Experiments were performed on iron-silicon alloys to determine their suitability as analog compositions for the Earth’s core. Starting compositions with 9 wt.% silicon and 16 wt.% silicon were compressed in diamond anvil cells and laser-heated. The melting temperatures of the alloys were measured up to 52 GPa using a recently developed optical system. Both curves show a melting point depression from pure iron but intersect at ∼50 GPa.
The two starting compositions were also studied up to 90 GPa and over 3500 K in synchrotron x-ray diffraction experiments, and phase diagrams were constructed for both compositions that show significant deviation from the pure iron phase diagram. Based on this synchrotron data, a model was produced which predicts the core to contain 8.6 to 11.1 wt.% silicon for a core-mantle boundary temperature of 4000 K.
|Commitee:||Hier-Majumder, Saswata, McDonough, William|
|School:||University of Maryland, College Park|
|School Location:||United States -- Maryland|
|Source:||MAI 48/01M, Masters Abstracts International|
|Keywords:||Core, Earth, Iron-silicon alloys, Pressure|
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