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In this section an overview of the most important on-going projects is given. Information concerning recently-completed projects can be obtained from the publication lists of sections 4.1 and 4.2. Please note that the following contributions should not be cited.

3.1 Physical Properties of Solids

An understanding of the interior of the Earth cannot be gained from direct observations; instead it must come from a combination of disciplines. Researchers within the Geoinstitut seek to constrain the physical, mechanical and chemical properties of minerals that are likely to occur within the Earth's mantle through experimental studies.

In order to develop an understanding of the structure of the deep Earth and the processes that occur within it, one must have a clear understanding of the structures of individual minerals on the atomic scale. Atomic arrangements generally vary in response to pressure and temperature and may lead to phase transitions or changes in local structure of minerals. Detailed studies of the atomic arrangements of potential mantle minerals are of fundamental importance as the structure within a solid determines its physical, mechanical and chemical properties.

Laboratory measurements of the physical properties (e.g., elastic and electrical properties of mantle minerals collected as a function of pressure, temperature, composition and microstructure) provide the information necessary to derive mineralogical and geochemical models of the Earth's mantle. These types of measurements, which form a significant component of the work performed within the Geoinstitut, are also crucial in providing us with information that will lead to an improved understanding of the rheological behavior of the Earth.

Although rheology is one of the most important physical properties that controls mantle convection, the rheological properties of most mantle minerals are very poorly known. The installation of a Paterson deformation apparatus and a new scanning electron microscope in the Geoinstitut within the last year has strengthened dramatically the ability to measure the rheological properties of Earth materials. The combination of these two pieces of equipment enable well-constrained studies of the rheological behavior of materials and the subsequent study of the crystallographic preferred orientations within samples deformed in well defined geometries. The innovative high pressure experimental methods developed at the Geoinstitut within the last 4-5 years continue to place constraints on the rheology of materials under the pressures and temperatures of the Earth's mantle, most specifically with information about the active dislocation slip systems and changes in deformation mechanisms that may occur with increasing pressure.