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Avdellidou C, Delbo' M, Nesvorný D, Walsh KJ, Morbidelli A. Dating the Solar System's giant planet orbital instability using enstatite meteorites. Science 2024; 384:348-352. [PMID: 38624242 DOI: 10.1126/science.adg8092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/16/2024] [Indexed: 04/17/2024]
Abstract
The giant planets of the Solar System formed on initially compact orbits, which transitioned to the current wider configuration by means of an orbital instability. The timing of that instability is poorly constrained. In this work, we use dynamical simulations to demonstrate that the instability implanted planetesimal fragments from the terrestrial planet region into the asteroid main belt. We use meteorite data to show that the implantation occurred >60 million years (Myr) after the Solar System began to form. Combining this constraint with a previous upper limit derived from Jupiter's trojan asteroids, we conclude that the orbital instability occurred 60 to 100 Myr after the beginning of Solar System formation. The giant impact that formed the Moon occurred within this range, so it might be related to the giant planet instability.
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Affiliation(s)
- Chrysa Avdellidou
- Laboratoire Lagrange, Centre National de la Recherche Scientifique, Observatoire de la Côte d'Azur, Université Côte d'Azur, 06304 Nice, France
- School of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
| | - Marco Delbo'
- Laboratoire Lagrange, Centre National de la Recherche Scientifique, Observatoire de la Côte d'Azur, Université Côte d'Azur, 06304 Nice, France
- School of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
| | | | - Kevin J Walsh
- Southwest Research Institute, Boulder, CO 80302, USA
| | - Alessandro Morbidelli
- Laboratoire Lagrange, Centre National de la Recherche Scientifique, Observatoire de la Côte d'Azur, Université Côte d'Azur, 06304 Nice, France
- Collège de France, Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, Sorbonne Université, 75014 Paris, France
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2
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A Review of the Lunar 182Hf-182W Isotope System Research. MINERALS 2022. [DOI: 10.3390/min12060759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In recent years, the extinct nuclide 182Hf-182W system has been developed as an essential tool to date and trace the lunar origin and evolution. Despite a series of achievements, controversies and problems exist. As a review, this paper details the application principles of the 182Hf-182W isotope system and summarizes the research development on W isotopes of the Moon. A significant radiogenic ε182W excess of 0.24 ± 0.01 was found in the lunar mantle, leading to heated debates. There are three main explanations for the origin of the excess, including (1) radioactive origin; (2) the mantle of the Moon-forming impactor; and (3) disproportional late accretion to the Earth and the Moon. Debates on these explanations have revealed different views on lunar age. The reported ages of the Moon are mainly divided into two views: an early Moon (30–70 Ma after the solar system formation); and a late Moon (>70 Ma after the solar system formation). This paper discusses the possible effects on lunar 182W composition, including the Moon-forming impactor, late veneer, and Oceanus Procellarum-forming projectile. Finally, the unexpected isotopic similarities between the Earth and Moon are discussed.
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3
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Early Solar System instability triggered by dispersal of the gaseous disk. Nature 2022; 604:643-646. [PMID: 35478235 DOI: 10.1038/s41586-022-04535-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/08/2022] [Indexed: 11/08/2022]
Abstract
The Solar System's orbital structure is thought to have been sculpted by an episode of dynamical instability among the giant planets1-4. However, the instability trigger and timing have not been clearly established5-9. Hydrodynamical modelling has shown that while the Sun's gaseous protoplanetary disk was present the giant planets migrated into a compact orbital configuration in a chain of resonances2,10. Here we use dynamical simulations to show that the giant planets' instability was probably triggered by the dispersal of the gaseous disk. As the disk evaporated from the inside out, its inner edge swept successively across and dynamically perturbed each planet's orbit in turn. The associated orbital shift caused a dynamical compression of the exterior part of the system, ultimately triggering instability. The final orbits of our simulated systems match those of the Solar System for a viable range of astrophysical parameters. The giant planet instability therefore took place as the gaseous disk dissipated, constrained by astronomical observations to be a few to ten million years after the birth of the Solar System11. Terrestrial planet formation would not complete until after such an early giant planet instability12,13; the growing terrestrial planets may even have been sculpted by its perturbations, explaining the small mass of Mars relative to Earth14.
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4
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Barth P, Carone L, Barnes R, Noack L, Mollière P, Henning T. Magma Ocean Evolution of the TRAPPIST-1 Planets. ASTROBIOLOGY 2021; 21:1325-1349. [PMID: 34314604 DOI: 10.1089/ast.2020.2277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent observations of the potentially habitable planets TRAPPIST-1 e, f, and g suggest that they possess large water mass fractions of possibly several tens of weight percent of water, even though the host star's activity should drive rapid atmospheric escape. These processes can photolyze water, generating free oxygen and possibly desiccating the planet. After the planets formed, their mantles were likely completely molten with volatiles dissolving and exsolving from the melt. To understand these planets and prepare for future observations, the magma ocean phase of these worlds must be understood. To simulate these planets, we have combined existing models of stellar evolution, atmospheric escape, tidal heating, radiogenic heating, magma-ocean cooling, planetary radiation, and water-oxygen-iron geochemistry. We present MagmOc, a versatile magma-ocean evolution model, validated against the rocky super-Earth GJ 1132b and early Earth. We simulate the coupled magma-ocean atmospheric evolution of TRAPPIST-1 e, f, and g for a range of tidal and radiogenic heating rates, as well as initial water contents between 1 and 100 Earth oceans. We also reanalyze the structures of these planets and find they have water mass fractions of 0-0.23, 0.01-0.21, and 0.11-0.24 for planets e, f, and g, respectively. Our model does not make a strong prediction about the water and oxygen content of the atmosphere of TRAPPIST-1 e at the time of mantle solidification. In contrast, the model predicts that TRAPPIST-1 f and g would have a thick steam atmosphere with a small amount of oxygen at that stage. For all planets that we investigated, we find that only 3-5% of the initial water will be locked in the mantle after the magma ocean solidified.
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Affiliation(s)
- Patrick Barth
- Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
- SUPA, School of Physics & Astronomy, University of St Andrews, St Andrews, UK
- Max Planck Institute for Astronomy, Heidelberg, Germany
| | | | - Rory Barnes
- Astronomy Department, University of Washington, Seattle, Washington, USA
- NASA Virtual Planetary Laboratory Lead Team, USA
| | - Lena Noack
- Freie Universität Berlin, Institute of Geological Sciences, Berlin, Germany
| | - Paul Mollière
- Max Planck Institute for Astronomy, Heidelberg, Germany
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5
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Shi X, Castillo-Rogez J, Hsieh H, Hui H, Ip WH, Lei H, Li JY, Tosi F, Zhou L, Agarwal J, Barucci A, Beck P, Bagatin AC, Capaccioni F, Coates AJ, Cremonese G, Duffard R, Grande M, Jaumann R, Jones GH, Kallio E, Lin Y, Mousis O, Nathues A, Oberst J, Sierks H, Ulamec S, Wang M. GAUSS - genesis of asteroids and evolution of the solar system: A sample return mission to Ceres. EXPERIMENTAL ASTRONOMY 2021; 54:713-744. [PMID: 36915624 PMCID: PMC9998589 DOI: 10.1007/s10686-021-09800-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/23/2021] [Indexed: 06/18/2023]
Abstract
The goal of Project GAUSS (Genesis of Asteroids and evolUtion of the Solar System) is to return samples from the dwarf planet Ceres. Ceres is the most accessible candidate of ocean worlds and the largest reservoir of water in the inner Solar System. It shows active volcanism and hydrothermal activities in recent history. Recent evidence for the existence of a subsurface ocean on Ceres and the complex geochemistry suggest past habitability and even the potential for ongoing habitability. GAUSS will return samples from Ceres with the aim of answering the following top-level scientific questions: What is the origin of Ceres and what does this imply for the origin of water and other volatiles in the inner Solar System?What are the physical properties and internal structure of Ceres? What do they tell us about the evolutionary and aqueous alteration history of dwarf planets?What are the astrobiological implications of Ceres? Is it still habitable today?What are the mineralogical connections between Ceres and our current collections of carbonaceous meteorites?
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Affiliation(s)
- Xian Shi
- Max Planck Institute for Solar System Research, Göttingen, Germany
- Present Address: Shanghai Astronomical Observatory, Shanghai, China
| | | | | | - Hejiu Hui
- School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Wing-Huen Ip
- Institute of Astronomy and Space Science, National Central University, Chung Li, Taiwan
| | - Hanlun Lei
- School of Astronomy and Space Science, Nanjing University, Nanjing, China
| | | | - Federico Tosi
- Istituto Nazionale di AstroFisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Liyong Zhou
- School of Astronomy and Space Science, Nanjing University, Nanjing, China
| | - Jessica Agarwal
- Max Planck Institute for Solar System Research, Göttingen, Germany
- Institute for Geophysics and Extraterrestrial Physics, Technical University Braunschweig, Braunschweig, Germany
| | - Antonella Barucci
- LESIA-Observatoire de Paris, Université PSL, CNRS, Université de Paris, Sorbonne Université, F-92195 Meudon, Principal Cedex, France
| | - Pierre Beck
- CNRS Institut de Planétologie et d’Astrophysique, Univ. Grenoble Alpes, Grenoble, France
| | - Adriano Campo Bagatin
- Universidad de Alicante, Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Alicante, Spain
| | - Fabrizio Capaccioni
- Istituto Nazionale di AstroFisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Andrew J. Coates
- Mullard Space Science Laboratory, University College London, Surrey, UK
| | | | - Rene Duffard
- Instituto de Astrofísica de Andalucía (CSIC), Granada, Spain
| | | | - Ralf Jaumann
- Institute of Geological Sciences, Free University of Berlin, Berlin, Germany
| | - Geraint H. Jones
- Mullard Space Science Laboratory, University College London, Surrey, UK
| | - Esa Kallio
- School of Electrical Engineering, Aalto University, Aalto, Finland
| | - Yangting Lin
- Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | | | - Andreas Nathues
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Jürgen Oberst
- DLR Institute of Planetary Research, Berlin, Germany
| | - Holger Sierks
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Stephan Ulamec
- DLR Space Operations and Astronaut Training, Cologne, Germany
| | - Mingyuan Wang
- National Astronomical Observatory, Chinese Academy of Science, Beijing, China
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6
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Gebauer S, Grenfell JL, Lammer H, de Vera JPP, Sproß L, Airapetian VS, Sinnhuber M, Rauer H. Atmospheric Nitrogen When Life Evolved on Earth. ASTROBIOLOGY 2020; 20:1413-1426. [PMID: 33121251 DOI: 10.1089/ast.2019.2212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The amount of nitrogen (N2) present in the atmosphere when life evolved on our planet is central for understanding the production of prebiotic molecules and, hence, is a fundamental quantity to constrain. Estimates of atmospheric molecular nitrogen partial surface pressures during the Archean, however, widely vary in the literature. In this study, we apply a model that combines newly gained insights into atmospheric escape, magma ocean duration, and outgassing evolution. Results suggest <420 mbar surface molecular nitrogen at the time when life originated, which is much lower compared with estimates in previous works and hence could impact our understanding of the production rate of prebiotic molecules such as hydrogen cyanide. Our revised values provide new input for atmospheric chamber experiments that simulate prebiotic chemistry on the early Earth. Our results that assume negligible nitrogen escape rates are in agreement with research based on solidified gas bubbles and the oxidation of iron in micrometeorites at 2.7 Gyr ago, which suggest that the atmospheric pressure was probably less than half the present-day value. Our results contradict previous studies that assume N2 partial surface pressures during the Archean were higher than those observed today and suggest that, if the N2 partial pressure were low in the Archean, it would likely be low in the Hadean as well. Furthermore, our results imply a biogenic nitrogen fixation rate from 9 to 14 Teragram N2 per year (Tg N2/year), which is consistent with modern marine biofixation rates and, hence, indicate an oceanic origin of this fixation process.
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Affiliation(s)
- Stefanie Gebauer
- Institute for Planetary Research (PF), German Aerospace Centre (DLR), Berlin, Germany
| | - John Lee Grenfell
- Institute for Planetary Research (PF), German Aerospace Centre (DLR), Berlin, Germany
| | - Helmut Lammer
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | | | - Laurenz Sproß
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
- Institute for Physics, University of Graz, Graz, Austria
| | - Vladimir S Airapetian
- NASA Goddard Space Flight Center (GSFC), Greenbelt, Maryland, USA
- American University, NW Washington, District of Columbia, USA
| | - Miriam Sinnhuber
- Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Heike Rauer
- Institute for Planetary Research (PF), German Aerospace Centre (DLR), Berlin, Germany
- Institute for Geological Sciences, Planetology and Remote Sensing, Freie Universität Berlin (FUB), Berlin, Germany
- Centre for Astronomy and Astrophysics, Technische Universität Berlin (TUB), Berlin, Germany
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7
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Maurice M, Tosi N, Schwinger S, Breuer D, Kleine T. A long-lived magma ocean on a young Moon. SCIENCE ADVANCES 2020; 6:eaba8949. [PMID: 32695879 PMCID: PMC7351470 DOI: 10.1126/sciadv.aba8949] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/28/2020] [Indexed: 05/31/2023]
Abstract
A giant impact onto Earth led to the formation of the Moon, resulted in a lunar magma ocean (LMO), and initiated the last event of core segregation on Earth. However, the timing and temporal link of these events remain uncertain. Here, we demonstrate that the low thermal conductivity of the lunar crust combined with heat extraction by partial melting of deep cumulates undergoing convection results in an LMO solidification time scale of 150 to 200 million years. Combining this result with a crystallization model of the LMO and with the ages and isotopic compositions of lunar samples indicates that the Moon formed 4.425 ± 0.025 billion years ago. This age is in remarkable agreement with the U-Pb age of Earth, demonstrating that the U-Pb age dates the final segregation of Earth's core.
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Affiliation(s)
- M. Maurice
- German Aerospace Center (DLR), Rutherfordstr. 2, 12489 Berlin, Germany
- Department of Astronomy and Astrophysics, Technische Universität Berlin, Berlin, Germany
| | - N. Tosi
- German Aerospace Center (DLR), Rutherfordstr. 2, 12489 Berlin, Germany
- Department of Astronomy and Astrophysics, Technische Universität Berlin, Berlin, Germany
| | - S. Schwinger
- German Aerospace Center (DLR), Rutherfordstr. 2, 12489 Berlin, Germany
| | - D. Breuer
- German Aerospace Center (DLR), Rutherfordstr. 2, 12489 Berlin, Germany
| | - T. Kleine
- Institut für Planetologie, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
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8
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Zube NG, Nimmo F, Fischer RA, Jacobson SA. Constraints on terrestrial planet formation timescales and equilibration processes in the Grand Tack scenario from Hf-W isotopic evolution. EARTH AND PLANETARY SCIENCE LETTERS 2019; 522:210-218. [PMID: 32636530 PMCID: PMC7339907 DOI: 10.1016/j.epsl.2019.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We examine 141 N-body simulations of terrestrial planet late-stage accretion that use the Grand Tack scenario, coupling the collisional results with a hafnium-tungsten (Hf-W) isotopic evolution model. Accretion in the Grand Tack scenario results in faster planet formation than classical accretion models because of higher planetesimal surface density induced by a migrating Jupiter. Planetary embryos which grow rapidly experience radiogenic ingrowth of mantle tungsten which is inconsistent with the measured terrestrial value, unless much of the tungsten is removed by an impactor core that mixes thoroughly with the target mantle. For physically Earth-like surviving planets, we find that the fraction of equilibrating impactor core kcore ≥ 0.6 is required to produce results agreeing with observed terrestrial tungsten anomalies (assuming equilibration with relatively large volumes of target mantle material; smaller equilibrating mantle volumes would require even larger kcore ). This requirement of substantial core re-equilibration may be difficult to reconcile with fluid dynamical predictions and hydrocode simulations of mixing during large impacts, and hence this result disfavors the rapid planet building of Grand Tack accretion.
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Affiliation(s)
- Nicholas G. Zube
- University of California Santa Cruz, Dept. of Earth and Planetary Sciences, 1156 High St., Santa Cruz, CA 95064, USA
| | - Francis Nimmo
- University of California Santa Cruz, Dept. of Earth and Planetary Sciences, 1156 High St., Santa Cruz, CA 95064, USA
| | - Rebecca A. Fischer
- Harvard University, Dept. Earth and Planetary Sciences, 20 Oxford St., Cambridge, MA 02138, USA
| | - Seth A. Jacobson
- Northwestern University, Dept. Earth and Planetary Sciences, 2145 Sheridan Road, Evanston, IL 60208, USA
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9
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Rare Earth Elements in Planetary Crusts: Insights from Chemically Evolved Igneous Suites on Earth and the Moon. MINERALS 2018. [DOI: 10.3390/min8100455] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The abundance of the rare earth elements (REEs) in Earth’s crust has become the intense focus of study in recent years due to the increasing societal demand for REEs, their increasing utilization in modern-day technology, and the geopolitics associated with their global distribution. Within the context of chemically evolved igneous suites, 122 REE deposits have been identified as being associated with intrusive dike, granitic pegmatites, carbonatites, and alkaline igneous rocks, including A-type granites and undersaturated rocks. These REE resource minerals are not unlimited and with a 5–10% growth in global demand for REEs per annum, consideration of other potential REE sources and their geological and chemical associations is warranted. The Earth’s moon is a planetary object that underwent silicate-metal differentiation early during its history. Following ~99% solidification of a primordial lunar magma ocean, residual liquids were enriched in potassium, REE, and phosphorus (KREEP). While this reservoir has not been directly sampled, its chemical signature has been identified in several lunar lithologies and the Procellarum KREEP Terrane (PKT) on the lunar nearside has an estimated volume of KREEP-rich lithologies at depth of 2.2 × 108 km3. This reservoir therefore offers a prospective location for future lunar REE exploration. Within the context of chemically evolved lithologies, lunar granites are rare with only 22 samples currently classified as granitic. However, these extraterrestrial granites exhibit chemical affinities to terrestrial A-type granites. On Earth, these anorogenic magmatic systems are hosts to U-Th-REE-ore deposits and while to date only U-Th regions of enrichment on the lunar surface have been identified, future exploration of the lunar surface and interior may yet reveal U-Th-REE regions associated with the distribution of these chemically distinct, evolved lithologies.
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10
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Fischer RA, Nimmo F. Effects of core formation on the Hf-W isotopic composition of the Earth and dating of the Moon-forming impact. EARTH AND PLANETARY SCIENCE LETTERS 2018; 499:257-265. [PMID: 31213724 PMCID: PMC6581455 DOI: 10.1016/j.epsl.2018.07.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Earth's core formation set the initial compositions of the core and mantle. Various aspects of core formation, such as the degree of metal-silicate equilibration, oxygen fugacity, and depth of equilibration, have significant consequences for the resulting compositions, yet are poorly constrained. The Hf-W isotopic system can provide unique constraints on these aspects relative to other geochemical or geophysical methods. Here we model the Hf-W isotopic evolution of the Earth, improving over previous studies by combining a large number of N-body simulations of planetary accretion with a core formation model that includes self-consistent evolution of oxygen fugacity and a partition coefficient of tungsten that evolves with changing pressure, temperature, composition, and oxygen fugacity. The effective average fraction of equilibrating metal is constrained to be k > 0.2 for a range of equilibrating silicate masses (for canonical accretion scenarios), and is likely <0.55 if the Moon formed later than 65 Ma. These values of k typically correspond to an effective equilibration depth of ~0.5-0.7× the evolving core-mantle boundary pressure as the planet grows. The average mass of equilibrating silicate was likely at least 3× the impactor's silicate mass. Equilibration temperature, initial fO2 initial differentiation time, semimajor axis, and planetary mass (above ~0.9 M⊕) have no systematic effect on the 182W anomaly, or on f Hf/W (except for fO2), when applying the constraint that the model must reproduce Earth's mantle W abundance. There are strong tradeoffs between the effects of k, equilibrating silicate mass, depth of equilibration, and timing of core formation, so the terrestrial Hf-W isotopic system should be interpreted with caution when used as a chronometer of Earth's core formation. Because of these strong tradeoffs, the Earth's tungsten anomaly can be reproduced for Moon-forming impact timescales spanning at least 10-175 Ma. Early Moon formation ages require a higher degree of metal-silicate equilibration to produce Earth's 182W anomaly.
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Affiliation(s)
- Rebecca A. Fischer
- Harvard University, Department of Earth and Planetary
Sciences
- University of California Santa Cruz, Department of Earth
and Planetary Science
- Smithsonian National Museum of Natural History, Department
of Mineral Sciences
- Corresponding author.
. Phone: 617.384.6992
| | - Francis Nimmo
- University of California Santa Cruz, Department of Earth
and Planetary Science
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11
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Pearce BKD, Tupper AS, Pudritz RE, Higgs PG. Constraining the Time Interval for the Origin of Life on Earth. ASTROBIOLOGY 2018; 18:343-364. [PMID: 29570409 DOI: 10.1089/ast.2017.1674] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Estimates of the time at which life arose on Earth make use of two types of evidence. First, astrophysical and geophysical studies provide a timescale for the formation of Earth and the Moon, for large impact events on early Earth, and for the cooling of the early magma ocean. From this evidence, we can deduce a habitability boundary, which is the earliest point at which Earth became habitable. Second, biosignatures in geological samples, including microfossils, stromatolites, and chemical isotope ratios, provide evidence for when life was actually present. From these observations we can deduce a biosignature boundary, which is the earliest point at which there is clear evidence that life existed. Studies with molecular phylogenetics and records of the changing level of oxygen in the atmosphere give additional information that helps to determine the biosignature boundary. Here, we review the data from a wide range of disciplines to summarize current information on the timings of these two boundaries. The habitability boundary could be as early as 4.5 Ga, the earliest possible estimate of the time at which Earth had a stable crust and hydrosphere, or as late as 3.9 Ga, the end of the period of heavy meteorite bombardment. The lack of consensus on whether there was a late heavy meteorite bombardment that was significant enough to prevent life is the largest uncertainty in estimating the time of the habitability boundary. The biosignature boundary is more closely constrained. Evidence from carbon isotope ratios and stromatolite fossils both point to a time close to 3.7 Ga. Life must have emerged in the interval between these two boundaries. The time taken for life to appear could, therefore, be within 200 Myr or as long as 800 Myr. Key Words: Origin of life-Astrobiology-Habitability-Biosignatures-Geochemistry-Early Earth. Astrobiology 18, 343-364.
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Affiliation(s)
- Ben K D Pearce
- Origins Institute, Department of Physics and Astronomy, McMaster University , Hamilton, Canada
| | - Andrew S Tupper
- Origins Institute, Department of Physics and Astronomy, McMaster University , Hamilton, Canada
| | - Ralph E Pudritz
- Origins Institute, Department of Physics and Astronomy, McMaster University , Hamilton, Canada
| | - Paul G Higgs
- Origins Institute, Department of Physics and Astronomy, McMaster University , Hamilton, Canada
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12
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Nies DH. The biological chemistry of the transition metal "transportome" of Cupriavidus metallidurans. Metallomics 2017; 8:481-507. [PMID: 27065183 DOI: 10.1039/c5mt00320b] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review tries to illuminate how the bacterium Cupriavidus metallidurans CH34 is able to allocate essential transition metal cations to their target proteins although these metals have similar charge-to-surface ratios and chemical features, exert toxic effects, compete with each other, and occur in the bacterial environment over a huge range of concentrations and speciations. Central to this ability is the "transportome", the totality of all interacting metal import and export systems, which, as an emergent feature, transforms the environmental metal content and speciation into the cellular metal mélange. In a kinetic flow equilibrium resulting from controlled uptake and efflux reactions, the periplasmic and cytoplasmic metal content is adjusted in a way that minimizes toxic effects. A central core function of the transportome is to shape the metal ion composition using high-rate and low-specificity reactions to avoid time and/or energy-requiring metal discrimination reactions. This core is augmented by metal-specific channels that may even deliver metals all the way from outside of the cell to the cytoplasm. This review begins with a description of the basic chemical features of transition metal cations and the biochemical consequences of these attributes, and which transition metals are available to C. metallidurans. It then illustrates how the environment influences the metal content and speciation, and how the transportome adjusts this metal content. It concludes with an outlook on the fate of metals in the cytoplasm. By generalization, insights coming from C. metallidurans shed light on multiple transition metal homoeostatic mechanisms in all kinds of bacteria including pathogenic species, where the "battle" for metals is an important part of the host-pathogen interaction.
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Affiliation(s)
- Dietrich H Nies
- Molecular Microbiology, Institute for Biology/Microbiology, Martin-Luther-University Halle-Wittenberg, Germany.
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13
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Rubie DC, Laurenz V, Jacobson SA, Morbidelli A, Palme H, Vogel AK, Frost DJ. Highly siderophile elements were stripped from Earth's mantle by iron sulfide segregation. Science 2017; 353:1141-4. [PMID: 27609889 DOI: 10.1126/science.aaf6919] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 08/17/2016] [Indexed: 11/02/2022]
Abstract
Highly siderophile elements (HSEs) are strongly depleted in the bulk silicate Earth (BSE) but are present in near-chondritic relative abundances. The conventional explanation is that the HSEs were stripped from the mantle by the segregation of metal during core formation but were added back in near-chondritic proportions by late accretion, after core formation had ceased. Here we show that metal-silicate equilibration and segregation during Earth's core formation actually increased HSE mantle concentrations because HSE partition coefficients are relatively low at the high pressures of core formation within Earth. The pervasive exsolution and segregation of iron sulfide liquid from silicate liquid (the "Hadean matte") stripped magma oceans of HSEs during cooling and crystallization, before late accretion, and resulted in slightly suprachondritic palladium/iridium and ruthenium/iridium ratios.
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Affiliation(s)
| | | | - Seth A Jacobson
- Bayerisches Geoinstitut, Bayreuth, Germany. Observatoire de la Cote d'Azur, Nice, France
| | | | - Herbert Palme
- Forschungsinstitut und Naturmuseum Senckenberg, Frankfurt, Germany
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Barboni M, Boehnke P, Keller B, Kohl IE, Schoene B, Young ED, McKeegan KD. Early formation of the Moon 4.51 billion years ago. SCIENCE ADVANCES 2017; 3:e1602365. [PMID: 28097222 PMCID: PMC5226643 DOI: 10.1126/sciadv.1602365] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 11/29/2016] [Indexed: 05/19/2023]
Abstract
Establishing the age of the Moon is critical to understanding solar system evolution and the formation of rocky planets, including Earth. However, despite its importance, the age of the Moon has never been accurately determined. We present uranium-lead dating of Apollo 14 zircon fragments that yield highly precise, concordant ages, demonstrating that they are robust against postcrystallization isotopic disturbances. Hafnium isotopic analyses of the same fragments show extremely low initial 176Hf/177Hf ratios corrected for cosmic ray exposure that are near the solar system initial value. Our data indicate differentiation of the lunar crust by 4.51 billion years, indicating the formation of the Moon within the first ~60 million years after the birth of the solar system.
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Affiliation(s)
- Melanie Barboni
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Corresponding author.
| | - Patrick Boehnke
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of the Geophysical Sciences, The University of Chicago, Chicago, IL 60637, USA
| | - Brenhin Keller
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
- Berkeley Geochronology Center, Berkeley, CA 94709, USA
| | - Issaku E. Kohl
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Blair Schoene
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Edward D. Young
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kevin D. McKeegan
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
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Sleep NH. Asteroid bombardment and the core of Theia as possible sources for the Earth's late veneer component. GEOCHEMISTRY, GEOPHYSICS, GEOSYSTEMS : G(3) 2016; 17:2623-2642. [PMID: 35095346 PMCID: PMC8793101 DOI: 10.1002/2016gc006305] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The silicate Earth contains Pt-group elements in roughly chondritic relative ratios, but with absolute concentrations <1% chondrite. This veneer implies addition of chondrite-like material with 0.3-0.7% mass of the Earth's mantle or an equivalent planet-wide thickness of 5-20 km. The veneer thickness, 200-300 m, within the lunar crust and mantle is much less. One hypothesis is that the terrestrial veneer arrived after the moon-forming impact within a few large asteroids that happened to miss the smaller Moon. Alternatively, most of terrestrial veneer came from the core of the moon-forming impactor, Theia. The Moon then likely contains iron from Theia's core. Mass balances lend plausibility. The lunar core mass is ~1.6 × 1021 kg and the excess FeO component in the lunar mantle is 1.3-3.5 × 1021 kg as Fe, totaling 3-5 × 1021 kg or a few percent of Theia's core. This mass is comparable to the excess Fe of 2.3-10 × 1021 kg in the Earth's mantle inferred from the veneer component. Chemically in this hypothesis, Fe metal from Theia's core entered the Moon-forming disk. H2O and Fe2O3 in the disk oxidized part of the Fe, leaving the lunar mantle near a Fe-FeO buffer. The remaining iron metal condensed, gathered Pt-group elements eventually into the lunar core. The silicate Moon is strongly depleted in Pt-group elements. In contrast, the Earth's mantle contained excess oxidants, H2O and Fe2O3, which quantitatively oxidized the admixed Fe from Theia's core, retaining Pt-group elements. In this hypothesis, asteroid impacts were relatively benign with ~1 terrestrial event that left only thermophile survivors.
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Affiliation(s)
- Norman H Sleep
- Department of Geophysics, Stanford University, Stanford, California, USA
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The Cosmic Zoo: The (Near) Inevitability of the Evolution of Complex, Macroscopic Life. Life (Basel) 2016; 6:life6030025. [PMID: 27376334 PMCID: PMC5041001 DOI: 10.3390/life6030025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/17/2016] [Accepted: 06/22/2016] [Indexed: 12/31/2022] Open
Abstract
Life on Earth provides a unique biological record from single-cell microbes to technologically intelligent life forms. Our evolution is marked by several major steps or innovations along a path of increasing complexity from microbes to space-faring humans. Here we identify various major key innovations, and use an analytical toolset consisting of a set of models to analyse how likely each key innovation is to occur. Our conclusion is that once the origin of life is accomplished, most of the key innovations can occur rather readily. The conclusion for other worlds is that if the origin of life can occur rather easily, we should live in a cosmic zoo, as the innovations necessary to lead to complex life will occur with high probability given sufficient time and habitat. On the other hand, if the origin of life is rare, then we might live in a rather empty universe.
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Young ED, Kohl IE, Warren PH, Rubie DC, Jacobson SA, Morbidelli A. Oxygen isotopic evidence for vigorous mixing during the Moon-forming giant impact. Science 2016; 351:493-6. [PMID: 26823426 DOI: 10.1126/science.aad0525] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Earth and the Moon are shown here to have indistinguishable oxygen isotope ratios, with a difference in Δ'(17)O of -1 ± 5 parts per million (2 standard error). On the basis of these data and our new planet formation simulations that include a realistic model for primordial oxygen isotopic reservoirs, our results favor vigorous mixing during the giant impact and therefore a high-energy, high-angular-momentum impact. The results indicate that the late veneer impactors had an average Δ'(17)O within approximately 1 per mil of the terrestrial value, limiting possible sources for this late addition of mass to the Earth-Moon system.
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Affiliation(s)
- Edward D Young
- Department of Earth, Planetary, and Space Sciences, University of California Los Angeles, Los Angeles, CA, USA.
| | - Issaku E Kohl
- Department of Earth, Planetary, and Space Sciences, University of California Los Angeles, Los Angeles, CA, USA.
| | - Paul H Warren
- Department of Earth, Planetary, and Space Sciences, University of California Los Angeles, Los Angeles, CA, USA
| | - David C Rubie
- Bayerisches Geoinstitut, University of Bayreuth, D-95490 Bayreuth, Germany
| | - Seth A Jacobson
- Bayerisches Geoinstitut, University of Bayreuth, D-95490 Bayreuth, Germany. Laboratoire Lagrange, Université de Nice-Sophia Antipolis, Observatoire de la Cote d'Azur, CNRS, 06304 Nice, France
| | - Alessandro Morbidelli
- Laboratoire Lagrange, Université de Nice-Sophia Antipolis, Observatoire de la Cote d'Azur, CNRS, 06304 Nice, France
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Abstract
One key for understanding the stratification in the deep mantle lies in the determination of the density and structure of matter at high pressures, as well as the density contrast between solid and liquid silicate phases. Indeed, the density contrast is the main control on the entrainment or settlement of matter and is of fundamental importance for understanding the past and present dynamic behavior of the deepest part of the Earth's mantle. Here, we adapted the X-ray absorption method to the small dimensions of the diamond anvil cell, enabling density measurements of amorphous materials to unprecedented conditions of pressure. Our density data for MgSiO3 glass up to 127 GPa are considerably higher than those previously derived from Brillouin spectroscopy but validate recent ab initio molecular dynamics simulations. A fourth-order Birch-Murnaghan equation of state reproduces our experimental data over the entire pressure regime of the mantle. At the core-mantle boundary (CMB) pressure, the density of MgSiO3 glass is 5.48 ± 0.18 g/cm(3), which is only 1.6% lower than that of MgSiO3 bridgmanite at 5.57 g/cm(3), i.e., they are the same within the uncertainty. Taking into account the partitioning of iron into the melt, we conclude that melts are denser than the surrounding solid phases in the lowermost mantle and that melts will be trapped above the CMB.
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Genda H, Kobayashi H, Kokubo E. WARM DEBRIS DISKS PRODUCED BY GIANT IMPACTS DURING TERRESTRIAL PLANET FORMATION. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/810/2/136] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bottke WF, Vokrouhlický D, Marchi S, Swindle T, Scott ERD, Weirich JR, Levison H. Dating the Moon-forming impact event with asteroidal meteorites. Science 2015; 348:321-3. [DOI: 10.1126/science.aaa0602] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- W. F. Bottke
- Southwest Research Institute and NASA Solar System Exploration Research Virtual Institute (SSERVI)–Institute for the Science of Exploration Targets (ISET), Boulder, CO, USA
| | - D. Vokrouhlický
- Institute of Astronomy, Charles University, V Holešovičkách 2, CZ-18000, Prague 8, Czech Republic
| | - S. Marchi
- Southwest Research Institute and NASA Solar System Exploration Research Virtual Institute (SSERVI)–Institute for the Science of Exploration Targets (ISET), Boulder, CO, USA
| | - T. Swindle
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
- SSERVI Center for Lunar Science Exploration, Houston, TX, USA
| | - E. R. D. Scott
- Hawai’i Institute of Geophysics and Planetology, University of Hawai’i at Manoa, Honolulu, Hawai’i 96822, USA
| | - J. R. Weirich
- Department of Earth Sciences, Western University, London, ON, Canada
| | - H. Levison
- Southwest Research Institute and NASA Solar System Exploration Research Virtual Institute (SSERVI)–Institute for the Science of Exploration Targets (ISET), Boulder, CO, USA
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Jacobson SA, Morbidelli A. Lunar and terrestrial planet formation in the Grand Tack scenario. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130174. [PMID: 25114304 PMCID: PMC4128261 DOI: 10.1098/rsta.2013.0174] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We present conclusions from a large number of N-body simulations of the giant impact phase of terrestrial planet formation. We focus on new results obtained from the recently proposed Grand Tack model, which couples the gas-driven migration of giant planets to the accretion of the terrestrial planets. The giant impact phase follows the oligarchic growth phase, which builds a bi-modal mass distribution within the disc of embryos and planetesimals. By varying the ratio of the total mass in the embryo population to the total mass in the planetesimal population and the mass of the individual embryos, we explore how different disc conditions control the final planets. The total mass ratio of embryos to planetesimals controls the timing of the last giant (Moon-forming) impact and its violence. The initial embryo mass sets the size of the lunar impactor and the growth rate of Mars. After comparing our simulated outcomes with the actual orbits of the terrestrial planets (angular momentum deficit, mass concentration) and taking into account independent geochemical constraints on the mass accreted by the Earth after the Moon-forming event and on the time scale for the growth of Mars, we conclude that the protoplanetary disc at the beginning of the giant impact phase must have had most of its mass in Mars-sized embryos and only a small fraction of the total disc mass in the planetesimal population. From this, we infer that the Moon-forming event occurred between approximately 60 and approximately 130 Myr after the formation of the first solids and was caused most likely by an object with a mass similar to that of Mars.
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Affiliation(s)
- S A Jacobson
- Laboratoire Lagrange, UNSA, OCA, CNRS, Boulevard de l'Observatoire, BP 4029, 06304 Nice Cedex 4, France Universität Bayreuth, Bayerisches Geoinstitut, Bayreuth 95440 Germany
| | - A Morbidelli
- Laboratoire Lagrange, UNSA, OCA, CNRS, Boulevard de l'Observatoire, BP 4029, 06304 Nice Cedex 4, France
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Chambers J. A chronometer for Earth's age. Nature 2014; 508:51-2. [DOI: 10.1038/508051a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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