Next Article in Journal
Rare Earth Element and Incompatible Trace Element Abundances in Emeralds Reveal Their Formation Environments
Next Article in Special Issue
Synthesis and Compressibility of Novel Nickel Carbide at Pressures of Earth’s Outer Core
Previous Article in Journal
Oxidation Behavior and Kinetics Parameters of a Lean Coal at Low Temperature Based on Different Oxygen Concentrations
Previous Article in Special Issue
Ni Doping: A Viable Route to Make Body-Centered-Cubic Fe Stable at Earth’s Inner Core
Article

Composition and Pressure Effects on Partitioning of Ferrous Iron in Iron-Rich Lower Mantle Heterogeneities

1
Earth and Planetary Science Laboratory, Institute for Condensed Matter Physics, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
2
Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI 48824, USA
3
CNRS, Institut de physique du globe de Paris, Université de Paris, F-75005 Paris, France
4
Center for Advanced Radiation Sources, University of Chicago, Argonne, IL 60439, USA
5
Interdisciplinary Center for Electron Microscopy, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
*
Author to whom correspondence should be addressed.
Academic Editor: Yamirka Rojas-Agramonte
Minerals 2021, 11(5), 512; https://doi.org/10.3390/min11050512
Received: 11 March 2021 / Revised: 28 April 2021 / Accepted: 6 May 2021 / Published: 12 May 2021
(This article belongs to the Special Issue Minerals under Extreme Conditions)
Both seismic observations of dense low shear velocity regions and models of magma ocean crystallization and mantle dynamics support enrichment of iron in Earth’s lowermost mantle. Physical properties of iron-rich lower mantle heterogeneities in the modern Earth depend on distribution of iron between coexisting lower mantle phases (Mg,Fe)O magnesiowüstite, (Mg,Fe)SiO3 bridgmanite, and (Mg,Fe)SiO3 post-perovskite. The partitioning of iron between these phases was investigated in synthetic ferrous-iron-rich olivine compositions (Mg0.55Fe0.45)2SiO4 and (Mg0.28Fe0.72)2SiO4 at lower mantle conditions ranging from 33–128 GPa and 1900–3000 K in the laser-heated diamond anvil cell. The resulting phase assemblages were characterized by a combination of in situ X-ray diffraction and ex situ transmission electron microscopy. The exchange coefficient between bridgmanite and magnesiowüstite decreases with pressure and bulk Fe# and increases with temperature. Thermodynamic modeling determines that incorporation and partitioning of iron in bridgmanite are explained well by excess volume associated with Mg-Fe exchange. Partitioning results are used to model compositions and densities of mantle phase assemblages as a function of pressure, FeO-content and SiO2-content. Unlike average mantle compositions, iron-rich compositions in the mantle exhibit negative dependence of density on SiO2-content at all mantle depths, an important finding for interpretation of deep lower mantle structures. View Full-Text
Keywords: iron partitioning; lower mantle; mantle heterogeneities; laser-heated diamond anvil cell; experimental petrology iron partitioning; lower mantle; mantle heterogeneities; laser-heated diamond anvil cell; experimental petrology
Show Figures

Figure 1

MDPI and ACS Style

Dorfman, S.M.; Nabiei, F.; Boukaré, C.-E.; Prakapenka, V.B.; Cantoni, M.; Badro, J.; Gillet, P. Composition and Pressure Effects on Partitioning of Ferrous Iron in Iron-Rich Lower Mantle Heterogeneities. Minerals 2021, 11, 512. https://doi.org/10.3390/min11050512

AMA Style

Dorfman SM, Nabiei F, Boukaré C-E, Prakapenka VB, Cantoni M, Badro J, Gillet P. Composition and Pressure Effects on Partitioning of Ferrous Iron in Iron-Rich Lower Mantle Heterogeneities. Minerals. 2021; 11(5):512. https://doi.org/10.3390/min11050512

Chicago/Turabian Style

Dorfman, Susannah M., Farhang Nabiei, Charles-Edouard Boukaré, Vitali B. Prakapenka, Marco Cantoni, James Badro, and Philippe Gillet. 2021. "Composition and Pressure Effects on Partitioning of Ferrous Iron in Iron-Rich Lower Mantle Heterogeneities" Minerals 11, no. 5: 512. https://doi.org/10.3390/min11050512

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop