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Ray S, Garvie LAJ, Rai VK, Wadhwa M. Correlated iron isotopes and silicon contents in aubrite metals reveal structure of their asteroidal parent body. Sci Rep 2021; 11:22552. [PMID: 34799673 PMCID: PMC8605012 DOI: 10.1038/s41598-021-99160-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
Iron isotopes record the physical parameters, such as temperature and redox conditions, during differentiation processes on rocky bodies. Here we report the results of a correlated investigation of iron isotope compositions and silicon contents of silicon-bearing metal grains from several aubritic meteorites. Based on their Fe isotopic and elemental Si compositions and thermal modelling, we show that these aubrite metals equilibrated with silicates at temperatures ranging from ~ 1430 to ~ 1640 K and likely sampled different depths within their asteroidal parent body. The highest temperature in this range corresponds to their equilibration at a minimum depth of up to ~ 35 km from the surface of the aubrite parent body, followed by brecciation and excavation by impacts within the first ~ 4 Myr of Solar System history.
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Affiliation(s)
- Soumya Ray
- School of Earth and Space Exploration, Arizona State University, Tempe, 85287, USA.
| | - Laurence A J Garvie
- School of Earth and Space Exploration, Arizona State University, Tempe, 85287, USA.,Center for Meteorite Studies, Arizona State University, Tempe, 85287, USA
| | - Vinai K Rai
- School of Earth and Space Exploration, Arizona State University, Tempe, 85287, USA
| | - Meenakshi Wadhwa
- School of Earth and Space Exploration, Arizona State University, Tempe, 85287, USA
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Iron Isotope Compositions of Coexisting Sulfide and Silicate Minerals in Sudbury-Type Ores from the Jinchuan Ni-Cu Sulfide Deposit: A Perspective on Possible Core-Mantle Iron Isotope Fractionation. MINERALS 2021. [DOI: 10.3390/min11050464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many studies have shown that the average iron (Fe) isotope compositions of mantle-derived rocks, mantle peridotite and model mantle are close to those of chondrites. Therefore, it is considered that chondrite values represent the bulk Earth Fe isotope composition. However, this is a brave assumption because nearly 90% of Fe of the Earth is in the core, where its Fe isotope composition is unknown, but it is required to construct bulk Earth Fe isotope composition. We approach the problem by assuming that the Earth’s core separation can be approximated in terms of the Sudbury-type Ni-Cu sulfide mineralization, where sulfide-saturated mafic magmas segregate into immiscible sulfide liquid and silicate liquid. Their density/buoyancy controlled stratification and solidification produced net-textured ores above massive ores and below disseminated ores. The coexisting sulfide minerals (pyrrhotite (Po) > pentlandite (Pn) > chalcopyrite (Cp)) and silicate minerals (olivine (Ol) > orthopyroxene (Opx) > clinopyroxene (Cpx)) are expected to hold messages on Fe isotope fractionation between the two liquids before their solidification. We studied the net-textured ores of the Sudbury-type Jinchuan Ni-Cu sulfide deposit. The sulfide minerals show varying δ56Fe values (−1.37–−0.74‰ (Po) < 0.09–0.56‰ (Cp) < 0.53–1.05‰ (Pn)), but silicate minerals (Ol, Opx, and Cpx) have δ56Fe values close to chondrites (δ56Fe = −0.01 ± 0.01‰). The heavy δ56Fe value (0.52–0.60‰) of serpentines may reflect Fe isotopes exchange with the coexisting pyrrhotite with light δ56Fe. We obtained an equilibrium fractionation factor of Δ56Fesilicate-sulfide ≈ 0.51‰ between reconstructed silicate liquid (δ56Fe ≈ 0.21‰) and sulfide liquid (δ56Fe ≈ −0.30‰), or Δ56Fesilicate-sulfide ≈ 0.36‰ between the weighted mean bulk-silicate minerals (δ56Fe[0.70ol,0.25opx,0.05cpx] = 0.06‰) with weighted mean bulk-sulfide minerals (δ56Fe ≈ −0.30‰). Our study indicates that significant Fe isotope fractionation does take place between silicate and sulfide liquids during the Sudbury-type sulfide mineralization. We hypothesize that significant iron isotope fractionation must have taken place during core–mantle segregation, and the bulk Earth may have lighter Fe isotope composition than chondrites although Fe isotope analysis on experimental sulfide-silicate liquids produced under the varying mantle depth conditions is needed to test our results. We advocate the importance of further research on the subject. Given the close Fe-Ni association in the magmatic mineralization and the majority of the Earth’s Ni is also in the core, we infer that Ni isotope fractionation must also have taken place during the core separation that needs attention.
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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.
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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
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Smith EM, Ni P, Shirey SB, Richardson SH, Wang W, Shahar A. Heavy iron in large gem diamonds traces deep subduction of serpentinized ocean floor. SCIENCE ADVANCES 2021; 7:7/14/eabe9773. [PMID: 33789901 PMCID: PMC8011960 DOI: 10.1126/sciadv.abe9773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 02/11/2021] [Indexed: 06/12/2023]
Abstract
Subducting tectonic plates carry water and other surficial components into Earth's interior. Previous studies suggest that serpentinized peridotite is a key part of deep recycling, but this geochemical pathway has not been directly traced. Here, we report Fe-Ni-rich metallic inclusions in sublithospheric diamonds from a depth of 360 to 750 km with isotopically heavy iron (δ56Fe = 0.79 to 0.90‰) and unradiogenic osmium (187Os/188Os = 0.111). These iron values lie outside the range of known mantle compositions or expected reaction products at depth. This signature represents subducted iron from magnetite and/or Fe-Ni alloys precipitated during serpentinization of oceanic peridotite, a lithology known to carry unradiogenic osmium inherited from prior convection and melt depletion. These diamond-hosted inclusions trace serpentinite subduction into the mantle transition zone. We propose that iron-rich phases from serpentinite contribute a labile heavy iron component to the heterogeneous convecting mantle eventually sampled by oceanic basalts.
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Affiliation(s)
- Evan M Smith
- Gemological Institute of America, New York, NY 10036, USA.
| | - Peng Ni
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA.
| | - Steven B Shirey
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
| | - Stephen H Richardson
- Department of Geological Sciences, University of Cape Town, Rondebosch 7701, South Africa
| | - Wuyi Wang
- Gemological Institute of America, New York, NY 10036, USA
| | - Anat Shahar
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
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Ni P, Chabot NL, Ryan CJ, Shahar A. Heavy iron isotope composition of iron meteorites explained by core crystallization. NATURE GEOSCIENCE 2020; 13:611-615. [PMID: 32952605 PMCID: PMC7500481 DOI: 10.1038/s41561-020-0617-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Similar to Earth, many large planetesimals in the Solar System experienced planetary-scale processes such as accretion, melting, and differentiation. As their cores cooled and solidified, significant chemical fractionation occurred due to solid metal-liquid metal fractionation. Iron meteorites -- core remnants of these ancient planetesimals -- record a history of this process. Recent Fe isotope analyses of iron meteorites found δ57/54Fe to be heavier than chondritic by approximately 0.1 to 0.2 ‰ for most meteorites, indicating that a common parent body process was responsible. However, the mechanism for this fractionation remains poorly understood. Here we experimentally show that the Fe isotopic composition of iron meteorites can be explained solely by core crystallization. In our experiments of core crystallization at 1300 °C, we find that solid metal becomes enriched in δ57/54Fe by 0.13 ‰ relative to liquid metal. Fractional crystallization modelling of the IIIAB iron meteorite parent body shows that observed Ir, Au and Fe isotopic compositions can be simultaneously reproduced during core crystallization. The model implies the formation of complementary S-rich components of the iron meteorite parental cores that remain unsampled by meteorite records and may be the missing reservoir of isotopically-light Fe. The lack of sulfide meteorites and previous trace element modeling predicting significant unsampled volumes of iron meteorite parent cores support our findings.
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Affiliation(s)
- Peng Ni
- Earth and Planets Laboratory, Carnegie Institution for
Science, Washington, DC 20015, USA
| | - Nancy L. Chabot
- Johns Hopkins University Applied Physics Laboratory,
Laurel, MD 20723, USA
| | - Caillin J. Ryan
- Johns Hopkins University Applied Physics Laboratory,
Laurel, MD 20723, USA
| | - Anat Shahar
- Earth and Planets Laboratory, Carnegie Institution for
Science, Washington, DC 20015, USA
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Chang CHT, Jiang PC, Chow YT, Hsiao HL, Su WB, Tsay JS. Enhancing silicide formation in Ni/Si(111) by Ag-Si particles at the interface. Sci Rep 2019; 9:8835. [PMID: 31222031 PMCID: PMC6586651 DOI: 10.1038/s41598-019-45104-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 05/31/2019] [Indexed: 12/03/2022] Open
Abstract
Compound formation at a metal/semiconductor interface plays crucial roles in the properties of many material systems. Applications of Ni silicides span numerous areas and have the potential to be used as new functionalities. However, the magnetic properties of ultrathin Ni layers on silicon surfaces and related chemical compositions at the interface are not fully understood and the influence of Ag additives on the reactivity of Ni/Si(111) remain unclear. We report herein on the fact that the dominant species produced at the interface is NiSi, which is produced by the spontaneous formation of strong bonds between Ni and Si atoms. Assuming that a Ni layer is formed over a NiSi layer with the total coverage as a constraint, we established a chemical shift-related concentration model that, in effect, represents a practical method for determining the amount of ultrathin Ni silicides that are produced at the buried interface. The formation of Ag-Si particles provide a viable strategy for enhancing silicide formation via a specific interaction transfer mechanism, even at room temperature. The mechanism is related to differences in the enthalpies of formation ΔHAg-Si, ΔHNi-Ag, and ΔHNi-Si, for these phases and provides insights into strategies for producing ultrathin silicides at a buried interface.
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Affiliation(s)
- Cheng-Hsun-Tony Chang
- Department of Physics, National Taiwan Normal University, Taipei, 116, Taiwan
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
- Department of Electronic Engineering, Minghsin University of Science and Technology, Hsinchu, 30401, Taiwan
| | - Pei-Cheng Jiang
- Department of Physics, National Taiwan Normal University, Taipei, 116, Taiwan
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Yu-Ting Chow
- Department of Physics, National Taiwan Normal University, Taipei, 116, Taiwan
| | - Hsi-Lien Hsiao
- Department of Physics, Tunghai University, Taichung, 407, Taiwan
| | - Wei-Bin Su
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Jyh-Shen Tsay
- Department of Physics, National Taiwan Normal University, Taipei, 116, Taiwan.
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Dauphas N, Hu MY, Baker EM, Hu J, Tissot FLH, Alp EE, Roskosz M, Zhao J, Bi W, Liu J, Lin JF, Nie NX, Heard A. SciPhon: a data analysis software for nuclear resonant inelastic X-ray scattering with applications to Fe, Kr, Sn, Eu and Dy. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:1581-1599. [PMID: 30179200 PMCID: PMC6140397 DOI: 10.1107/s1600577518009487] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/02/2018] [Indexed: 06/01/2023]
Abstract
The synchrotron radiation technique of nuclear resonant inelastic X-ray scattering (NRIXS), also known as nuclear resonance vibrational spectroscopy or nuclear inelastic scattering, provides a wealth of information on the vibrational properties of solids. It has found applications in studies of lattice dynamics and elasticity, superconductivity, heme biochemistry, seismology, isotope geochemistry and many other fields. It involves probing the vibrational modes of solids by using the nuclear resonance of Mössbauer isotopes such as 57Fe, 83Kr, 119Sn, 151Eu and 161Dy. After data reduction, it provides the partial phonon density of states of the Mössbauer isotope that is investigated, as well as many other derived quantities such as the mean force constant of the chemical bonds and the Debye velocity. The data reduction is, however, not straightforward and involves removal of the elastic peak, normalization and Fourier-Log transformation. Furthermore, some of the quantities derived are highly sensitive to details in the baseline correction. A software package and several novel procedures to streamline and hopefully improve the reduction of the NRIXS data generated at sector 3ID of the Advanced Photon Source have been developed. The graphical user interface software is named SciPhon and runs as a Mathematica package. It is easily portable to other platforms and can be easily adapted for reducing data generated at other beamlines. Several tests and comparisons are presented that demonstrate the usefulness of this software, whose results have already been used in several publications. Here, the SciPhon software is used to reduce Kr, Sn, Eu and Dy NRIXS data, and potential implications for interpreting natural isotopic variations in those systems are discussed.
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Affiliation(s)
- Nicolas Dauphas
- Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60615, USA
| | - Michael Y. Hu
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - Erik M. Baker
- Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60615, USA
- Department of Earth and Planetary Sciences, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Justin Hu
- Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60615, USA
| | - Francois L. H. Tissot
- Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60615, USA
| | - E. Ercan Alp
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - Mathieu Roskosz
- IMPMC-UMR CNRS 7590, Sorbonne Universités, UPMC, IRD, MNHN, Muséum National d’Histoire Naturelle, 61 Rue Buffon, 75005 Paris, France
| | - Jiyong Zhao
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - Wenli Bi
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - Jin Liu
- Department of Geological Sciences, Stanford University, Stanford, CA, USA
| | - Jung-Fu Lin
- Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Nicole X. Nie
- Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60615, USA
| | - Andrew Heard
- Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60615, USA
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Hydrogen-bearing iron peroxide and the origin of ultralow-velocity zones. Nature 2017; 551:494-497. [DOI: 10.1038/nature24461] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/27/2017] [Indexed: 11/08/2022]
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