Iron diapirs entrain silicates to the core and initiate thermochemical plumes

• Published in: Nature communications Vol. 9; no. 1; p. 71
• Main Authors: Fleck, J. R., Rains, C. L., Weeraratne, D. S., Nguyen, C. T., Brand, D. M., Klein, S. M., McGehee, J. M., Rincon, J. M., Martinez, C., Olson, P. L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04-01-2018; Nature Publishing Group; Nature Portfolio
• Subjects: 704/2151/123; 704/445/123; Deposition; Diapirs; Earth mantle; Experiments; Gallium; Gravitation; Gravitational instability; Gravity; High pressure; Humanities and Social Sciences; Iron; Laboratories; Metals; Meteors & meteorites; Microprocessors; multidisciplinary; Oceans; Physical properties; Planetary interiors; Plumes; Rheology; Scaling; Science; Science (multidisciplinary); Silica; Silicates; Taylor instability; Upper mantle; Viscosity; Volatiles; Volcanic activity
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02503-2

Segregation of the iron core from rocky silicates is a massive evolutionary event in planetary accretion, yet the process of metal segregation remains obscure, due to obstacles in simulating the extreme physical properties of liquid iron and silicates at finite length scales. We present new experimental results studying gravitational instability of an emulsified liquid gallium layer, initially at rest at the interface between two glucose solutions. Metal settling coats liquid metal drops with a film of low density material. The emulsified metal pond descends as a coherent Rayleigh−Taylor instability with a trailing fluid-filled conduit. Scaling to planetary interiors and high pressure mineral experiments indicates that molten silicates and volatiles are entrained toward the iron core and initiate buoyant thermochemical plumes that later oxidize and hydrate the upper mantle. Surface volcanism from thermochemical plumes releases oxygen and volatiles linking atmospheric growth to the Earth’s mantle and core processes.
During planetary formation segregation of an iron core from rocky silicates takes place. Here, the authors use analogue fluid experiments show that iron diapirs entrain volatiles and silicates to the Earth’s core and initiate buoyant thermochemical plumes to reoxidize and hydrate the upper mantle and atmosphere.