One of the most basic enterprises in the Earth Sciences is to understand the relation between the structure of a material and its properties. Many of the important questions currently being addressed in seismology, geodynamics, structural geology and petrology, for example, requires the input of hard, physical measurements of material properties.

A major new collaborative research project (Tosdal, Oldenburg, Russell, Dipple, Scoates) between the Geophysical Inversion Facility and the Mineral Deposits Research Unit in EOS requires measurement of magnetic susceptibility and density of rock samples from four major ore deposits. The physical property data form the bridge between the geologic data (field maps and drill programs) and the remote sensing of unexplored mineral deposits. These data are essential for inverting geophysical measurements into predictions of the geometry and distribution of ore deposits. To evaluate the potential of volcanic deposits to act as natural storage depots for hazardous material, their physical properties and how the properties change with changing physical conditions (such as P,T) must be known. Russell and Kennedy are currently addressing this problem. The structural geometry of mantle lithosphere, which provides insight into mantle convection processes can only be deduced using seismology. To generate an accurate geophysical model of mantle geometry, the elastic properties of lithospheric lithologies (e.g. Vp/Vs) must be known. M.G. Bostock and M.G. Kopylova both use elastic property data in their research on the behaviour of the lithospheric mantle.

The rheological behaviour of the geomaterials (i.e. the relationship between stress, strain and strain rate), ranging from the melt material (volcanic and intrusive) through to the lower mantle, controls the manner in which the Earth deforms. Quantification of the rheological behaviour of materials can only be accomplished through experimental deformation, which provides the data required to formulate an empirical constitutive flow law for the material of interest. Using these flow laws, we can predict the strength or the strain rate of various rock types, hence of various locations within the earth, under a range of physical conditions (e.g. P,T, Fluid composition). This information allows us to predict fundamentally important issues regarding Earth's behaviour, such as the strength of mantle convection, the timescales of compaction and welding in volcanic tuffs (J.K. Russell), and the potential strength of earthquakes (E. Hearn, L.A. Kennedy).

The rock deformation equipment housed in CESL is diverse and innovative. For example, we can measure crack development and fluid flow in large samples (see table below) under brittle conditions or the generation of melts from materials under high temperatures. Rock deformation experiments are performed so that we can determine the mechanism and evolution of deformed rocks and to quantify their rheological behaviour.

Measurements made: Rock strength (i.e. rheology) at a variety of physical conditions (i.e. temperature, confining pressure, pore fluid pressure, fluid chemistry). Obtain differential stress, strain and strain rate relationships as a function of extrinsic parameters.

Grigg's Rig - Solid Medium Device Large Scale Rig

This equipment historically was an internationally renowned centre for phase equilibrium studies. The modern manifestation of this research lies in the exploration of the role of trace elements and isotopes in tracking chemical processes as well as in the mechanisms and rates of sorption and reaction. The equipment is also essential for the synthesis of starting materials for other experimental investigations.

Detailed characterization of the physical properties of starting materials and run products is essential for the extraction of rate laws and constitutive relationships. The same equipment can be used to make measurements on natural samples, thus provided a firm bridge from the experimental realm to the field.