

The former Earth Materials area has been renamed Earth Materials and Processes to reflect better the diversity of the science we do. The area comprises groups in Experimental Petrology, Rock Physics, Thermochronology, and Structure & Tectonics. The research of these groups centres around laboratory based measurements under controlled conditions, simulating those occurring in nature, but these activities are complimented by field based observations, often in collaboration with scientists from other institutions, nationally and internationally. Through such investigations we are developing understanding of the structure and chemical composition of planetary interiors, and the processes by which they evolve. Our interests start at the very beginning of solar system history with how the Earth and other rocky planets accrete, and encompasses core formation, mantle convection, volcanism, metamorphism, global tectonics and the formation of ore deposits.

Areas of current research activity include:

• The making of terrestrial planets. Chemical constraints on the accretion of the Earth and similar planets from the solar nebula, and the processes of core formation; mineralogical and chemical properties of the deep mantle and their influence on global tectonics.
  
  
• The nature of the Earth's upper mantle. Experimental studies and thermodynamic modelling of the phase equilibria relevant to upper mantle melting and ultra-high-pressure metamorphism associated with crustal thickening and subduction; experimental and microstructural studies of phenomena associated with lattice defects and grain boundaries including incorporation of water into nominally anhydrous minerals and microscopic mechanisms of seismic wave attenuation; experimental studies and modelling of grain-scale melt distribution and its implications for melt transport, rheology and seismic properties.
  
  
• Coupling between fluid flow and fault mechanics in the continental crust Experimental studies of the role of fault healing and sealing processes in controlling the time dependence of fault strength and permeability at high temperatures and pressures; complementary field-based and modelling studies exploring fluid-driven growth of shear networks with applications to understanding the development of lode gold systems, especially in the Western Australian goldfields.
  
  
• Oxidation state and coordination of metal ions at high temperatures. Studies of crystals, melts and hydrothermal solutions by X-ray absorption spectroscopy, using synchrotron radiation. Studies of silicate glasses and melts to very high temperatures under controlled redox conditions. Analysis of hydrothermal solutions trapped in synthetic fluid inclusions is providing important basic information on metal complexes at high temperatures.

Research Projects

Experimental Petrology

Introduction

A preliminary investigation of chlorine XANES in silicate melts - Katy Evans

The effect of CO₂ on the speciation of RbBr in solution at temperatures to 650 degrees C and pressures to 0.65 GPa - Katy Evans

Clarification of the Influence of Water on Mantle Wedge Melting - David Green

Accessory phase control on the trace element signature of subduction zone fluids - Jörg Hermann

The limitations of using unpolarized absorbance spectroscopy on anisotropic minerals - István Kovács

Vanadium partitioning and mantle oxidation state - Guil Mallmann

Collisional erosion and the non-chondritic composition of the terrestrial planets - Hugh O'Neill

The dependence of upper mantle melting temperatures on composition: A parameterization for peridotite based on the Gibbs phase rule - Hugh O'Neill

Interactions between felsic melts and peridotites in sub-arc conditions: Comparison between experimental results and natural samples - Cassian Pirard

Subduction recycling of continental sediments and the origin of geochemically enriched reservoirs in the deep mantle - Robert Rapp

Chlorine Partitioning: The Behavior of Cl in the Presence of Sulfide - Silicate Melts and Aqueous Fluid - Heather Sparks

Ti site occupancy and distribution in zircon: implications for thermometry - Nicholas Tailby

Rock Physics

Exploration potential of stress transfer modelling in fault-related mineral deposits - Steven Micklethwaite

High-temperature viscoelasticity and seismic wave attenuation: materials, methods and micromechanical modelling - Ian Jackson

Fault weakening and slow earthquakes as a consequence of fault gouge strengthening in hydrothermal regimes - insights from laboratory experiments - Silvio Giger

Structure & Tectonics

Cycles of lithospheric thickening and thinning along convergent plate margins: A case study from the European Alps - Marco Beltrando

Evidence for competing movement patterns influencing the evolution of the Sagaing-Sumatra wrench fault system - Abhijit Deonath

Tectonic Sequences Diagrams: Is orogeny simple? - Marnie Forster

Pplates - tectonic reconstruction software - Joe Kurtz

Geodynamics of the Sumatran Earthquakes - Gordon Lister

Geochronology of the Omo Group, Turkana Basin, east Africa - Ian McDougall

Virtual Earth - Simon Richards

Structural reactivation along the Portsoy lineament during extension and coeval High-T, Low-P Barrovian metamorphism - Simon Richards

Barrovian and Buchan metamorphism in Scotland as the result of lithospheric-scale extension during orogenesis - Daniel Viete