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Fei H, Ballmer MD, Faul U, Walte N, Cao W, Katsura T. Variation in bridgmanite grain size accounts for the mid-mantle viscosity jump. Nature 2023; 620:794-799. [PMID: 37407826 PMCID: PMC10447242 DOI: 10.1038/s41586-023-06215-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/12/2023] [Indexed: 07/07/2023]
Abstract
A viscosity jump of one to two orders of magnitude in the lower mantle of Earth at 800-1,200-km depth is inferred from geoid inversions and slab-subducting speeds. This jump is known as the mid-mantle viscosity jump1,2. The mid-mantle viscosity jump is a key component of lower-mantle dynamics and evolution because it decelerates slab subduction3, accelerates plume ascent4 and inhibits chemical mixing5. However, because phase transitions of the main lower-mantle minerals do not occur at this depth, the origin of the viscosity jump remains unknown. Here we show that bridgmanite-enriched rocks in the deep lower mantle have a grain size that is more than one order of magnitude larger and a viscosity that is at least one order of magnitude higher than those of the overlying pyrolitic rocks. This contrast is sufficient to explain the mid-mantle viscosity jump1,2. The rapid growth in bridgmanite-enriched rocks at the early stage of the history of Earth and the resulting high viscosity account for their preservation against mantle convection5-7. The high Mg:Si ratio of the upper mantle relative to chondrites8, the anomalous 142Nd:144Nd, 182W:184W and 3He:4He isotopic ratios in hot-spot magmas9,10, the plume deflection4 and slab stagnation in the mid-mantle3 as well as the sparse observations of seismic anisotropy11,12 can be explained by the long-term preservation of bridgmanite-enriched rocks in the deep lower mantle as promoted by their fast grain growth.
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Affiliation(s)
- Hongzhan Fei
- Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany.
- Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou, China.
| | - Maxim D Ballmer
- Department of Earth Sciences, University College London, London, UK
| | - Ulrich Faul
- Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nicolas Walte
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Garching, Germany
| | - Weiwei Cao
- Conditions Extrêmes et Matériaux: Haute Température et Irradiation (CEMHTI), Orléans, France
| | - Tomoo Katsura
- Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany
- Center for High Pressure Science and Technology Advanced Research, Beijing, China
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2
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Tsujino N, Yamazaki D, Nishihara Y, Yoshino T, Higo Y, Tange Y. Viscosity of bridgmanite determined by in situ stress and strain measurements in uniaxial deformation experiments. SCIENCE ADVANCES 2022; 8:eabm1821. [PMID: 35353572 PMCID: PMC8967219 DOI: 10.1126/sciadv.abm1821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
To understand mantle dynamics, it is important to determine the rheological properties of bridgmanite, the dominant mineral in Earth's mantle. Nevertheless, experimental data on the viscosity of bridgmanite are quite limited due to experimental difficulties. Here, we report viscosity and deformation mechanism maps of bridgmanite at the uppermost lower mantle conditions obtained through in situ stress-strain measurements of bridgmanite using deformation apparatuses with the Kawai-type cell. Bridgmanite would be the hardest among mantle constituent minerals even under nominally dry conditions in the dislocation creep region, consistent with the observation that the lower mantle is the hardest layer. Deformation mechanism maps of bridgmanite indicate that grain size of bridgmanite and stress conditions at top of the lower mantle would be several millimeters and ~105 Pa to realize viscosity of 1021-22 Pa·s, respectively. This grain size of bridgmanite suggests that the main part of the lower mantle is isolated from the convecting mantle as primordial reservoirs.
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Affiliation(s)
- Noriyoshi Tsujino
- Institute for Planetary Materials, Okayama University, 27 Yamada, Misasa, Tottori 682-0193, Japan
| | - Daisuke Yamazaki
- Institute for Planetary Materials, Okayama University, 27 Yamada, Misasa, Tottori 682-0193, Japan
| | - Yu Nishihara
- Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Takashi Yoshino
- Institute for Planetary Materials, Okayama University, 27 Yamada, Misasa, Tottori 682-0193, Japan
| | - Yuji Higo
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Yoshinori Tange
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
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3
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The role of diffusion-driven pure climb creep on the rheology of bridgmanite under lower mantle conditions. Sci Rep 2019; 9:2053. [PMID: 30765772 PMCID: PMC6376055 DOI: 10.1038/s41598-018-38449-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/17/2018] [Indexed: 11/18/2022] Open
Abstract
The viscosity of Earth’s lower mantle is poorly constrained due to the lack of knowledge on some fundamental variables that affect the deformation behaviour of its main mineral phases. This study focuses on bridgmanite, the main lower mantle constituent, and assesses its rheology by developing an approach based on mineral physics. Following and revising the recent advances in this field, pure climb creep controlled by diffusion is identified as the key mechanism driving deformation in bridgmanite. The strain rates of this phase under lower mantle pressures, temperatures and stresses are thus calculated by constraining diffusion and implementing a creep theoretical model. The viscosity of MgSiO3 bridgmanite resulting from pure climb creep is consequently evaluated and compared with the viscosity profiles available from the literature. We show that the inferred variability of viscosity in these profiles can be fully accounted for with the chosen variables of our calculation, e.g., diffusion coefficients, vacancy concentrations and applied stresses. A refinement of these variables is advocated in order to further constrain viscosity and match the observables.
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Desissa TD, Kanas N, Singh SP, Wiik K, Einarsrud MA, Norby T. Chemical tracer diffusion of Sr and Co in polycrystalline Ca-deficient CaMnO3−δwith CaMn2O4precipitates. Phys Chem Chem Phys 2018; 20:2754-2760. [DOI: 10.1039/c7cp07471a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Enhanced grain boundary diffusivity on B-site of perovskite CaMnO3with CaMn2O4precipitates determines operational window of n-type oxide for thermoelectrics.
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Affiliation(s)
- Temesgen D. Desissa
- Department of Chemistry
- Centre for Materials Science and Nanotechnology
- University of Oslo
- FERMiO
- NO-0349 Oslo
| | - Nikola Kanas
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- NO-7491 Trondheim
- Norway
| | - Sathya P. Singh
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- NO-7491 Trondheim
- Norway
| | - Kjell Wiik
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- NO-7491 Trondheim
- Norway
| | - Mari-Ann Einarsrud
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- NO-7491 Trondheim
- Norway
| | - Truls Norby
- Department of Chemistry
- Centre for Materials Science and Nanotechnology
- University of Oslo
- FERMiO
- NO-0349 Oslo
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6
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Fei H, Yamazaki D, Sakurai M, Miyajima N, Ohfuji H, Katsura T, Yamamoto T. A nearly water-saturated mantle transition zone inferred from mineral viscosity. SCIENCE ADVANCES 2017; 3:e1603024. [PMID: 28630912 PMCID: PMC5462500 DOI: 10.1126/sciadv.1603024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/10/2017] [Indexed: 06/14/2023]
Abstract
An open question for solid-earth scientists is the amount of water in Earth's interior. The uppermost mantle and lower mantle contain little water because their dominant minerals, olivine and bridgmanite, have limited water storage capacity. In contrast, the mantle transition zone (MTZ) at a depth of 410 to 660 km is considered to be a potential water reservoir because its dominant minerals, wadsleyite and ringwoodite, can contain large amounts of water [up to 3 weight % (wt %)]. However, the actual amount of water in the MTZ is unknown. Given that water incorporated into mantle minerals can lower their viscosity, we evaluate the water content of the MTZ by measuring dislocation mobility, a property that is inversely proportional to viscosity, as a function of temperature and water content in ringwoodite and bridgmanite. We find that dislocation mobility in bridgmanite is faster by two orders of magnitude than in anhydrous ringwoodite but 1.5 orders of magnitude slower than in water-saturated ringwoodite. To fit the observed mantle viscosity profiles, ringwoodite in the MTZ should contain 1 to 2 wt % water. The MTZ should thus be nearly water-saturated globally.
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Affiliation(s)
- Hongzhan Fei
- Institute for Study of the Earth’s Interior, Okayama University, Misasa, Tottori 682-0193, Japan
- Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth D95440, Germany
| | - Daisuke Yamazaki
- Institute for Study of the Earth’s Interior, Okayama University, Misasa, Tottori 682-0193, Japan
| | - Moe Sakurai
- Institute for Study of the Earth’s Interior, Okayama University, Misasa, Tottori 682-0193, Japan
- Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551, Japan
| | | | - Hiroaki Ohfuji
- Geodynamics Research Center, Ehime University, Matsuyama 790-8577, Japan
| | - Tomoo Katsura
- Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth D95440, Germany
| | - Takafumi Yamamoto
- Department of Earth and Planetary Systems Science, Hiroshima University, Hiroshima 739-8526, Japan
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Sažinas R, Sakaguchi I, Hasle I, Polfus JM, Haugsrud R, Einarsrud MA, Grande T. Tracer diffusion of96Zr and134Ba in polycrystalline BaZrO3. Phys Chem Chem Phys 2017; 19:21878-21886. [DOI: 10.1039/c7cp04039c] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tracer diffusion revealed that the diffusion of Ba is faster than that of Zr in BaZrO3and the diffusion mechanism is through Ba vacancies.
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Affiliation(s)
- Rokas Sažinas
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- NO-7491
- Trondheim
- Norway
| | - Isao Sakaguchi
- Research Center for Functional Materials
- National Institute for Materials Science
- 1-1 Namiki
- Tsukuba 305-0044
- Japan
| | - Ida Hasle
- Centre for Materials Science and Nanotechnology (SMN)
- FERMiO
- Department of Chemistry
- University of Oslo
- NO-0349 Oslo
| | | | - Reidar Haugsrud
- Centre for Materials Science and Nanotechnology (SMN)
- FERMiO
- Department of Chemistry
- University of Oslo
- NO-0349 Oslo
| | - Mari-Ann Einarsrud
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- NO-7491
- Trondheim
- Norway
| | - Tor Grande
- Department of Materials Science and Engineering
- NTNU Norwegian University of Science and Technology
- NO-7491
- Trondheim
- Norway
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Kubicek M, Rupp GM, Huber S, Penn A, Opitz AK, Bernardi J, Stöger-Pollach M, Hutter H, Fleig J. Cation diffusion in La0.6Sr0.4CoO3−δ below 800 °C and its relevance for Sr segregation. Phys Chem Chem Phys 2014; 16:2715-26. [DOI: 10.1039/c3cp51906f] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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