EGU General Assembly 2008
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  Information - GMPV01 Chemistry of Earths Mantle and Core: Experimental and Theoretical Approaches (incluing Outstading Young Scientist Award Lecture)

Event Information
The picture of Earth’s deep structure is rapidly improving as larger observational geophysical data sets are complemented by modern computation-intensive tools such as tomography. The larger goal of deep Earth geochemistry and mineral physics is to measure and understand effects of pressure, temperature, and composition (P-T-X) on the elasticity, density (volume), and structure of the Earth-forming minerals. Possible chemical reactions at extreme conditions provide valuable constrains for composition of the Earth’s mantle and core. For example, composition of the Earth’s outer core is a geochemical parameter crucial for understanding the evolution and current dynamics of our planet. Since it was recognized that the liquid metallic outer core is about 10% less dense than pure iron, different elements, lighter than iron, including Si, S, O, C, and H, were proposed as major, or at least significantly abundant elements in the Earth’s core. However, the combination of experimental results with geochemical and cosmochemical considerations show that it is unlikely that any one of these elements alone can account for the density deficit.
The questions of the chemical composition of the Earth’s core and mantle, partitioning of elements at high pressures and temperatures, are closely related to the chemical history of the planet, particularly to the processes of accretion and segregation of the planetary body. In fact, the segregation of iron-rich metal from silicate was a major physical and chemical event in the early development of the Earth and must have involved the separation of liquid metal from either liquid or crystalline silicates. Although element partitioning between liquid metals and complex oxides has been successfully studied at pressures below 25 GPa in multi-anvil apparatus, investigations of chemical reactions at higher pressures require diamond anvil cells experiments.
Studying of chemical reactions in the megabar pressure range, and temperatures exceeding 2000 K is not a trivial task. The amount of reacted material is very small (in the order of a few wt. percent, or, in absolute values, in the order of 10-10 g). Despite high temperatures, spatial temperature distribution across the pressure chamber is not homogeneous. The material can be partially, or completely lost when the cell, containing the recovered sample, is opened. There are a number of important details, which are crucial for the success of such experiments.
We invite contributions aimed at addressing the following issues:
- Novel experimental and theoretical techniques in studies chemical reactions at elevated pressures and temperatures;
- New data on chemical reactions involving most abundant in Earth’s interior phases (including perovskites and post-perovskites, magnesiowüstite, silica phases, iron and iron-nickel alloys etc.);
- Effect of magnetic and electronic (including high-to-low spin) transitions on element partitioning at high pressures and temperatures;
- Experimental and theoretical constrains on chemical compositions of Earth mantle and core.

Preliminary List of Solicited Speakers

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