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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Earth Sci. | doi: 10.3389/feart.2019.00268

Wetting behavior of iron-carbon melt in silicates at mid-mantle pressures with implications for Earth's deep carbon cycle

 Junjie Dong1, 2,  Jie Li1* and Feng Zhu1, 3
  • 1University of Michigan, United States
  • 2Harvard University, United States
  • 3University of Hawaii at Manoa, United States

Metallic melt containing iron (Fe) and carbon (C) may be present at depths greater than 250 km inside the Earth. Depending on its wetting behavior, such dense melt may be trapped locally or drain into deep mantle and core. Here, we report experimental data on the wetting behavior of Fe-C melt in silicates at the conditions of Earth’s mid-mantle between 10 and 23 GPa and 1600 and 1800 ˚C. The measured dihedral angles of Fe-C melt in olivine, ringwoodite or bridgmanite and ferropericlase matrixes are 117±14°, 120±14° and 107±16° respectively, well above the critical value of 60° for complete wetting. The estimated percolation thresholds are at least 7% in volume, far exceeding the amount of metal in the mantle. Consequently, slab-derived Fe-C melt in the mid-mantle is expected to occur as isolated pockets and would not percolate through its silicate matrix.

Keywords: Dihedral angle, metallic melt, Bridgmanite, Percolation, Ultra-low velocity zones, Core growth

Received: 31 May 2019; Accepted: 30 Sep 2019.

Copyright: © 2019 Dong, Li and Zhu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Jie Li, University of Michigan, Ann Arbor, 48109, Michigan, United States, jackieli@umich.edu