Turbulent metal–silicate mixing, fragmentation, and equilibration in magma oceans
By R. Deguen, M. Landeau, P. Olson. 2014
139 citations recorded by the source corpus.
Abstract Much of the Earth was built by high-energy impacts of planetesimals and embryos, many of these impactors already differentiated, with metallic cores of their own. Geochemical data provide critical information on the timing of accretion and the prevailing physical conditions, but their interpretation depends critically on the degree of metal–silicate chemical equilibration during core–mantle differentiation, which is poorly constrained. Efficient equilibration requires that the large volumes of iron derived from impactor cores mix with molten silicates down to scales small enough to allow fast metal–silicate mass transfer. Here we use fluid dynamics experiments to show that large metal blobs falling in a magma ocean mix with the molten silicate through turbulent entrainment, with fragmentation into droplets eventually resulting from the entrainment process. In our experiments, fragmentation of the dense fluid occurs after falling a distance equal to 3–4 times its initial diameter, at which point a sizable volume of ambient fluid has already been entrained and mixed with the dense falling fluid. Contrary to previous assumptions, we demonstrate that fragmentation of the metallic phase into droplets may not be required for efficient equilibration: turbulent mixing, by drastically increasing the metal–silicate interfacial area, may result in fast equilibration even before fragmentation. Efficient re-equilibration is predicted for impactors of size small compared to the magma ocean depth. In contrast, much less re-equilibration is predicted for large impacts in situations where the impactor core diameter approaches the magma ocean thickness.
Subfields: Astronomy and Astrophysics, Atmospheric Science
View Paper: https://www.semanticscholar.org/paper/4716a1645cafa8970221028401f6dd295bce7d9f
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Astronomy and Astrophysics
In Atmospheric Science
Citations in the corpus
- Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion of water (2014, background): “ cores of small impactors may emulsify and equilibrate completely, the behaviour of the cores of large “giant” impactors remains uncertain (Dahl and Stevenson, 2010; Rubie et al., 2011; Samuel, 2012; Deguen et al., 2014). The degree to which metal equilibrates chemically in a magma ocean affects sid”