Partial Melting of the Inner Core

2019 Fiscal Year Research-status Report

• Project/Area Number: 19K04035
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: ハーンルンド ジョン 東京工業大学, 地球生命研究所, 教授 (30723712)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: Inner Core

Outline of Annual Research Achievements

(1) Recruited PhD student to project. She will extend the results and application to generalized planets/exoplanets.
(2) Collected phase equilibria data from mineral physics literature and colleagues. The data includes estimates of uncertainties, we will propagate uncertainties through all of the models.
(3) Finished basic 1D evolution models of inner core growth and reproduced solutions from previous studies. Binary phase equilibria and self-consistent treatment of melting/freezing is also implemented. Student Bonati has run evolution calculations for general planet/core sizes and a manuscript is in preparation for submission.
(4) We discovered that crystallization models for the F layer above the inner core boundary depend on light alloy in the core! Our manuscript is in preparation.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

The main research plan is progressing as originally proposed. The capabilities to do higher dimensional melting/freezing dynamics have now been added to powerful parallel codes and made available to the entire geophysics community, this will be a great help for the project goals. We are very pleased with the unexpected discovery of a dependence on the style of crystallization above the inner core boundary that depends on the alloy composition of the core, one of the most important unsolved problems in geoscience. We now understand how the phase relations and their dependence on pressure give rise to divergent behaviors.

Strategy for Future Research Activity

The plans are unchanged, the main goal is to understand how freezing and re-melting in the inner core gives rise to "partial melting" and melt segregation, this is a completely new contribution to thinking about the inner core and it has very important impacts on many aspects of core science.

Causes of Carryover

Delay of purchases/travel to subsequent fiscal year.