ANU - Research School of Earth Sciences - ANU College of Physical and Mathematical Sciences

Untitled Document

Research Activities 2008

Earth Materials and Processes

Click on the links below to read the 2008 Earth Materials and Processes research highlights or Click HERE to download the PDF version 35 pages 3.58Mb

Introduction

The Earth Materials and Processes area comprises groups in Experimental Petrology, Rock Physics, Thermochronology, and Structure & Tectonics. Our research centres around laboratory based measurements under controlled conditions, simulating those occurring in nature, but these activities are complimented by a rich array of analytical equipment and are supported by extensive 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, but also covers the ongoing processes of 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.