Stability and structures of hydrous minerals in the transition zone of the Martian mantle

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This research project is aimed at studying the stability and structures of hydrous minerals in the transition zone of the Martian mantle. Hydrous mantle phases will be synthesized in the MgO-FeO(Fe2O3)-SiO2-H2O system at pressures > 10 GPa, using the multi-anvil apparatus. The stability of hydrous phases with iron-rich compositions relevant to the Martian mantle has so far not been explored and potentially new phases could be discovered in this system. Phase identification and characterization will be performed using X-ray diffraction and, in particular, analytical transmission electron microscopy. The TEM examination will involve the determination of the valence state of iron by electron energy-loss spectroscopy (EELS), providing insights into the crystal chemistry of phases and incorporation mechanism of water. To determine the water storage capacity of hydrous phases, the water concentrations will be quantified by IR spectroscopy and directly coupled evolved gas analysis (DEGAS). These data are of fundamental importance for understanding the present and past water cycle and water inventory of Mars. The study may provide explanations for the formation of an ancient ocean, and huge canyons and outflow channels on the surface of Mars that are possibly due to early release of water from a once wet Martian interior.