1
|
Zhang L, Chen Y, Yang Z, Liu L, Yang Y, Dalladay-Simpson P, Wang J, Mao HK. Pressure stabilizes ferrous iron in bridgmanite under hydrous deep lower mantle conditions. Nat Commun 2024; 15:4333. [PMID: 38773099 PMCID: PMC11109188 DOI: 10.1038/s41467-024-48665-8] [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: 06/19/2023] [Accepted: 05/09/2024] [Indexed: 05/23/2024] Open
Abstract
Earth's lower mantle is a potential water reservoir. The physical and chemical properties of the region are in part controlled by the Fe3+/ΣFe ratio and total iron content in bridgmanite. However, the water effect on the chemistry of bridgmanite remains unclear. We carry out laser-heated diamond anvil cell experiments under hydrous conditions and observe dominant Fe2+ in bridgmanite (Mg, Fe)SiO3 above 105 GPa under the normal geotherm conditions corresponding to depth > 2300 km, whereas Fe3+-rich bridgmanite is obtained at lower pressures. We further observe FeO in coexistence with hydrous NiAs-type SiO2 under similar conditions, indicating that the stability of ferrous iron is a combined result of H2O effect and high pressure. The stability of ferrous iron in bridgmanite under hydrous conditions would provide an explanation for the nature of the low-shear-velocity anomalies in the deep lower mantle. In addition, entrainment from a hydrous dense layer may influence mantle plume dynamics and contribute to variations in the redox conditions of the mantle.
Collapse
Affiliation(s)
- Li Zhang
- Center for High Pressure Science and Technology Advanced Research, Shanghai, China.
| | - Yongjin Chen
- Center for High Pressure Science and Technology Advanced Research, Shanghai, China
| | - Ziqiang Yang
- Center for High Pressure Science and Technology Advanced Research, Shanghai, China
| | - Lu Liu
- Center for High Pressure Science and Technology Advanced Research, Shanghai, China
| | - Yanping Yang
- Center for High Pressure Science and Technology Advanced Research, Shanghai, China
| | | | - Junyue Wang
- Center for High Pressure Science and Technology Advanced Research, Shanghai, China
| | - Ho-Kwang Mao
- Shanghai Key Laboratory MFree, Institute for Shanghai Advanced Research in Physical Sciences, Shanghai, China
| |
Collapse
|
2
|
Tang R, Liu J, Kim DY, Mao HK, Hu Q, Yang B, Li Y, Pickard CJ, Needs RJ, He Y, Liu H, Prakapenka VB, Meng Y, Yan J. Chemistry and P-V-T equation of state of FeO 2H x at the base of Earth's lower mantle and their geophysical implications. Sci Bull (Beijing) 2021; 66:1954-1958. [PMID: 36654164 DOI: 10.1016/j.scib.2021.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 02/03/2023]
Affiliation(s)
- Ruilian Tang
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China; School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China.
| | - Jin Liu
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China
| | - Duck Young Kim
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China
| | - Ho-Kwang Mao
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China.
| | - Qingyang Hu
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China
| | - Bin Yang
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China
| | - Yan Li
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
| | - Chris J Pickard
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK; Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Richard J Needs
- Theory of Condensed Matter Group, Cavendish Laboratory, Cambridge CB3 0HE, UK
| | - Yu He
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China; Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Haozhe Liu
- Center for High Pressure Science and Technology Advanced Research, Changchun 130012, China
| | - Vitali B Prakapenka
- Center for Advanced Radiation Sources, University of Chicago, Chicago IL 60439, USA
| | - Yue Meng
- X-ray Science Division, Argonne National Laboratory, Argonne IL 60439, USA
| | - Jinyuan Yan
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720, USA
| |
Collapse
|
3
|
Okuda Y, Ohta K, Nishihara Y, Hirao N, Wakamatsu T, Suehiro S, Kawaguchi SI, Ohishi Y. Low-spin ferric iron in primordial bridgmanite crystallized from a deep magma ocean. Sci Rep 2021; 11:19471. [PMID: 34593901 PMCID: PMC8484549 DOI: 10.1038/s41598-021-98991-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/15/2021] [Indexed: 02/08/2023] Open
Abstract
The crystallization of the magma ocean resulted in the present layered structure of the Earth's mantle. An open question is the electronic spin state of iron in bridgmanite (the most abundant mineral on Earth) crystallized from a deep magma ocean, which has been neglected in the crystallization history of the entire magma ocean. Here, we performed energy-domain synchrotron Mössbauer spectroscopy measurements on two bridgmanite samples synthesized at different pressures using the same starting material (Mg0.78Fe0.13Al0.11Si0.94O3). The obtained Mössbauer spectra showed no evidence of low-spin ferric iron (Fe3+) from the bridgmanite sample synthesized at relatively low pressure of 25 gigapascals, while that directly synthesized at a higher pressure of 80 gigapascals contained a relatively large amount. This difference ought to derive from the large kinetic barrier of Fe3+ rearranging from pseudo-dodecahedral to octahedral sites with the high-spin to low-spin transition in experiments. Our results indicate a certain amount of low-spin Fe3+ in the lower mantle bridgmanite crystallized from an ancient magma ocean. We therefore conclude that primordial bridgmanite with low-spin Fe3+ dominated the deeper part of an ancient lower mantle, which would contribute to lower mantle heterogeneity preservation and call for modification of the terrestrial mantle thermal evolution scenarios.
Collapse
Affiliation(s)
- Yoshiyuki Okuda
- grid.32197.3e0000 0001 2179 2105Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, 152-8550 Japan ,grid.26999.3d0000 0001 2151 536XPresent Address: Department of Earth and Planetary Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033 Japan
| | - Kenji Ohta
- grid.32197.3e0000 0001 2179 2105Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, 152-8550 Japan
| | - Yu Nishihara
- grid.255464.40000 0001 1011 3808Geodynamics Research Center, Ehime University, Ehime, 790-8577 Japan
| | - Naohisa Hirao
- grid.410592.b0000 0001 2170 091XJapan Synchrotron Radiation Research Institute, Hyogo, 679-5198 Japan
| | - Tatsuya Wakamatsu
- grid.32197.3e0000 0001 2179 2105Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, 152-8550 Japan
| | - Sho Suehiro
- grid.32197.3e0000 0001 2179 2105Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, 152-8550 Japan
| | - Saori I. Kawaguchi
- grid.410592.b0000 0001 2170 091XJapan Synchrotron Radiation Research Institute, Hyogo, 679-5198 Japan
| | - Yasuo Ohishi
- grid.410592.b0000 0001 2170 091XJapan Synchrotron Radiation Research Institute, Hyogo, 679-5198 Japan
| |
Collapse
|
4
|
Wang W, Liu J, Zhu F, Li M, Dorfman SM, Li J, Wu Z. Formation of large low shear velocity provinces through the decomposition of oxidized mantle. Nat Commun 2021; 12:1911. [PMID: 33771990 PMCID: PMC7997914 DOI: 10.1038/s41467-021-22185-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 02/26/2021] [Indexed: 02/01/2023] Open
Abstract
Large Low Shear Velocity Provinces (LLSVPs) in the lowermost mantle are key to understanding the chemical composition and thermal structure of the deep Earth, but their origins have long been debated. Bridgmanite, the most abundant lower-mantle mineral, can incorporate extensive amounts of iron (Fe) with effects on various geophysical properties. Here our high-pressure experiments and ab initio calculations reveal that a ferric-iron-rich bridgmanite coexists with an Fe-poor bridgmanite in the 90 mol% MgSiO3-10 mol% Fe2O3 system, rather than forming a homogeneous single phase. The Fe3+-rich bridgmanite has substantially lower velocities and a higher VP/VS ratio than MgSiO3 bridgmanite under lowermost-mantle conditions. Our modeling shows that the enrichment of Fe3+-rich bridgmanite in a pyrolitic composition can explain the observed features of the LLSVPs. The presence of Fe3+-rich materials within LLSVPs may have profound effects on the deep reservoirs of redox-sensitive elements and their isotopes.
Collapse
Affiliation(s)
- Wenzhong Wang
- grid.59053.3a0000000121679639Laboratory of Seismology and Physics of Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China ,grid.83440.3b0000000121901201Department of Earth Sciences, University College London, London, UK
| | - Jiachao Liu
- grid.17088.360000 0001 2150 1785Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI USA
| | - Feng Zhu
- grid.214458.e0000000086837370Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA
| | - Mingming Li
- grid.215654.10000 0001 2151 2636School of Earth and Space Exploration, Arizona State University, Tempe, AZ USA
| | - Susannah M. Dorfman
- grid.17088.360000 0001 2150 1785Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI USA
| | - Jie Li
- grid.214458.e0000000086837370Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA
| | - Zhongqing Wu
- grid.59053.3a0000000121679639Laboratory of Seismology and Physics of Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China ,grid.59053.3a0000000121679639National Geophysical Observatory at Mengcheng, University of Science and Technology of China, Hefei, China ,grid.59053.3a0000000121679639CAS Center for Excellence in Comparative Planetology, USTC, Hefei, Anhui China
| |
Collapse
|
5
|
Chandler B, Bernier J, Diamond M, Kunz M, Wenk HR. Exploring microstructures in lower mantle mineral assemblages with synchrotron x-rays. SCIENCE ADVANCES 2021; 7:7/1/eabd3614. [PMID: 33523845 PMCID: PMC7775751 DOI: 10.1126/sciadv.abd3614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/11/2020] [Indexed: 06/12/2023]
Abstract
Understanding dynamics across phase transformations and the spatial distribution of minerals in the lower mantle is crucial for a comprehensive model of the evolution of the Earth's interior. Using the multigrain crystallography technique (MGC) with synchrotron x-rays at pressures of 30 GPa in a laser-heated diamond anvil cell to study the formation of bridgmanite [(Mg,Fe)SiO3] and ferropericlase [(Mg,Fe)O], we report an interconnected network of a smaller grained ferropericlase, a configuration that has been implicated in slab stagnation and plume deflection in the upper part of the lower mantle. Furthermore, we isolated individual crystal orientations with grain-scale resolution, provide estimates on stress evolutions on the grain scale, and report {110} twinning in an iron-depleted bridgmanite, a mechanism that appears to aid stress relaxation during grain growth and likely contributes to the lack of any appreciable seismic anisotropy in the upper portion of the lower mantle.
Collapse
Affiliation(s)
- Brian Chandler
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA.
- The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Joel Bernier
- Engineering Technologies Division, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Matthew Diamond
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
| | - Martin Kunz
- The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Hans-Rudolf Wenk
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
| |
Collapse
|
6
|
Abstract
δ -AlOOH has been shown to be stable at the pressure–temperature conditions of the lower mantle. However, its stability remains uncertain at the conditions expected for the lowermost mantle where temperature is expected to rise quickly with increasing depth. Our laser-heated diamond-anvil cell experiments show that δ -AlOOH undergoes dehydration at ∼2000 K above 90 GPa. This dehydration temperature is lower than geotherm temperatures expected at the bottom ∼700 km of the mantle and suggests that δ -AlOOH in warm slabs would dehydrate in this region. Our experiments also show that the released H 2 O from dehydration of δ -AlOOH can react with metallic iron, forming iron oxide, iron hydroxide, and possibly iron hydride. Our observations suggest that H 2 O from the dehydration of subducting slabs, if it occurs, could alter the chemical composition of the surrounding mantle and core regions.
Collapse
|
7
|
Armstrong K, Frost DJ, McCammon CA, Rubie DC, Boffa Ballaran T. Deep magma ocean formation set the oxidation state of Earth's mantle. Science 2020; 365:903-906. [PMID: 31467218 DOI: 10.1126/science.aax8376] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/02/2019] [Indexed: 11/02/2022]
Abstract
The composition of Earth's atmosphere depends on the redox state of the mantle, which became more oxidizing at some stage after Earth's core started to form. Through high-pressure experiments, we found that Fe2+ in a deep magma ocean would disproportionate to Fe3+ plus metallic iron at high pressures. The separation of this metallic iron to the core raised the oxidation state of the upper mantle, changing the chemistry of degassing volatiles that formed the atmosphere to more oxidized species. Additionally, the resulting gradient in redox state of the magma ocean allowed dissolved CO2 from the atmosphere to precipitate as diamond at depth. This explains Earth's carbon-rich interior and suggests that redox evolution during accretion was an important variable in determining the composition of the terrestrial atmosphere.
Collapse
Affiliation(s)
| | - Daniel J Frost
- Bayerisches Geoinstitut, University of Bayreuth, D-95447 Bayreuth, Germany.
| | | | - David C Rubie
- Bayerisches Geoinstitut, University of Bayreuth, D-95447 Bayreuth, Germany
| | | |
Collapse
|
8
|
Bindi L, Shim SH, Sharp TG, Xie X. Evidence for the charge disproportionation of iron in extraterrestrial bridgmanite. SCIENCE ADVANCES 2020; 6:eaay7893. [PMID: 31950086 PMCID: PMC6954055 DOI: 10.1126/sciadv.aay7893] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
Bridgmanite, MgSiO3 with perovskite structure, is considered the most abundant mineral on Earth. On the lower mantle, it contains Fe and Al that strongly influence its behavior. Experimentalists have debated whether iron may exist in a mixed valence state, coexistence of Fe2+ and Fe3+ in bridgmanite, through charge disproportionation. Here, we report the discovery of Fe-rich aluminous bridgmanite coexisting with metallic iron in a shock vein of the Suizhou meteorite. This is the first direct evidence in nature of the Fe disproportionation reaction, which so far has only been observed in some high-pressure experiments. Furthermore, our discovery supports the idea that the disproportionation reaction would have played a key role in redox processes and the evolution of Earth.
Collapse
Affiliation(s)
- Luca Bindi
- Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira 4, I-50121 Firenze, Italy
| | - Sang-Heon Shim
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
| | - Thomas G. Sharp
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
| | - Xiande Xie
- Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| |
Collapse
|
9
|
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.
Collapse
|
10
|
|
11
|
Valence and spin states of iron are invisible in Earth's lower mantle. Nat Commun 2018; 9:1284. [PMID: 29599446 PMCID: PMC5876394 DOI: 10.1038/s41467-018-03671-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 03/05/2018] [Indexed: 11/09/2022] Open
Abstract
Heterogeneity in Earth's mantle is a record of chemical and dynamic processes over Earth's history. The geophysical signatures of heterogeneity can only be interpreted with quantitative constraints on effects of major elements such as iron on physical properties including density, compressibility, and electrical conductivity. However, deconvolution of the effects of multiple valence and spin states of iron in bridgmanite (Bdg), the most abundant mineral in the lower mantle, has been challenging. Here we show through a study of a ferric-iron-only (Mg0.46Fe3+0.53)(Si0.49Fe3+0.51)O3 Bdg that Fe3+ in the octahedral site undergoes a spin transition between 43 and 53 GPa at 300 K. The resolved effects of the spin transition on density, bulk sound velocity, and electrical conductivity are smaller than previous estimations, consistent with the smooth depth profiles from geophysical observations. For likely mantle compositions, the valence state of iron has minor effects on density and sound velocities relative to major cation composition.
Collapse
|
12
|
Deng J, Lee KKM. Viscosity jump in the lower mantle inferred from melting curves of ferropericlase. Nat Commun 2017; 8:1997. [PMID: 29222478 PMCID: PMC5722891 DOI: 10.1038/s41467-017-02263-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/16/2017] [Indexed: 11/09/2022] Open
Abstract
Convection provides the mechanism behind plate tectonics, which allows oceanic lithosphere to be subducted into the mantle as "slabs" and new rock to be generated by volcanism. Stagnation of subducting slabs and deflection of rising plumes in Earth's shallow lower mantle have been suggested to result from a viscosity increase at those depths. However, the mechanism for this increase remains elusive. Here, we examine the melting behavior in the MgO-FeO binary system at high pressures using the laser-heated diamond-anvil cell and show that the liquidus and solidus of (Mg x Fe1-x )O ferropericlase (x = ~0.52-0.98), exhibit a local maximum at ~40 GPa, likely caused by the spin transition of iron. We calculate the relative viscosity profiles of ferropericlase using homologous temperature scaling and find that viscosity increases 10-100 times from ~750 km to ~1000-1250 km, with a smaller decrease at deeper depths, pointing to a single mechanism for slab stagnation and plume deflection.
Collapse
Affiliation(s)
- Jie Deng
- Department of Geology and Geophysics, Yale University, New Haven, CT, 06511, USA.
| | - Kanani K M Lee
- Department of Geology and Geophysics, Yale University, New Haven, CT, 06511, USA
| |
Collapse
|
13
|
Affiliation(s)
- Kei Hirose
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Ryosuke Sinmyo
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - John Hernlund
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan
| |
Collapse
|