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Li Y. The origin and evolution of Earth's nitrogen. Natl Sci Rev 2024; 11:nwae201. [PMID: 38966072 PMCID: PMC11223583 DOI: 10.1093/nsr/nwae201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 05/23/2024] [Accepted: 06/09/2024] [Indexed: 07/06/2024] Open
Abstract
Nitrogen is a vital element for life on Earth. Its cycling between the surface (atmosphere + crust) and the mantle has a profound influence on the atmosphere and climate. However, our understanding of the origin and evolution of Earth's nitrogen is still incomplete. This review presents an overview of the current understanding of Earth's nitrogen budget and the isotope composition of different reservoirs, laboratory constraints on deep nitrogen geochemistry, and our understanding of the origin of Earth's nitrogen and the deep nitrogen cycle through plate subduction and volcanism. The Earth may have acquired its nitrogen heterogeneously during the main accretion phase, initially from reduced, enstatite-chondrite-like impactors, and subsequently from increasingly oxidized impactors and minimal CI-chondrite-like materials. Like Earth's surface, the mantle and core are also significant nitrogen reservoirs. The nitrogen abundance and isotope composition of these three reservoirs may have been fundamentally established during the main accretion phase and have been insignificantly modified afterwards by the deep nitrogen cycle, although there is a net nitrogen ingassing into Earth's mantle in modern subduction zones. However, it is estimated that the early atmosphere of Earth may have contained ∼1.4 times the present-day atmospheric nitrogen (PAN), with ∼0.4 PAN being sequestered into the crust via biotic nitrogen fixation. In order to gain a better understanding of the origin and evolution of Earth's nitrogen, directions for future research are suggested.
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Affiliation(s)
- Yuan Li
- State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
- Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth 95440, Germany
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2
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Wang W, Walter MJ, Brodholt JP, Huang S. Early planetesimal differentiation and late accretion shaped Earth's nitrogen budget. Nat Commun 2024; 15:4169. [PMID: 38755135 PMCID: PMC11099130 DOI: 10.1038/s41467-024-48500-0] [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: 01/23/2024] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
The relative roles of protoplanetary differentiation versus late accretion in establishing Earth's life-essential volatile element inventory are being hotly debated. To address this issue, we employ first-principles calculations to investigate nitrogen (N) isotope fractionation during Earth's accretion and differentiation. We find that segregation of an iron core would enrich heavy N isotopes in the residual silicate, while evaporation within a H2-dominated nebular gas produces an enrichment of light N isotope in the planetesimals. The combined effect of early planetesimal evaporation followed by core formation enriches the bulk silicate Earth in light N isotopes. If Earth is comprised primarily of enstatite-chondrite-like material, as indicated by other isotope systems, then late accretion of carbonaceous-chondrite-like material must contribute ~ 30-100% of the N budget in present-day bulk silicate Earth. However, mass balance using N isotope constraints shows that the late veneer contributes only a limited amount of other volatile elements (e.g., H, S, and C) to Earth.
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Affiliation(s)
- Wenzhong Wang
- Deep Space Exploration Lab/School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, Anhui, China.
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, 20015, USA.
- Department of Earth Sciences, University College London, London, WC1E 6BT, UK.
| | - Michael J Walter
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, 20015, USA
| | - John P Brodholt
- Department of Earth Sciences, University College London, London, WC1E 6BT, UK
- The Centre of Planetary Habitability, University of Oslo, Oslo, Norway
| | - Shichun Huang
- Department of Earth, Environmenral, & Planetary Sciences, University of Tennessee at Knoxville, Knoxville, TN, USA
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3
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Wang W, Walter MJ, Brodholt JP, Huang S, Petaev MI. Chalcogen isotopes reveal limited volatile contribution from late veneer to Earth. SCIENCE ADVANCES 2023; 9:eadh0670. [PMID: 38055829 DOI: 10.1126/sciadv.adh0670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 11/07/2023] [Indexed: 12/08/2023]
Abstract
The origin of Earth's volatile elements is highly debated. Comparing the chalcogen isotope ratios in the bulk silicate Earth (BSE) to those of its possible building blocks, chondritic meteorites, allows constraints on the origin of Earth's volatiles; however, these comparisons are complicated by potential isotopic fractionation during protoplanetary differentiation, which largely remains poorly understood. Using first-principles calculations, we find that core-mantle differentiation does not notably fractionate selenium and tellurium isotopes, while equilibrium evaporation from early planetesimals would enrich selenium and tellurium in heavy isotopes in the BSE. The sulfur, selenium, and tellurium isotopic signatures of the BSE reveal that protoplanetary differentiation plays a key role in establishing most of Earth's volatile elements, and a late veneer does not substantially contribute to the BSE's volatile inventory.
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Affiliation(s)
- Wenzhong Wang
- Deep Space Exploration Lab/School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, Anhui 230026, China
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
- Department of Earth Sciences, University College London, London WC1E 6BT, UK
| | - Michael J Walter
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
| | - John P Brodholt
- Department of Earth Sciences, University College London, London WC1E 6BT, UK
- Centre of Planetary Habitability, University of Oslo, Oslo, Norway
| | - Shichun Huang
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996, USA
| | - Michail I Petaev
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
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4
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Mrnjavac N, Wimmer JLE, Brabender M, Schwander L, Martin WF. The Moon-Forming Impact and the Autotrophic Origin of Life. Chempluschem 2023; 88:e202300270. [PMID: 37812146 PMCID: PMC7615287 DOI: 10.1002/cplu.202300270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/10/2023]
Abstract
The Moon-forming impact vaporized part of Earth's mantle, and turned the rest into a magma ocean, from which carbon dioxide degassed into the atmosphere, where it stayed until water rained out to form the oceans. The rain dissolved CO2 and made it available to react with transition metal catalysts in the Earth's crust so as to ultimately generate the organic compounds that form the backbone of microbial metabolism. The Moon-forming impact was key in building a planet with the capacity to generate life in that it converted carbon on Earth into a homogeneous and accessible substrate for organic synthesis. Today all ecosystems, without exception, depend upon primary producers, organisms that fix CO2 . According to theories of autotrophic origin, it has always been that way, because autotrophic theories posit that the first forms of life generated all the molecules needed to build a cell from CO2 , forging a direct line of continuity between Earth's initial CO2 -rich atmosphere and the first microorganisms. By modern accounts these were chemolithoautotrophic archaea and bacteria that initially colonized the crust and still inhabit that environment today.
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Affiliation(s)
- Natalia Mrnjavac
- Department of Biology Institute for Molecular Evolution Heinrich Heine University Duesseldorf Universitaetsstr. 1, 40225 Düsseldorf (Germany)
| | - Jessica L. E. Wimmer
- Department of Biology Institute for Molecular Evolution Heinrich Heine University Duesseldorf Universitaetsstr. 1, 40225 Düsseldorf (Germany)
| | - Max Brabender
- Department of Biology Institute for Molecular Evolution Heinrich Heine University Duesseldorf Universitaetsstr. 1, 40225 Düsseldorf (Germany)
| | - Loraine Schwander
- Department of Biology Institute for Molecular Evolution Heinrich Heine University Duesseldorf Universitaetsstr. 1, 40225 Düsseldorf (Germany)
| | - William F. Martin
- Department of Biology Institute for Molecular Evolution Heinrich Heine University Duesseldorf Universitaetsstr. 1, 40225 Düsseldorf (Germany)
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5
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Schwander L, Brabender M, Mrnjavac N, Wimmer JLE, Preiner M, Martin WF. Serpentinization as the source of energy, electrons, organics, catalysts, nutrients and pH gradients for the origin of LUCA and life. Front Microbiol 2023; 14:1257597. [PMID: 37854333 PMCID: PMC10581274 DOI: 10.3389/fmicb.2023.1257597] [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: 07/12/2023] [Accepted: 09/04/2023] [Indexed: 10/20/2023] Open
Abstract
Serpentinization in hydrothermal vents is central to some autotrophic theories for the origin of life because it generates compartments, reductants, catalysts and gradients. During the process of serpentinization, water circulates through hydrothermal systems in the crust where it oxidizes Fe (II) in ultramafic minerals to generate Fe (III) minerals and H2. Molecular hydrogen can, in turn, serve as a freely diffusible source of electrons for the reduction of CO2 to organic compounds, provided that suitable catalysts are present. Using catalysts that are naturally synthesized in hydrothermal vents during serpentinization H2 reduces CO2 to formate, acetate, pyruvate, and methane. These compounds represent the backbone of microbial carbon and energy metabolism in acetogens and methanogens, strictly anaerobic chemolithoautotrophs that use the acetyl-CoA pathway of CO2 fixation and that inhabit serpentinizing environments today. Serpentinization generates reduced carbon, nitrogen and - as newer findings suggest - reduced phosphorous compounds that were likely conducive to the origins process. In addition, it gives rise to inorganic microcompartments and proton gradients of the right polarity and of sufficient magnitude to support chemiosmotic ATP synthesis by the rotor-stator ATP synthase. This would help to explain why the principle of chemiosmotic energy harnessing is more conserved (older) than the machinery to generate ion gradients via pumping coupled to exergonic chemical reactions, which in the case of acetogens and methanogens involve H2-dependent CO2 reduction. Serpentinizing systems exist in terrestrial and deep ocean environments. On the early Earth they were probably more abundant than today. There is evidence that serpentinization once occurred on Mars and is likely still occurring on Saturn's icy moon Enceladus, providing a perspective on serpentinization as a source of reductants, catalysts and chemical disequilibrium for life on other worlds.
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Affiliation(s)
- Loraine Schwander
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Max Brabender
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Natalia Mrnjavac
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Jessica L. E. Wimmer
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Martina Preiner
- Microcosm Earth Center, Max Planck Institute for Terrestrial Microbiology and Philipps-Universität, Marburg, Germany
| | - William F. Martin
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
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6
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Onyett IJ, Schiller M, Makhatadze GV, Deng Z, Johansen A, Bizzarro M. Silicon isotope constraints on terrestrial planet accretion. Nature 2023; 619:539-544. [PMID: 37316662 PMCID: PMC10356600 DOI: 10.1038/s41586-023-06135-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/26/2023] [Indexed: 06/16/2023]
Abstract
Understanding the nature and origin of the precursor material to terrestrial planets is key to deciphering the mechanisms and timescales of planet formation1. Nucleosynthetic variability among rocky Solar System bodies can trace the composition of planetary building blocks2-5. Here we report the nucleosynthetic composition of silicon (μ30Si), the most abundant refractory planet-building element, in primitive and differentiated meteorites to identify terrestrial planet precursors. Inner Solar System differentiated bodies, including Mars, record μ30Si deficits of -11.0 ± 3.2 parts per million to -5.8 ± 3.0 parts per million whereas non-carbonaceous and carbonaceous chondrites show μ30Si excesses from 7.4 ± 4.3 parts per million to 32.8 ± 2.0 parts per million relative to Earth. This establishes that chondritic bodies are not planetary building blocks. Rather, material akin to early-formed differentiated asteroids must represent a major planetary constituent. The μ30Si values of asteroidal bodies correlate with their accretion ages, reflecting progressive admixing of a μ30Si-rich outer Solar System material to an initially μ30Si-poor inner disk. Mars' formation before chondrite parent bodies is necessary to avoid incorporation of μ30Si-rich material. In contrast, Earth's μ30Si composition necessitates admixing of 26 ± 9 per cent of μ30Si-rich outer Solar System material to its precursors. The μ30Si compositions of Mars and proto-Earth are consistent with their rapid formation by collisional growth and pebble accretion less than three million years after Solar System formation. Finally, Earth's nucleosynthetic composition for s-process sensitive (molybdenum and zirconium) and siderophile (nickel) tracers are consistent with pebble accretion when volatility-driven processes during accretion and the Moon-forming impact are carefully evaluated.
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Affiliation(s)
- Isaac J Onyett
- Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark.
| | - Martin Schiller
- Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Georgy V Makhatadze
- Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Zhengbin Deng
- Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Anders Johansen
- Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
- Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Martin Bizzarro
- Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Copenhagen, Denmark
- Institut de Physique du Globe de Paris, Université de Paris Cité, Paris, France
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7
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Newcombe ME, Nielsen SG, Peterson LD, Wang J, Alexander CMO, Sarafian AR, Shimizu K, Nittler LR, Irving AJ. Degassing of early-formed planetesimals restricted water delivery to Earth. Nature 2023; 615:854-857. [PMID: 36922597 DOI: 10.1038/s41586-023-05721-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 01/06/2023] [Indexed: 03/17/2023]
Abstract
The timing of delivery and the types of body that contributed volatiles to the terrestrial planets remain highly debated1,2. For example, it is unknown if differentiated bodies, such as that responsible for the Moon-forming giant impact, could have delivered substantial volatiles3,4 or if smaller, undifferentiated objects were more probable vehicles of water delivery5-7. Here we show that the water contents of minerals in achondrite meteorites (mantles or crusts of differentiated planetesimals) from both the inner and outer portions of the early Solar System are ≤2 μg g-1 H2O. These are among the lowest values ever reported for extraterrestrial minerals. Our results demonstrate that differentiated planetesimals efficiently degassed before or during melting. This finding implies that substantial amounts of water could only have been delivered to Earth by means of unmelted material.
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Affiliation(s)
| | - S G Nielsen
- NIRVANA Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - J Wang
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - C M O'D Alexander
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | | | - K Shimizu
- University of Wisconsin, Madison, WI, USA
| | - L R Nittler
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
- School Of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - A J Irving
- University of Washington, Seattle, WA, USA
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8
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Leong PK, Sekine T, Tam KV, Tam SI, Tang CP. First-Principles Calculations with Six Structures of Alkaline Earth Metal Cyanide A(CN) 2 (A = Be, Mg, Ca, Sr, and Ba): Structural, Electrical, and Phonon Properties. ACS OMEGA 2023; 8:2973-2981. [PMID: 36713722 PMCID: PMC9878677 DOI: 10.1021/acsomega.2c05667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/18/2022] [Indexed: 06/18/2023]
Abstract
This work examines six structures (P4̅3m, P42 nm, R3m, P21/c, R3̅m, and C2/m) of alkaline earth metal cyanide A(CN)2 (A = Be, Mg, Ca, Sr, and Ba) using first-principles calculations. The symmetries of P4̅3m, P42 nm, and R3m reflect a variation of Pn3̅m, previously reported as occurring on Be(CN)2 and Mg(CN)2 in X-ray diffraction studies, while the symmetries of P21/c, R3̅m, and C2/m were selected from the P3̅m1 symmetry found using Mg(OH)2 as the initial structures, with -OH being replaced by -CN. The band structure, density of states, and phonon properties of all A(CN)2 structures were then investigated using density functional theory (DFT), with a generalized gradient approximation (GGA) applied for the exchange and correlation energy values. The simulation results for the phonon spectra indicate that the stable structures are Be(CN)2 (P4̅3m, P42 nm, and C2/m), Mg(CN)2 (P4̅3m, P42 nm, and C2/m), Ca(CN)2 (P21/c), Sr(CN)2 (P21/c and R3̅m), and Ba(CN)2 (R3̅m) at 0 GPa. For the effects of high pressure, Ca(CN)2 and Sr(CN)2 were thus found to be stable as C2/m at pressures above 10 and 3 GPa, respectively, while Ca(CN)2 is as stable as R3̅m above 15 GPa. In the calculated band structures, all of the compounds with the C2/m structure demonstrated good conductivity, while the other structures have a band gap range of 2.83-6.33 eV.
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Affiliation(s)
- Pak Kin Leong
- State
Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Taipa 999078, Macao, China
| | - Toshimori Sekine
- Center
for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Kuan Vai Tam
- School
of Astronomy and Space Science, Nanjing
University, Nanjing 210093, China
| | - Sok I. Tam
- Faculty
of Innovation Engineering, Macau University
of Science and Technology, Taipa 999078, Macao, China
| | - Chi Pui Tang
- State
Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Taipa 999078, Macao, China
- Faculty
of Innovation Engineering, Macau University
of Science and Technology, Taipa 999078, Macao, China
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9
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Broadley MW, Bekaert DV, Piani L, Füri E, Marty B. Origin of life-forming volatile elements in the inner Solar System. Nature 2022; 611:245-255. [DOI: 10.1038/s41586-022-05276-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/25/2022] [Indexed: 11/11/2022]
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10
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Sources of Nitrogen-, Sulfur-, and Phosphorus-Containing Feedstocks for Prebiotic Chemistry in the Planetary Environment. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081268. [PMID: 36013447 PMCID: PMC9410288 DOI: 10.3390/life12081268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/13/2022] [Accepted: 08/17/2022] [Indexed: 11/21/2022]
Abstract
Biochemistry on Earth makes use of the key elements carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (or CHONPS). Chemically accessible molecules containing these key elements would presumably have been necessary for prebiotic chemistry and the origins of life on Earth. For example, feedstock molecules including fixed nitrogen (e.g., ammonia, nitrite, nitrate), accessible forms of phosphorus (e.g., phosphate, phosphite, etc.), and sources of sulfur (e.g., sulfide, sulfite) may have been necessary for the origins of life, given the biochemistry seen in Earth life today. This review describes potential sources of nitrogen-, sulfur-, and phosphorus-containing molecules in the context of planetary environments. For the early Earth, such considerations may be able to aid in the understanding of our own origins. Additionally, as we learn more about potential environments on other planets (for example, with upcoming next-generation telescope observations or new missions to explore other bodies in our Solar System), evaluating potential sources for elements necessary for life (as we know it) can help constrain the potential habitability of these worlds.
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11
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Nitrogen isotope evidence for Earth's heterogeneous accretion of volatiles. Nat Commun 2022; 13:4769. [PMID: 35970934 PMCID: PMC9378614 DOI: 10.1038/s41467-022-32516-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/28/2022] [Indexed: 11/08/2022] Open
Abstract
The origin of major volatiles nitrogen, carbon, hydrogen, and sulfur in planets is critical for understanding planetary accretion, differentiation, and habitability. However, the detailed process for the origin of Earth's major volatiles remains unresolved. Nitrogen shows large isotopic fractionations among geochemical and cosmochemical reservoirs, which could be used to place tight constraints on Earth's volatile accretion process. Here we experimentally determine N-partitioning and -isotopic fractionation between planetary cores and silicate mantles. We show that the core/mantle N-isotopic fractionation factors, ranging from -4‰ to +10‰, are strongly controlled by oxygen fugacity, and the core/mantle N-partitioning is a multi-function of oxygen fugacity, temperature, pressure, and compositions of the core and mantle. After applying N-partitioning and -isotopic fractionation in a planetary accretion and core-mantle differentiation model, we find that the N-budget and -isotopic composition of Earth's crust plus atmosphere, silicate mantle, and the mantle source of oceanic island basalts are best explained by Earth's early accretion of enstatite chondrite-like impactors, followed by accretion of increasingly oxidized impactors and minimal CI chondrite-like materials before and during the Moon-forming giant impact. Such a heterogeneous accretion process can also explain the carbon-hydrogen-sulfur budget in the bulk silicate Earth. The Earth may thus have acquired its major volatile inventory heterogeneously during the main accretion phase.
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12
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Sakuraba H, Kurokawa H, Genda H, Ohta K. Numerous chondritic impactors and oxidized magma ocean set Earth's volatile depletion. Sci Rep 2021; 11:20894. [PMID: 34686749 PMCID: PMC8536732 DOI: 10.1038/s41598-021-99240-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 09/22/2021] [Indexed: 11/22/2022] Open
Abstract
Earth’s surface environment is largely influenced by its budget of major volatile elements: carbon (C), nitrogen (N), and hydrogen (H). Although the volatiles on Earth are thought to have been delivered by chondritic materials, the elemental composition of the bulk silicate Earth (BSE) shows depletion in the order of N, C, and H. Previous studies have concluded that non-chondritic materials are needed for this depletion pattern. Here, we model the evolution of the volatile abundances in the atmosphere, oceans, crust, mantle, and core through the accretion history by considering elemental partitioning and impact erosion. We show that the BSE depletion pattern can be reproduced from continuous accretion of chondritic bodies by the partitioning of C into the core and H storage in the magma ocean in the main accretion stage and atmospheric erosion of N in the late accretion stage. This scenario requires a relatively oxidized magma ocean (\documentclass[12pt]{minimal}
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\begin{document}$$f_{{\mathrm{O}}_2}$$\end{document}fO2 at the iron-wüstite buffer), the dominance of small impactors in the late accretion, and the storage of H and C in oceanic water and carbonate rocks in the late accretion stage, all of which are naturally expected from the formation of an Earth-sized planet in the habitable zone.
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Affiliation(s)
- Haruka Sakuraba
- Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8551, Japan.
| | - Hiroyuki Kurokawa
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Hidenori Genda
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Kenji Ohta
- Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
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Solomatova NV, Caracas R. Genesis of a CO 2-rich and H 2O-depleted atmosphere from Earth's early global magma ocean. SCIENCE ADVANCES 2021; 7:eabj0406. [PMID: 34613783 PMCID: PMC8494444 DOI: 10.1126/sciadv.abj0406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
The magma ocean was a important reservoir for Earth’s primary volatiles. Understanding the volatile fluxes between the early atmosphere and the magma ocean is fundamental for quantifying the volatile budget of our planet. Here we investigate the vaporization of carbon and hydrogen at the boundary between the magma ocean and the thick, hot early atmosphere using first-principles molecular dynamics calculations. We find that carbon is rapidly devolatilized, while hydrogen mostly remains dissolved in the magma during the existence of a thick silicate-bearing atmosphere. In the early stages of the magma ocean, the atmosphere would have contained significantly more carbon than hydrogen, and the high concentrations of carbon dioxide would have prolonged the cooling time of early Earth.
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Affiliation(s)
- Natalia V. Solomatova
- CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Géologie de Lyon LGLTPE UMR5276, Centre Blaise Pascal, 46 allée d’Italie, Lyon 69364, France
| | - Razvan Caracas
- CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Géologie de Lyon LGLTPE UMR5276, Centre Blaise Pascal, 46 allée d’Italie, Lyon 69364, France
- The Center for Earth Evolution and Dynamics (CEED), University of Oslo, Blindern, Oslo, Norway
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14
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Grewal DS, Dasgupta R, Hough T, Farnell A. Rates of protoplanetary accretion and differentiation set nitrogen budget of rocky planets. NATURE GEOSCIENCE 2021; 14:369-376. [PMID: 34163536 PMCID: PMC8216213 DOI: 10.1038/s41561-021-00733-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 03/10/2021] [Indexed: 06/13/2023]
Abstract
The effect of protoplanetary differentiation on the fate of life-essential volatiles like nitrogen and carbon and its subsequent effect on the dynamics of planetary growth is unknown. Because the dissolution of nitrogen in magma oceans depends on its partial pressure and oxygen fugacity, it is an ideal proxy to track volatile re-distribution in protoplanets as a function of their sizes and growth zones. Using high pressure-temperature experiments in graphite-undersaturated conditions, here we show that the siderophile (iron-loving) character of nitrogen is an order of magnitude higher than previous estimates across a wide range of oxygen fugacity. The experimental data combined with metal-silicate-atmosphere fractionation models suggest that asteroid-sized protoplanets, and planetary embryos that grew from them, were nitrogen-depleted. However, protoplanets that grew to planetary embryo-size before undergoing differentiation had nitrogen-rich cores and nitrogen-poor silicate reservoirs. Bulk silicate reservoirs of large Earth-like planets attained nitrogen from the cores of latter type of planetary embryos. Therefore, to satisfy the volatile budgets of Earth-like planets during the main stage of their growth, the timescales of planetary embryo accretion had to be shorter than their differentiation timescales, i.e., Moon- to Mars-sized planetary embryos grew rapidly within ~1-2 Myrs of the Solar System's formation.
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Affiliation(s)
- Damanveer S. Grewal
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
| | - Rajdeep Dasgupta
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
| | - Taylor Hough
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
| | - Alexandra Farnell
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
- St. John’s School, 2401 Claremont Ln, Houston, TX 77019, USA
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15
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Lichtenberg T, Dra Żkowska J, Schönbächler M, Golabek GJ, Hands TO. Bifurcation of planetary building blocks during Solar System formation. Science 2021; 371:365-370. [PMID: 33479146 DOI: 10.1126/science.abb3091] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 12/10/2020] [Indexed: 11/02/2022]
Abstract
Geochemical and astronomical evidence demonstrates that planet formation occurred in two spatially and temporally separated reservoirs. The origin of this dichotomy is unknown. We use numerical models to investigate how the evolution of the solar protoplanetary disk influenced the timing of protoplanet formation and their internal evolution. Migration of the water snow line can generate two distinct bursts of planetesimal formation that sample different source regions. These reservoirs evolve in divergent geophysical modes and develop distinct volatile contents, consistent with constraints from accretion chronology, thermochemistry, and the mass divergence of inner and outer Solar System. Our simulations suggest that the compositional fractionation and isotopic dichotomy of the Solar System was initiated by the interplay between disk dynamics, heterogeneous accretion, and internal evolution of forming protoplanets.
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Affiliation(s)
- Tim Lichtenberg
- Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK.
| | - Joanna Dra Żkowska
- University Observatory, Faculty of Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Maria Schönbächler
- Institute for Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
| | - Gregor J Golabek
- Bayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany
| | - Thomas O Hands
- Institute for Computational Science, University of Zurich, Zurich, Switzerland
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16
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Wang SJ, Wang W, Zhu JM, Wu Z, Liu J, Han G, Teng FZ, Huang S, Wu H, Wang Y, Wu G, Li W. Nickel isotopic evidence for late-stage accretion of Mercury-like differentiated planetary embryos. Nat Commun 2021; 12:294. [PMID: 33436633 PMCID: PMC7803775 DOI: 10.1038/s41467-020-20525-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 11/30/2020] [Indexed: 11/09/2022] Open
Abstract
Earth's habitability is closely tied to its late-stage accretion, during which impactors delivered the majority of life-essential volatiles. However, the nature of these final building blocks remains poorly constrained. Nickel (Ni) can be a useful tracer in characterizing this accretion as most Ni in the bulk silicate Earth (BSE) comes from the late-stage impactors. Here, we apply Ni stable isotope analysis to a large number of meteorites and terrestrial rocks, and find that the BSE has a lighter Ni isotopic composition compared to chondrites. Using first-principles calculations based on density functional theory, we show that core-mantle differentiation cannot produce the observed light Ni isotopic composition of the BSE. Rather, the sub-chondritic Ni isotopic signature was established during Earth's late-stage accretion, probably through the Moon-forming giant impact. We propose that a highly reduced sulfide-rich, Mercury-like body, whose mantle is characterized by light Ni isotopic composition, collided with and merged into the proto-Earth during the Moon-forming giant impact, producing the sub-chondritic Ni isotopic signature of the BSE, while delivering sulfur and probably other volatiles to the Earth.
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Affiliation(s)
- Shui-Jiong Wang
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China.
| | - Wenzhong Wang
- Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China.,Department of Earth Sciences, University College London, London, WC1E 6BT, UK.,CAS Center for Excellence in Comparative Planetology, USTC, Hefei, China
| | - Jian-Ming Zhu
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China
| | - Zhongqing Wu
- Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China.,CAS Center for Excellence in Comparative Planetology, USTC, Hefei, China
| | - Jingao Liu
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China
| | - Guilin Han
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China
| | - Fang-Zhen Teng
- Isotope Laboratory, Department of Earth and Space Science, University of Washington, Seattle, WA, 98195, USA
| | - Shichun Huang
- Department of Geoscience, University of Nevada, Las Vegas, NV, 89154, USA
| | - Hongjie Wu
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China
| | - Yujian Wang
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China
| | - Guangliang Wu
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China
| | - Weihan Li
- State Key Laboratory of Geological Processes and Minerals Resources, China University of Geosciences, Beijing, 100083, China
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17
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Schulze-Makuch D, Heller R, Guinan E. In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World. ASTROBIOLOGY 2020; 20:1394-1404. [PMID: 32955925 PMCID: PMC7757576 DOI: 10.1089/ast.2019.2161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
The fact that Earth is teeming with life makes it appear odd to ask whether there could be other planets in our galaxy that may be even more suitable for life. Neglecting this possible class of "superhabitable" planets, however, could be considered anthropocentric and geocentric biases. Most important from the perspective of an observer searching for extrasolar life is that such a search might be executed most effectively with a focus on superhabitable planets instead of Earth-like planets. We argue that there could be regions of astrophysical parameter space of star-planet systems that could allow for planets to be even better for life than our Earth. We aim to identify those parameters and their optimal ranges, some of which are astrophysically motivated, whereas others are based on the varying habitability of the natural history of our planet. Some of these conditions are far from being observationally testable on planets outside the solar system. Still, we can distill a short list of 24 top contenders among the >4000 exoplanets known today that could be candidates for a superhabitable planet. In fact, we argue that, with regard to the search for extrasolar life, potentially superhabitable planets may deserve higher priority for follow-up observations than most Earth-like planets.
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Affiliation(s)
- Dirk Schulze-Makuch
- Astrobiology Group, Center for Astronomy and Astrophysics, Technische Universität Berlin, Berlin, Germany
- GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Department of Experimental Limnology, Stechlin, Germany
- School of the Environment, Washington State University, Pullman, Washington, USA
| | - René Heller
- Max Planck Institute for Solar System Research, Göttingen, Germany
- Institute for Astrophysics, Georg-August University, Göttingen, Germany
| | - Edward Guinan
- Department of Astrophysics and Planetary Science, Villanova University, Villanova, Pennsylvania, USA
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18
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Phase Relations in the FeO-Fe3C-Fe3N System at 7.8 GPa and 1350 °C: Implications for Oxidation of Native Iron at 250 km. MINERALS 2020. [DOI: 10.3390/min10110984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidation of native iron in the mantle at a depth about 250 km and its influence on the stability of main carbon and nitrogen hosts have been reconstructed from the isothermal section of the ternary phase diagram for the FeO-Fe3C-Fe3N system. The results of experiments at 7.8 GPa and 1350 °C show that oxygen increase in the system to > 0.5 wt % provides the stability of FeO and leads to changes in the phase diagram: the Fe3C, L, and Fe3N single-phase fields change to two-phase ones, while the Fe3C + L and Fe3N + L two-phase fields become three-phase. Сarbon in iron carbide (Fe3C, space group Pnma) is slightly below the ideal value and nitrogen is below the EMPA (Electron microprobe analysis) detection limit. Iron nitride (ε-Fe3N, space group P63/mmc) contains up to 2.7 wt % С and 4.4 wt % N in equilibrium with both melt and wüstite but 2.1 wt % С and 5.4 wt % N when equilibrated with wüstite alone. Impurities in wüstite (space group Fmm) are within the EMPA detection limit. The contents of oxygen, carbon, and nitrogen in the metal melt equilibrated with different iron compounds are within 0.5–0.8 wt % O even in FeO-rich samples; 3.8 wt % C and 1.2 wt % N for Fe3C + FeO; and 2.9 wt % C and 3.5 wt % N for Fe3N + FeO. Co-crystallization of Fe3C and Fe3N from the O-bearing metal melt is impossible because the fields of associated C- and N-rich compounds are separated by that of FeO + L. Additional experiments with excess oxygen added to the system show that metal melt, which is the main host of carbon and nitrogen in the metal-saturated (~0.1 wt %) mantle at a depth of ~250 km and a normal heat flux of 40 mW/m2, has the greatest oxygen affinity. Its partial oxidation produces FeO and causes crystallization of iron carbides (Fe3C and Fe7C3) and increases the nitrogen enrichment of the residual melt. Thus, the oxidation of metal melt in the mantle enriched in volatiles may lead to successive crystallization of iron carbides and nitrides. In these conditions, magnetite remains unstable till complete oxidation of iron carbide, iron nitride, and the melt. Iron carbides and nitrides discovered as inclusions in mantle diamonds may result from partial oxidation of metal melt which originally contained relatively low concentrations of carbon and nitrogen.
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19
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Sossi PA, Burnham AD, Badro J, Lanzirotti A, Newville M, O'Neill HSC. Redox state of Earth's magma ocean and its Venus-like early atmosphere. SCIENCE ADVANCES 2020; 6:6/48/eabd1387. [PMID: 33239296 PMCID: PMC7688334 DOI: 10.1126/sciadv.abd1387] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/07/2020] [Indexed: 05/24/2023]
Abstract
Exchange between a magma ocean and vapor produced Earth's earliest atmosphere. Its speciation depends on the oxygen fugacity (fO2) set by the Fe3+/Fe2+ ratio of the magma ocean at its surface. Here, we establish the relationship between fO2 and Fe3+/Fe2+ in quenched liquids of silicate Earth-like composition at 2173 K and 1 bar. Mantle-derived rocks have Fe3+/(Fe3++Fe2+) = 0.037 ± 0.005, at which the magma ocean defines an fO2 0.5 log units above the iron-wüstite buffer. At this fO2, the solubilities of H-C-N-O species in the magma ocean produce a CO-rich atmosphere. Cooling and condensation of H2O would have led to a prebiotic terrestrial atmosphere composed of CO2-N2, in proportions and at pressures akin to those observed on Venus. Present-day differences between Earth's atmosphere and those of her planetary neighbors result from Earth's heliocentric location and mass, which allowed geologically long-lived oceans, in-turn facilitating CO2 drawdown and, eventually, the development of life.
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Affiliation(s)
- Paolo A Sossi
- Institute of Geochemistry and Petrology, ETH Zürich, Sonneggstrasse 5, CH-8092 Zürich, Switzerland.
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, 75005 Paris, France
| | - Antony D Burnham
- Research School of Earth Sciences, Australian National University, 61 Mills Rd, 2601 Canberra, Australia
| | - James Badro
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, 75005 Paris, France
| | - Antonio Lanzirotti
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, USA
| | - Matt Newville
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, USA
| | - Hugh St C O'Neill
- Research School of Earth Sciences, Australian National University, 61 Mills Rd, 2601 Canberra, Australia
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20
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Fukuyama K, Kagi H, Inoue T, Kakizawa S, Shinmei T, Hishita S, Takahata N, Sano Y. High nitrogen solubility in stishovite (SiO 2) under lower mantle conditions. Sci Rep 2020; 10:10897. [PMID: 32616729 PMCID: PMC7331719 DOI: 10.1038/s41598-020-67621-2] [Citation(s) in RCA: 3] [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: 02/07/2020] [Accepted: 06/05/2020] [Indexed: 11/09/2022] Open
Abstract
Nitrogen is a crucial volatile element in the early Earth's evolution and the origin of life. Despite its importance, nitrogen's behavior in the Earth's interior remains poorly understood. Compared to other volatile elements, nitrogen is depleted in the Earth's atmosphere (the so-called "missing nitrogen"), calling for a hidden deep reservoir. To investigate nitrogen's behavior in the deep Earth including how the reservoir formed, high-pressure and high-temperature experiments were conducted at 28 GPa and 1,400-1,700 °C. To reproduce the conditions in the lower mantle, the redox was controlled using a Fe-FeO buffer. We observed that depending on the temperature conditions, stishovite can incorporate up to 90-404 ppm nitrogen, experimentally demonstrating that stishovite has the highest nitrogen solubility among the deep mantle minerals. Stishovite is the main mineral component of subducted nitrogen-rich sedimentary rocks and eroded continental crust that are eventually transported down to the lower mantle. Our results suggest that nitrogen could have been continuously transported into the lower mantle via subduction, ever since plate tectonics began.
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Affiliation(s)
- Ko Fukuyama
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, Hongo, Tokyo, 113-0033, Japan.
| | - Hiroyuki Kagi
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, Hongo, Tokyo, 113-0033, Japan.
| | - Toru Inoue
- Department of Earth and Planetary Systems Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
- Geodynamics Research Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Sho Kakizawa
- Geochemical Research Center, Graduate School of Science, The University of Tokyo, Hongo, Tokyo, 113-0033, Japan
- Department of Earth and Planetary Systems Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Toru Shinmei
- Geodynamics Research Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Shunichi Hishita
- Research and Services Division of Materials Data and Integrated System, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0047, Japan
| | - Naoto Takahata
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, 277-8564, Japan
| | - Yuji Sano
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, 277-8564, Japan
- Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, People's Republic of China
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21
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Abstract
Earth's core is likely the largest reservoir of carbon (C) in the planet, but its C abundance has been poorly constrained because measurements of carbon's preference for core versus mantle materials at the pressures and temperatures of core formation are lacking. Using metal-silicate partitioning experiments in a laser-heated diamond anvil cell, we show that carbon becomes significantly less siderophile as pressures and temperatures increase to those expected in a deep magma ocean during formation of Earth's core. Based on a multistage model of core formation, the core likely contains a maximum of 0.09(4) to 0.20(10) wt% C, making carbon a negligible contributor to the core's composition and density. However, this accounts for ∼80 to 90% of Earth's overall carbon inventory, which totals 370(150) to 740(370) ppm. The bulk Earth's carbon/sulfur ratio is best explained by the delivery of most of Earth's volatiles from carbonaceous chondrite-like precursors.
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22
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Palyanov YN, Borzdov YM, Khokhryakov AF, Bataleva YV, Kupriyanov IN. Effect of sulfur on diamond growth and morphology in metal–carbon systems. CrystEngComm 2020. [DOI: 10.1039/d0ce00865f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sulfur additives inhibit diamond crystallization in the Fe–Ni–C system at 6 GPa and 1400 °C and affect the diamond crystal morphology and nitrogen impurity content.
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Affiliation(s)
- Yuri N. Palyanov
- Sobolev Institute of Geology and Mineralogy
- Siberian Branch of the Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Yuri M. Borzdov
- Sobolev Institute of Geology and Mineralogy
- Siberian Branch of the Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
| | - Alexander F. Khokhryakov
- Sobolev Institute of Geology and Mineralogy
- Siberian Branch of the Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Yuliya V. Bataleva
- Sobolev Institute of Geology and Mineralogy
- Siberian Branch of the Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
| | - Igor N. Kupriyanov
- Sobolev Institute of Geology and Mineralogy
- Siberian Branch of the Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
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23
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Dalou C, Füri E, Deligny C, Piani L, Caumon MC, Laumonier M, Boulliung J, Edén M. Redox control on nitrogen isotope fractionation during planetary core formation. Proc Natl Acad Sci U S A 2019; 116:14485-14494. [PMID: 31262822 PMCID: PMC6642344 DOI: 10.1073/pnas.1820719116] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The present-day nitrogen isotopic compositions of Earth's surficial (15N-enriched) and deep reservoirs (15N-depleted) differ significantly. This distribution can neither be explained by modern mantle degassing nor recycling via subduction zones. As the effect of planetary differentiation on the behavior of N isotopes is poorly understood, we experimentally determined N-isotopic fractionations during metal-silicate partitioning (analogous to planetary core formation) over a large range of oxygen fugacities (ΔIW -3.1 < logfO2 < ΔIW -0.5, where ΔIW is the logarithmic difference between experimental oxygen fugacity [fO2] conditions and that imposed by the coexistence of iron and wüstite) at 1 GPa and 1,400 °C. We developed an in situ analytical method to measure the N-elemental and -isotopic compositions of experimental run products composed of Fe-C-N metal alloys and basaltic melts. Our results show substantial N-isotopic fractionations between metal alloys and silicate glasses, i.e., from -257 ± 22‰ to -49 ± 1‰ over 3 log units of fO2 These large fractionations under reduced conditions can be explained by the large difference between N bonding in metal alloys (Fe-N) and in silicate glasses (as molecular N2 and NH complexes). We show that the δ15N value of the silicate mantle could have increased by ∼20‰ during core formation due to N segregation into the core.
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Affiliation(s)
- Celia Dalou
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, CNRS-Université de Lorraine, 54501 Vandoeuvre-lès-Nancy Cedex, France;
| | - Evelyn Füri
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, CNRS-Université de Lorraine, 54501 Vandoeuvre-lès-Nancy Cedex, France
| | - Cécile Deligny
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, CNRS-Université de Lorraine, 54501 Vandoeuvre-lès-Nancy Cedex, France
| | - Laurette Piani
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, CNRS-Université de Lorraine, 54501 Vandoeuvre-lès-Nancy Cedex, France
| | | | - Mickael Laumonier
- 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
| | - Julien Boulliung
- Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, CNRS-Université de Lorraine, 54501 Vandoeuvre-lès-Nancy Cedex, France
| | - Mattias Edén
- Physical Chemistry Division, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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24
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Grewal DS, Dasgupta R, Holmes AK, Costin G, Li Y, Tsuno K. The fate of nitrogen during core-mantle separation on Earth. GEOCHIMICA ET COSMOCHIMICA ACTA 2019; 251:87-115. [PMID: 35153302 PMCID: PMC8833147 DOI: 10.1016/j.gca.2019.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nitrogen, the most dominant constituent of Earth's atmosphere, is critical for the habitability and existence of life on our planet. However, its distribution between Earth's major reservoirs, which must be largely influenced by the accretion and differentiation processes during its formative years, is poorly known. Sequestration into the metallic core, along with volatility related loss pre- and post-accretion, could be a critical process that can explain the depletion of nitrogen in the Bulk Silicate Earth (BSE) relative to the primitive chondrites. However, the relative effect of different thermodynamic parameters on the alloy-silicate partitioning behavior of nitrogen is still poorly known. Here we present equilibrium partitioning data of N between alloy and silicate melt ( D N alloy / silicate ) from 67 new high pressure (P = 1-6 GPa)-temperature (T = 1500-2200 °C) experiments under graphite saturated conditions at a wide range of oxygen fugacity (logfO2 ~ΔIW - 4.2 to - 0.8), mafic to ultramafic silicate melt compositions (NBO/T = 0.4 to 2.2), and varying chemical composition of the alloy melts (S and Si contents of 0-32.1 wt.% and 0-3.1 wt.%, respectively). Under relatively oxidizing conditions (~ΔIW - 2.2 to - 0.8) nitrogen acts as a siderophile element ( D N alloy / silicate between 1.1 and 52), where D N alloy / silicate decreases with decrease in fO2 and increase in T, and increases with increase in P and NBO/T. Under these conditions D N alloy / silicate remains largely unaffected between S-free conditions and up to ~17 wt.% S content in the alloy melt, and then drops off at > ~20 wt.% S content in the alloy melt. Under increasingly reduced conditions (< ~ ΔIW - 2.2), N becomes increasingly lithophile ( D N alloy / silicate between 0.003 and 0.5) with D N alloy / silicate decreasing with decrease in fO2 and increase in T. At these conditions fO2, along with Si content of the alloy under the most reduced conditions (< ~ΔIW - 3.0), is the controlling parameter with T playing a secondary role, while, P, NBO/T, and S content of the alloy have minimal effects. A multiple linear least-squares regression parametrization for D N alloy / silicate based on the results of this study and previous studies suggests, in agreement with the experimental data, that fO2 (represented by Si content of the alloy melt and FeO content of the silicate melt), followed by T, has the strongest control on D N alloy / silicate . Based on our modeling, to match the present-day BSE N content, impactors that brought N must have been moderately to highly oxidized. If N bearing impactors were reduced, and/or there was significant disequilibrium core formation, then the BSE would be too N-rich and another mechanism for N loss, such as atmospheric loss, would be required.
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Affiliation(s)
- Damanveer S. Grewal
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
| | - Rajdeep Dasgupta
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
| | - Alexandra K. Holmes
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
| | - Gelu Costin
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
| | - Yuan Li
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510460, China
| | - Kyusei Tsuno
- Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, TX 77005, USA
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