Partitioning of noble gases, siderophile and radioactive elements between silicates and iron alloys at core-mantle differentiation conditions.

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The accretion of the Earth was a violent series of events dominated by the addition of objects to the growing planet. During the later stages of accretion, these collisions deposited enough energy to at least partly melt the Earth. The result was an ocean of magma. Metal sank through this magma ocean and ponded at its base at roughly the depth of the base of the current upper mantle before transiting through the lower mantle to the center of planet. However, many of the questions about the core-mantle differentiation are still open and much debated. We will generate in the laboratory the actual conditions of the segregation of Earth's metal core from a deep magma ocean for the first time to the highest possible pressures approaching the core-mantle boundary of the Earth in the laser-heated diamond anvil cell. These new methods exceed the P, T limits of most experiments. The project involves close collaboration with national and international researchers, and will provide new insight into the formation of the Earth and composition of the core. The experiments will be conducted on a range of siderophile (metal-loving) and radioactive elements and proto-typical silicate compositions. Most importantly, we will address the behaviour and solubility of noble gases like helium, argon and xenon in metal and silicates at these extreme conditions. Because the rare gases are a fundamental diagnostic of the present state of the Earth's deep interior, our work will contribute to a direct understanding of core-mantle exchange processes throughout Earth evolution.