1
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Morard G, Hernandez JA, Pege C, Nagy C, Libon L, Lacquement A, Sokaras D, Lee HJ, Galtier E, Heimann P, Cunningham E, Glenzer SH, Vinci T, Prescher C, Boccato S, Chantel J, Merkel S, Zhang Y, Yang H, Wei X, Pandolfi S, Mao WL, Gleason AE, Shim SH, Alonso-Mori R, Ravasio A. Structural evolution of liquid silicates under conditions in Super-Earth interiors. Nat Commun 2024; 15:8483. [PMID: 39362851 PMCID: PMC11452200 DOI: 10.1038/s41467-024-51796-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 08/15/2024] [Indexed: 10/05/2024] Open
Abstract
Molten silicates at depth are crucial for planetary evolution, yet their local structure and physical properties under extreme conditions remain elusive due to experimental challenges. In this study, we utilize in situ X-ray diffraction (XRD) at the Matter in Extreme Conditions (MEC) end-station of the Linear Coherent Linac Source (LCLS) at SLAC National Accelerator Laboratory to investigate liquid silicates. Using an ultrabright X-ray source and a high-power optical laser, we probed the local atomic arrangement of shock-compressed liquid (Mg,Fe)SiO3 with varying Fe content, at pressures from 81(9) to 385(40) GPa. We compared these findings to ab initio molecular dynamics simulations under similar conditions. Results indicate continuous densification of the O-O and Mg-Si networks beyond Earth's interior pressure range, potentially altering melt properties at extreme conditions. This could have significant implications for early planetary evolution, leading to notable differences in differentiation processes between smaller rocky planets, such as Earth and Venus, and super-Earths, which are exoplanets with masses nearly three times that of Earth.
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Affiliation(s)
- Guillaume Morard
- ISTerre, Université Grenoble Alpes, CNRS, Grenoble, France.
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris, France.
| | | | - Clara Pege
- ISTerre, Université Grenoble Alpes, CNRS, Grenoble, France
| | - Charlotte Nagy
- ISTerre, Université Grenoble Alpes, CNRS, Grenoble, France
| | - Lélia Libon
- ISTerre, Université Grenoble Alpes, CNRS, Grenoble, France
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris, France
| | | | | | - Hae Ja Lee
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Eric Galtier
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Philip Heimann
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | | | | | - Tommaso Vinci
- LULI, Ecole Polytechnique, Sorbonne Université, Palaiseau, France
| | | | - Silvia Boccato
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris, France
| | - Julien Chantel
- Univ. Lille, CNRS, INRAE, Centrale Lille, UMR 8207-UMET-Unité Matériaux et Transformations, Lille, France
| | - Sébastien Merkel
- Univ. Lille, CNRS, INRAE, Centrale Lille, UMR 8207-UMET-Unité Matériaux et Transformations, Lille, France
| | - Yanyao Zhang
- Earth and Planetary Sciences, Stanford University, Stanford, CA, USA
| | - Hong Yang
- Earth and Planetary Sciences, Stanford University, Stanford, CA, USA
| | - Xuehui Wei
- School of Earth and Space Exploration, Arizona State University, Tempe, USA
| | - Silvia Pandolfi
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris, France
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Wendy L Mao
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Earth and Planetary Sciences, Stanford University, Stanford, CA, USA
| | - Arianna E Gleason
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Earth and Planetary Sciences, Stanford University, Stanford, CA, USA
| | - Sang Heon Shim
- School of Earth and Space Exploration, Arizona State University, Tempe, USA
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2
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Bajgain SK, Ashley AW, Mookherjee M, Ghosh DB, Karki BB. Insights into magma ocean dynamics from the transport properties of basaltic melt. Nat Commun 2022; 13:7590. [PMID: 36481757 PMCID: PMC9731987 DOI: 10.1038/s41467-022-35171-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 11/17/2022] [Indexed: 12/13/2022] Open
Abstract
The viscosity of magma plays a crucial role in the dynamics of the Earth: from the crystallization of a magma ocean during its initial stages to modern-day volcanic processes. However, the pressure-dependence behavior of viscosity at high pressure remains controversial. In this study, we report the results of first-principles molecular dynamics simulations of basaltic melt to show that the melt viscosity increases upon compression along each isotherm for the entire lower mantle after showing minima at ~6 GPa. However, elevated temperatures of the magma ocean translate to a narrow range of viscosity, i.e., 0.01-0.03 Pa.s. This low viscosity implies that the crystallization of the magma ocean could be complete within a few million years. These results also suggest that the crystallization of the magma ocean is likely to be fractional, thus supporting the hypothesis that present-day mantle heterogeneities could have been generated during the early crystallization of the primitive mantle.
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Affiliation(s)
- Suraj K Bajgain
- Earth Materials Laboratory, Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, USA.
- Department of Geology, School of Natural Resources & Environment, Lake Superior State University, Sault Ste Marie, MI, USA.
| | - Aaron Wolfgang Ashley
- Earth Materials Laboratory, Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, USA
| | - Mainak Mookherjee
- Earth Materials Laboratory, Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, USA.
| | - Dipta B Ghosh
- School of Electrical Engineering and Computer Science, Department of Geology and Geophysics, Center for Computation and Technology, Louisiana State University, Baton Rouge, LA, USA
| | - Bijaya B Karki
- School of Electrical Engineering and Computer Science, Department of Geology and Geophysics, Center for Computation and Technology, Louisiana State University, Baton Rouge, LA, USA.
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3
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Fei Y, Seagle CT, Townsend JP, McCoy CA, Boujibar A, Driscoll P, Shulenburger L, Furnish MD. Melting and density of MgSiO 3 determined by shock compression of bridgmanite to 1254GPa. Nat Commun 2021; 12:876. [PMID: 33563984 PMCID: PMC7873221 DOI: 10.1038/s41467-021-21170-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/11/2021] [Indexed: 12/03/2022] Open
Abstract
The essential data for interior and thermal evolution models of the Earth and super-Earths are the density and melting of mantle silicate under extreme conditions. Here, we report an unprecedently high melting temperature of MgSiO3 at 500 GPa by direct shockwave loading of pre-synthesized dense MgSiO3 (bridgmanite) using the Z Pulsed Power Facility. We also present the first high-precision density data of crystalline MgSiO3 to 422 GPa and 7200 K and of silicate melt to 1254 GPa. The experimental density measurements support our density functional theory based molecular dynamics calculations, providing benchmarks for theoretical calculations under extreme conditions. The excellent agreement between experiment and theory provides a reliable reference density profile for super-Earth mantles. Furthermore, the observed upper bound of melting temperature, 9430 K at 500 GPa, provides a critical constraint on the accretion energy required to melt the mantle and the prospect of driving a dynamo in massive rocky planets.
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Affiliation(s)
- Yingwei Fei
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA.
| | | | | | - Chad A McCoy
- Sandia National Laboratories, Albuquerque, NM, USA
| | - Asmaa Boujibar
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - Peter Driscoll
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
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4
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Lichtenberg T, Bower DJ, Hammond M, Boukrouche R, Sanan P, Tsai S, Pierrehumbert RT. Vertically Resolved Magma Ocean-Protoatmosphere Evolution: H 2, H 2O, CO 2, CH 4, CO, O 2, and N 2 as Primary Absorbers. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2021; 126:e2020JE006711. [PMID: 33777608 PMCID: PMC7988593 DOI: 10.1029/2020je006711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
The earliest atmospheres of rocky planets originate from extensive volatile release during magma ocean epochs that occur during assembly of the planet. These establish the initial distribution of the major volatile elements between different chemical reservoirs that subsequently evolve via geological cycles. Current theoretical techniques are limited in exploring the anticipated range of compositional and thermal scenarios of early planetary evolution, even though these are of prime importance to aid astronomical inferences on the environmental context and geological history of extrasolar planets. Here, we present a coupled numerical framework that links an evolutionary, vertically resolved model of the planetary silicate mantle with a radiative-convective model of the atmosphere. Using this method, we investigate the early evolution of idealized Earth-sized rocky planets with end-member, clear-sky atmospheres dominated by either H2, H2O, CO2, CH4, CO, O2, or N2. We find central metrics of early planetary evolution, such as energy gradient, sequence of mantle solidification, surface pressure, or vertical stratification of the atmosphere, to be intimately controlled by the dominant volatile and outgassing history of the planet. Thermal sequences fall into three general classes with increasing cooling timescale: CO, N2, and O2 with minimal effect, H2O, CO2, and CH4 with intermediate influence, and H2 with several orders of magnitude increase in solidification time and atmosphere vertical stratification. Our numerical experiments exemplify the capabilities of the presented modeling framework and link the interior and atmospheric evolution of rocky exoplanets with multiwavelength astronomical observations.
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Affiliation(s)
- Tim Lichtenberg
- Atmospheric, Oceanic and Planetary Physics, Department of PhysicsUniversity of OxfordOxfordUK
| | - Dan J. Bower
- Center for Space and HabitabilityUniversity of BernBernSwitzerland
| | - Mark Hammond
- Department of the Geophysical SciencesUniversity of ChicagoChicagoILUSA
| | - Ryan Boukrouche
- Atmospheric, Oceanic and Planetary Physics, Department of PhysicsUniversity of OxfordOxfordUK
| | - Patrick Sanan
- Institute of Geophysics, Department of Earth SciencesETH ZurichZurichSwitzerland
| | - Shang‐Min Tsai
- Atmospheric, Oceanic and Planetary Physics, Department of PhysicsUniversity of OxfordOxfordUK
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5
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Morard G, Hernandez JA, Guarguaglini M, Bolis R, Benuzzi-Mounaix A, Vinci T, Fiquet G, Baron MA, Shim SH, Ko B, Gleason AE, Mao WL, Alonso-Mori R, Lee HJ, Nagler B, Galtier E, Sokaras D, Glenzer SH, Andrault D, Garbarino G, Mezouar M, Schuster AK, Ravasio A. In situ X-ray diffraction of silicate liquids and glasses under dynamic and static compression to megabar pressures. Proc Natl Acad Sci U S A 2020; 117:11981-11986. [PMID: 32414927 PMCID: PMC7275726 DOI: 10.1073/pnas.1920470117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Properties of liquid silicates under high-pressure and high-temperature conditions are critical for modeling the dynamics and solidification mechanisms of the magma ocean in the early Earth, as well as for constraining entrainment of melts in the mantle and in the present-day core-mantle boundary. Here we present in situ structural measurements by X-ray diffraction of selected amorphous silicates compressed statically in diamond anvil cells (up to 157 GPa at room temperature) or dynamically by laser-generated shock compression (up to 130 GPa and 6,000 K along the MgSiO3 glass Hugoniot). The X-ray diffraction patterns of silicate glasses and liquids reveal similar characteristics over a wide pressure and temperature range. Beyond the increase in Si coordination observed at 20 GPa, we find no evidence for major structural changes occurring in the silicate melts studied up to pressures and temperatures exceeding Earth's core mantle boundary conditions. This result is supported by molecular dynamics calculations. Our findings reinforce the widely used assumption that the silicate glasses studies are appropriate structural analogs for understanding the atomic arrangement of silicate liquids at these high pressures.
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Affiliation(s)
- Guillaume Morard
- Sorbonne Université, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Museum National d'Histoire Naturelle, UMR CNRS 7590, 75005 Paris, France;
- Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, Institut de Recherche pour le Développement, Institut Français des Sciences et Technologies des Transports, de L'aménagement et des Réseaux, ISTerre, 38000 Grenoble, France
| | - Jean-Alexis Hernandez
- Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, Commissariat à l'Energie Atomique, Sorbonne Université, 91128 Palaiseau, France
- Centre for Earth Evolution and Dynamics, University of Oslo, N-0315 Oslo, Norway
| | - Marco Guarguaglini
- Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, Commissariat à l'Energie Atomique, Sorbonne Université, 91128 Palaiseau, France
| | - Riccardo Bolis
- Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, Commissariat à l'Energie Atomique, Sorbonne Université, 91128 Palaiseau, France
| | - Alessandra Benuzzi-Mounaix
- Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, Commissariat à l'Energie Atomique, Sorbonne Université, 91128 Palaiseau, France
| | - Tommaso Vinci
- Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, Commissariat à l'Energie Atomique, Sorbonne Université, 91128 Palaiseau, France
| | - Guillaume Fiquet
- Sorbonne Université, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Museum National d'Histoire Naturelle, UMR CNRS 7590, 75005 Paris, France
| | - Marzena A Baron
- Sorbonne Université, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Museum National d'Histoire Naturelle, UMR CNRS 7590, 75005 Paris, France
| | - Sang Heon Shim
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287
| | - Byeongkwan Ko
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287
| | - Arianna E Gleason
- Geological Sciences, Stanford University, Stanford, CA 94305-2115
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Wendy L Mao
- Geological Sciences, Stanford University, Stanford, CA 94305-2115
| | | | - Hae Ja Lee
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Bob Nagler
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Eric Galtier
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | | | | | - Denis Andrault
- Université Clermont Auvergne, CNRS, Institut de Recherche pour le Développement, Observatoire Physique du Globe de Clermont-Ferrand, Laboratoire Magmas et Volcans, F-63000 Clermont-Ferrand, France
| | | | - Mohamed Mezouar
- European Synchrotron Radiation Facility, 38000 Grenoble, France
| | - Anja K Schuster
- Helmholtz-Zentrum Dresden Rossendorf, D-01328 Dresden, Germany
| | - Alessandra Ravasio
- Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, Commissariat à l'Energie Atomique, Sorbonne Université, 91128 Palaiseau, France
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6
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Lin W, Murillo MS, Feng Y. Universal relationship of compression shocks in two-dimensional Yukawa systems. Phys Rev E 2020; 101:013203. [PMID: 32069524 DOI: 10.1103/physreve.101.013203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Using molecular dynamical simulations, compressional shocks in two-dimensional (2D) dusty plasmas are quantitatively investigated under various conditions. A universal relationship between the thermal and the drift velocities after shocks is discovered in 2D Yukawa systems. Using the equation of state of 2D Yukawa liquids, and the obtained pressure from the Rankine-Hugoniot relation, an analytical relation between the thermal and the drift velocities is derived, which well agrees with the discovered universal relationship for various conditions.
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Affiliation(s)
- Wei Lin
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - M S Murillo
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, Michigan 48824, USA
| | - Yan Feng
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
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7
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Tracy SJ, Turneaure SJ, Duffy TS. In situ X-Ray Diffraction of Shock-Compressed Fused Silica. PHYSICAL REVIEW LETTERS 2018; 120:135702. [PMID: 29694206 DOI: 10.1103/physrevlett.120.135702] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Indexed: 06/08/2023]
Abstract
Because of its widespread applications in materials science and geophysics, SiO_{2} has been extensively examined under shock compression. Both quartz and fused silica transform through a so-called "mixed-phase region" to a dense, low compressibility high-pressure phase. For decades, the nature of this phase has been a subject of debate. Proposed structures include crystalline stishovite, another high-pressure crystalline phase, or a dense amorphous phase. Here we use plate-impact experiments and pulsed synchrotron x-ray diffraction to examine the structure of fused silica shock compressed to 63 GPa. In contrast to recent laser-driven compression experiments, we find that fused silica adopts a dense amorphous structure at 34 GPa and below. When compressed above 34 GPa, fused silica transforms to untextured polycrystalline stishovite. Our results can explain previously ambiguous features of the shock-compression behavior of fused silica and are consistent with recent molecular dynamics simulations. Stishovite grain sizes are estimated to be ∼5-30 nm for compression over a few hundred nanosecond time scale.
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Affiliation(s)
- Sally June Tracy
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA
| | - Stefan J Turneaure
- Institute for Shock Physics, Washington State University, Pullman, Washington 99164-2816, USA
| | - Thomas S Duffy
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA
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8
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Di Paola C, P Brodholt J. Modeling the melting of multicomponent systems: the case of MgSiO3 perovskite under lower mantle conditions. Sci Rep 2016; 6:29830. [PMID: 27444854 PMCID: PMC4956746 DOI: 10.1038/srep29830] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/22/2016] [Indexed: 01/11/2023] Open
Abstract
Knowledge of the melting properties of materials, especially at extreme pressure conditions, represents a long-standing scientific challenge. For instance, there is currently considerable uncertainty over the melting temperatures of the high-pressure mantle mineral, bridgmanite (MgSiO3-perovskite), with current estimates of the melting T at the base of the mantle ranging from 4800 K to 8000 K. The difficulty with experimentally measuring high pressure melting temperatures has motivated the use of ab initio methods, however, melting is a complex multi-scale phenomenon and the timescale for melting can be prohibitively long. Here we show that a combination of empirical and ab-initio molecular dynamics calculations can be used to successfully predict the melting point of multicomponent systems, such as MgSiO3 perovskite. We predict the correct low-pressure melting T, and at high-pressure we show that the melting temperature is only 5000 K at 120 GPa, a value lower than nearly all previous estimates. In addition, we believe that this strategy is of general applicability and therefore suitable for any system under physical conditions where simpler models fail.
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Affiliation(s)
- Cono Di Paola
- Department of Earth Sciences, University College London, WC1E 6BT London United Kingdom
| | - John P Brodholt
- Department of Earth Sciences, University College London, WC1E 6BT London United Kingdom
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9
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Sakai T, Dekura H, Hirao N. Experimental and theoretical thermal equations of state of MgSiO3 post-perovskite at multi-megabar pressures. Sci Rep 2016; 6:22652. [PMID: 26948855 PMCID: PMC4780068 DOI: 10.1038/srep22652] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/18/2016] [Indexed: 11/17/2022] Open
Abstract
The MgSiO3 post-perovskite phase is the most abundant silicate phase in a super-Earth’s mantle, although it only exists within the Earth’s lowermost mantle. In this study, we established the thermal equation of state (EoS) of the MgSiO3 post-perovskite phase, which were determined by using both laser-heated diamond anvil cell and density-functional theoretical techniques, within a multi-megabar pressure range, corresponding to the conditions of a super-Earth’s mantle. The Keane and AP2 EoS models were adopted for the first time to extract meaningful physical properties. The experimentally determined Grüneisen parameter, which is one of the thermal EoS parameters, and its volume dependence were found to be consistent with their theoretically obtained values. This reduced the previously reported discrepancy observed between experiment and theory. Both the experimental and theoretical EoS were also found to be in very good agreement for volumes at pressures and temperatures of up to 300 GPa and 5000 K, respectively. Our newly developed EoS should be applicable to a super-Earth’s mantle, as well as the Earth’s core-mantle boundary region.
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Affiliation(s)
- Takeshi Sakai
- Geodynamics Research Center, Ehime University, Matsuyama 790-8577, Japan
| | - Haruhiko Dekura
- Geodynamics Research Center, Ehime University, Matsuyama 790-8577, Japan
| | - Naohisa Hirao
- Japan Synchrotron Radiation Research Institute, Hyogo 679-5198, Japan
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10
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Abstract
One key for understanding the stratification in the deep mantle lies in the determination of the density and structure of matter at high pressures, as well as the density contrast between solid and liquid silicate phases. Indeed, the density contrast is the main control on the entrainment or settlement of matter and is of fundamental importance for understanding the past and present dynamic behavior of the deepest part of the Earth's mantle. Here, we adapted the X-ray absorption method to the small dimensions of the diamond anvil cell, enabling density measurements of amorphous materials to unprecedented conditions of pressure. Our density data for MgSiO3 glass up to 127 GPa are considerably higher than those previously derived from Brillouin spectroscopy but validate recent ab initio molecular dynamics simulations. A fourth-order Birch-Murnaghan equation of state reproduces our experimental data over the entire pressure regime of the mantle. At the core-mantle boundary (CMB) pressure, the density of MgSiO3 glass is 5.48 ± 0.18 g/cm(3), which is only 1.6% lower than that of MgSiO3 bridgmanite at 5.57 g/cm(3), i.e., they are the same within the uncertainty. Taking into account the partitioning of iron into the melt, we conclude that melts are denser than the surrounding solid phases in the lowermost mantle and that melts will be trapped above the CMB.
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11
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Sleep NH, Zahnle KJ, Lupu RE. Terrestrial aftermath of the Moon-forming impact. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130172. [PMID: 25114303 DOI: 10.1098/rsta.2013.0172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Much of the Earth's mantle was melted in the Moon-forming impact. Gases that were not partially soluble in the melt, such as water and CO2, formed a thick, deep atmosphere surrounding the post-impact Earth. This atmosphere was opaque to thermal radiation, allowing heat to escape to space only at the runaway greenhouse threshold of approximately 100 W m(-2). The duration of this runaway greenhouse stage was limited to approximately 10 Myr by the internal energy and tidal heating, ending with a partially crystalline uppermost mantle and a solid deep mantle. At this point, the crust was able to cool efficiently and solidified at the surface. After the condensation of the water ocean, approximately 100 bar of CO2 remained in the atmosphere, creating a solar-heated greenhouse, while the surface cooled to approximately 500 K. Almost all this CO2 had to be sequestered by subduction into the mantle by 3.8 Ga, when the geological record indicates the presence of life and hence a habitable environment. The deep CO2 sequestration into the mantle could be explained by a rapid subduction of the old oceanic crust, such that the top of the crust would remain cold and retain its CO2. Kinematically, these episodes would be required to have both fast subduction (and hence seafloor spreading) and old crust. Hadean oceanic crust that formed from hot mantle would have been thicker than modern crust, and therefore only old crust underlain by cool mantle lithosphere could subduct. Once subduction started, the basaltic crust would turn into dense eclogite, increasing the rate of subduction. The rapid subduction would stop when the young partially frozen crust from the rapidly spreading ridge entered the subduction zone.
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Affiliation(s)
- Norman H Sleep
- Department of Geophysics, Stanford University, Stanford, CA 94305, USA
| | | | - Roxana E Lupu
- NASA Ames Research Center, Moffett Field, CA 94035, USA
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12
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Thomas CW, Liu Q, Agee CB, Asimow PD, Lange RA. Multi-technique equation of state for Fe2SiO4melt and the density of Fe-bearing silicate melts from 0 to 161 GPa. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jb009403] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Solid-liquid iron partitioning in Earth's deep mantle. Nature 2012; 487:354-7. [PMID: 22810700 DOI: 10.1038/nature11294] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 05/31/2012] [Indexed: 11/09/2022]
Abstract
Melting processes in the deep mantle have important implications for the origin of the deep-derived plumes believed to feed hotspot volcanoes such as those in Hawaii. They also provide insight into how the mantle has evolved, geochemically and dynamically, since the formation of Earth. Melt production in the shallow mantle is quite well understood, but deeper melting near the core-mantle boundary remains controversial. Modelling the dynamic behaviour of deep, partially molten mantle requires knowledge of the density contrast between solid and melt fractions. Although both positive and negative melt buoyancies can produce major chemical segregation between different geochemical reservoirs, each type of buoyancy yields drastically different geodynamical models. Ascent or descent of liquids in a partially molten deep mantle should contribute to surface volcanism or production of a deep magma ocean, respectively. We investigated phase relations in a partially molten chondritic-type material under deep-mantle conditions. Here we show that the iron partition coefficient between aluminium-bearing (Mg,Fe)SiO(3) perovskite and liquid is between 0.45 and 0.6, so iron is not as incompatible with deep-mantle minerals as has been reported previously. Calculated solid and melt density contrasts suggest that melt generated at the core-mantle boundary should be buoyant, and hence should segregate upwards. In the framework of the magma oceans induced by large meteoritic impacts on early Earth, our results imply that the magma crystallization should push the liquids towards the surface and form a deep solid residue depleted in incompatible elements.
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Spaulding DK, McWilliams RS, Jeanloz R, Eggert JH, Celliers PM, Hicks DG, Collins GW, Smith RF. Evidence for a phase transition in silicate melt at extreme pressure and temperature conditions. PHYSICAL REVIEW LETTERS 2012; 108:065701. [PMID: 22401087 DOI: 10.1103/physrevlett.108.065701] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Indexed: 05/31/2023]
Abstract
Laser-driven shock compression experiments reveal the presence of a phase transition in MgSiO(3) over the pressure-temperature range 300-400 GPa and 10 000-16 000 K, with a positive Clapeyron slope and a volume change of ∼6.3 (±2.0) percent. The observations are most readily interpreted as an abrupt liquid-liquid transition in a silicate composition representative of terrestrial planetary mantles, implying potentially significant consequences for the thermal-chemical evolution of extrasolar planetary interiors. In addition, the present results extend the Hugoniot equation of state of MgSiO(3) single crystal and glass to 950 GPa.
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Affiliation(s)
- D K Spaulding
- Department of Earth and Planetary Science, University of California, Berkeley, California 94720-4767, USA
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Metsue A, Tsuchiya T. Lattice dynamics and thermodynamic properties of (Mg,Fe2+)SiO3postperovskite. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jb008018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Asimow PD, Ahrens TJ. Shock compression of liquid silicates to 125 GPa: The anorthite-diopside join. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jb007145] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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