Experimental Constraints on Ferropericlase (Mg, Fe)O Melt Viscosity Up to 70 GPa

Abstract

During Earth's accretion, Earth's mantle is expected to have been a magma ocean due to large impacts. As such, properties of molten mantle materials are key to understanding Earth's thermochemical evolution. However, due to experimental challenges, transport properties at lower mantle pressures, particularly viscosity, are poorly constrained for mantle melts. In this study, we use quenched dendritic textures to estimate melt viscosities at high pressures for (Mg, Fe)O ferropericlase, one of the major components of the mantle. We find that the viscosity of (Mg, Fe)O melt near liquidus temperatures is 10 À3-10 À2 Pa s over the pressure range of 3-70 GPa, which is~1-2 orders of magnitude lower than previous results for Si-rich melts at similar conditions. This may have implications for magma ocean cooling and thermochemical evolution of the mantle.

The metal–silicate partitioning of carbon during Earth's accretion and its distribution in the early solar system

“…This means that equilibrium carbon partitioning was also achieved because carbon diffusion in liquid metal is about 2.5 times faster than silicon diffusion (Rebaza et al, 2021). Press experiments (LVP, data from Ito et al, 1995;Gessmann C. and Rubie, 1998;Corgne et al, 2008;Mann et al, 2009;Siebert et al, 2011;Tsuno et al, 2013;, Diamond Anvil Cell experiments (DAC, data from Badro et al, 2018;Bouhifd and Jephcoat, 2011;Chidester et al, 2017;Du et al, 2017;Jackson et al, 2018 and this study.…”

Formation of deep mantle heterogeneities through basal exsolution contaminated magma ocean

“…Several studies have proposed that as Earth cools, light elements such as Mg 23,24,30,31 , Si, and O 26 become saturated in the core and precipitate in the forms of SiO 2 and MgO. The high melting points of MgO and SiO 2 , i.e., around 8000 K and 6000 K at the core-mantle boundary (CMB), respectively [32][33][34][35] , indicate that these precipitates occur as crystalline solids.…”