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An Archaean heavy bombardment from a destabilized extension of the asteroid belt


The barrage of comets and asteroids that produced many young lunar basins (craters over 300 kilometres in diameter) has frequently been called the Late Heavy Bombardment1 (LHB). Many assume the LHB ended about 3.7 to 3.8 billion years (Gyr) ago with the formation of Orientale basin2,3. Evidence for LHB-sized blasts on Earth, however, extend into the Archaean and early Proterozoic eons, in the form of impact spherule beds: globally distributed ejecta layers created by Chicxulub-sized or larger cratering events4. At least seven spherule beds have been found that formed between 3.23 and 3.47 Gyr ago, four between 2.49 and 2.63 Gyr ago, and one between 1.7 and 2.1 Gyr ago5,6,7,8,9. Here we report that the LHB lasted much longer than previously thought, with most late impactors coming from the E belt, an extended and now largely extinct portion of the asteroid belt between 1.7 and 2.1 astronomical units from Earth. This region was destabilized by late giant planet migration10,11,12,13. E-belt survivors now make up the high-inclination Hungaria asteroids14,15. Scaling from the observed Hungaria asteroids, we find that E-belt projectiles made about ten lunar basins between 3.7 and 4.1 Gyr ago. They also produced about 15 terrestrial basins between 2.5 and 3.7 Gyr ago, as well as around 70 and four Chicxulub-sized or larger craters on the Earth and Moon, respectively, between 1.7 and 3.7 Gyr ago. These rates reproduce impact spherule bed and lunar crater constraints.

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Figure 1: Snapshots of the evolution of the E-belt population over time.
Figure 2: Decay curves for our E-belt runs before and after the LHB.
Figure 3: The E-belt impactor flux on the Earth and Moon.


  1. Gomes, R., Levison, H. F., Tsiganis, K. & Morbidelli, A. Origin of the cataclysmic Late Heavy Bombardment period of the terrestrial planets. Nature 435, 466–469 (2005)

    Article  CAS  ADS  Google Scholar 

  2. Wilhelms, D. E. The geologic history of the Moon. US Geol. Surv. Prof. Pap. 1348, 1987 (1987)

    Google Scholar 

  3. Stöffler, D. & Ryder, G. Stratigraphy and isotope ages of lunar geologic units: chronological standard for the inner Solar System. Space Sci. Rev. 96, 9–54 (2001)

    Article  ADS  Google Scholar 

  4. Johnson, B. C. & Melosh, H. J. Impact spherules as a record of ancient heavy bombardment of Earth. Nature (this issue)

  5. Lowe, D. R. et al. Spherule beds 3.47–3.24 billion years old in the Barberton Greenstone belt, South Africa: a record of large meteorite impacts and their influence on early crustal and biological evolution. Astrobiology 3, 7–48 (2003)

    Article  ADS  Google Scholar 

  6. Simonson, B. M. & Glass, B. P. Spherule layers—records of ancient impacts. Annu. Rev. Earth Planet. Sci. 32, 329–361 (2004)

    Article  CAS  ADS  Google Scholar 

  7. Lowe, D. R. & Byerly, G. R. Did LHB end not with a bang but a whimper? The geologic evidence. Lunar Planet. Sci. 41, 2563 (2010)

    ADS  Google Scholar 

  8. Hassler, S. W., Simonson, B. M., Sumner, D. Y. & Bodin, L. Paraburdoo spherule layer (Hamersley Basin, Western Australia): distal ejecta from a fourth large impact near the Archean-Proterozoic boundary. Geology 39, 307–310 (2011)

    Article  ADS  Google Scholar 

  9. Glass, B. P. & Simonson, B. M. Distal impact ejecta layers: spherules and more. Elements 8, 43–48 (2012)

    Article  CAS  Google Scholar 

  10. Tsiganis, K., Gomes, R., Morbidelli, A. & Levison, H. F. Origin of the orbital architecture of the giant planets of the Solar System. Nature 435, 459–461 (2005)

    Article  CAS  ADS  Google Scholar 

  11. Minton, D. A. & Malhotra, R. Secular resonance sweeping of the main asteroid belt during planet migration. Astrophys. J. 732, 53 (2011)

    Article  ADS  Google Scholar 

  12. Morbidelli, A., Brasser, R., Gomes, R., Levison, H. F. & Tsiganis, K. Evidence from the asteroid belt for a violent past evolution of Jupiter’s orbit. Astron. J. 140, 1391–1401 (2010)

    Article  ADS  Google Scholar 

  13. Minton, D. A. & Malhotra, R. Dynamical erosion of the asteroid belt and implications for large impacts in the inner Solar System. Icarus 207, 744–757 (2010)

    Article  ADS  Google Scholar 

  14. Warner, B. D., Harris, A. W., Vokrouhlický, D., Nesvorný, D. & Bottke, W. F. Analysis of the Hungaria asteroid population. Icarus 204, 172–182 (2009)

    Article  ADS  Google Scholar 

  15. Milani, A., Knežević, Z., Novaković, B. & Cellino, A. Dynamics of the Hungaria asteroids. Icarus 207, 769–794 (2010)

    Article  ADS  Google Scholar 

  16. Bottke, W. F. et al. Debiased orbital and absolute magnitude distribution of the near-Earth objects. Icarus 156, 399–433 (2002)

    Article  ADS  Google Scholar 

  17. Brasser, R., Morbidelli, A., Gomes, R., Tsiganis, K. & Levison, H. F. Constructing the secular architecture of the Solar System. II: The terrestrial planets. Astron. Astrophys. 507, 1053–1065 (2009)

    Article  ADS  Google Scholar 

  18. Bottke, W. F. et al. Linking the collisional history of the main asteroid belt to its dynamical excitation and depletion. Icarus 179, 63–94 (2005)

    Article  CAS  ADS  Google Scholar 

  19. Bottke, W. F., Vokrouhlický, D., Rubincam, D. P. & Nesvorný, D. The Yarkovsky and YORP effects: implications for asteroid dynamics. Annu. Rev. Earth Planet. Sci. 34, 157–191 (2006)

    Article  CAS  ADS  Google Scholar 

  20. Strom, R. G., Malhotra, R., Ito, T., Yoshida, F. & Kring, D. A. The origin of planetary impactors in the inner Solar System. Science 309, 1847–1850 (2005)

    Article  CAS  ADS  Google Scholar 

  21. Kring, D. A. & Cohen, B. A. Cataclysmic bombardment throughout the inner solar system 3.9–4.0 Ga. J. Geophys. Res. 107 (E2). 5009 (2002)

  22. Norman, M. D., Duncan, R. A. & Huard, J. J. Imbrium provenance for the Apollo 16 Descartes terrain: argon ages and geochemistry of lunar breccias 67016 and 67455. Geochim. Cosmochim. Acta 74, 763–783 (2010)

    Article  CAS  ADS  Google Scholar 

  23. Bogard, D. D. Impact ages of meteorites: a synthesis. Meteoritics 30, 244–268 (1995)

    Article  CAS  ADS  Google Scholar 

  24. Bogard, D. D. K-Ar ages of meteorites: clues to parent-body thermal histories. Chem. Erde Geochem. 71, 207–226 (2011)

    Article  CAS  ADS  Google Scholar 

  25. Lapen, T. J. et al. A younger age for ALH84001 and its geochemical link to shergottite sources in Mars. Science 328, 347–351 (2010)

    Article  CAS  ADS  Google Scholar 

  26. Bogard, D. D. & Park, J. 39Ar–40Ar dating of the Zagami Martian shergottite and implications for magma origin of excess 40Ar. Meteorit. Planet. Sci. 43, 1113–1126 (2008)

    Article  CAS  ADS  Google Scholar 

  27. Bottke, W. F., Levison, H. F., Nesvorný, D. & Dones, L. Can planetesimals left over from terrestrial planet formation produce the lunar Late Heavy Bombardment? Icarus 190, 203–223 (2007)

    Article  ADS  Google Scholar 

  28. Marchi, S., Bottke, W. B., Kring, D. A. & Morbidelli, A. The onset of the lunar cataclysm as recorded in its ancient crater populations. Earth Planet. Sci. Lett. 325–326, 27–38 (2012)

    Article  ADS  Google Scholar 

  29. Levison, H. F. & Duncan, M. J. The long-term dynamical behavior of short-period comets. Icarus 108, 18–36 (1994)

    Article  ADS  Google Scholar 

  30. Melosh, H. J. Impact Cratering: A Geologic Process Ch. 7 (Oxford University Press, 1989)

    Google Scholar 

  31. McEwen, A. S. et al. Galileo observations of post-Imbrium lunar craters during the first Earth-Moon flyby. J. Geophys. Res. 98, 17,207–17,231 (1993)

    Article  ADS  Google Scholar 

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We thank B. Cohen, C. Chapman, M. Ćuk, L. Dones, D. Kring, S. Marchi, R. Malhotra, M. Norman, E. Scott, J. Taylor and K. Walsh for discussions and comments. We also thank the University of Hawaii for sponsoring W.F.B.’s recent visit, during which these ideas were first developed. This project was supported by NASA’s Lunar Science Institute (Center for Lunar Origin and Evolution, grant number NNA09DB32A). D.V.’s contribution was supported by the Grant Agency of the Czech Republic. A.M. and R.B. thank Germany’s Helmholtz Alliance for providing support through their “Planetary Evolution and Life” programme. B.S.’s contribution was supported by NASA grant NNX08AI29G. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center.

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W.F.B. developed the scenario of the E belt. The numerical runs were constructed by W.F.B. and D.V., with input from D.M., D.N. and H.F.L. Information on the initial conditions of the planets and the nature of late giant planet migration within the Nice model was provided by A.M., R.B., H.F.L. and D.N. Information on the nature of sweeping resonances, how they affected the main belt, and what happened afterwards was provided by D.M., A.M. and R.B. Additional numerical runs not shown here were performed by A.M. and R.B. Information on the nature of impact spherules and their context was provided by B.S. All authors participated in numerous discussions.

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Correspondence to William F. Bottke.

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Bottke, W., Vokrouhlický, D., Minton, D. et al. An Archaean heavy bombardment from a destabilized extension of the asteroid belt. Nature 485, 78–81 (2012).

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