Frequent violent collisions of impactors from space punctuated the geological and atmospheric evolution of early Earth. It is generally accepted that the most massive collisions altered the chemistry of Earth’s earliest atmosphere, but the consequences of Archaean collisions for atmospheric oxidation are little understood. Early Archaean (4.0–3.5 billion years ago (Ga)) impact flux models are tightly constrained by lunar cratering and radiometric data. Further, a record of the late Archaean (3.5–2.5 Ga) impact flux is provided by terrestrial impact spherule layers—formed by collisions with bodies ≥10–20 km in diameter—although this record is probably incomplete and significant uncertainties remain. Here we show, on the basis of an assessment of impactor-related spherule records and modelling of the atmospheric effects of these impacts, that current bombardment models underestimate the number of late Archaean spherule layers. These findings suggest that the late Archaean impactor flux was up to a factor of ten higher than previously thought. We find that the delivered impactor mass was an important sink of oxygen, suggesting that early bombardment could have delayed Earth’s atmosphere oxidation. In addition, late Archaean large impacts (≥10 km) probably caused drastic oscillations of atmospheric oxygen, with an average time between consecutive collisions of about 15 Myr. This pattern is consistent with a known episode of atmospheric oxygen oscillation at ~2.5 Ga that is bracketed by large impacts recorded by Bee Gorge (~2.54 Ga) and Dales Gorge (~2.49 Ga) spherule layers.
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Catling, D. C. in Treatise on Geochemistry (eds Holland, H. D. & Turekian, K. K.) 177–195 (Elsevier, 2014); https://doi.org/10.1016/B978-0-08-095975-7.01307-3
Lyons, T. W., Reinhard, C. T. & Planavsky, N. J. The rise of oxygen in Earth‘s early ocean and atmosphere. Nature 506, 307–315 (2014).
Marchi, S. et al. Widespread mixing and burial of Earth’s Hadean crust by asteroid impacts. Nature 511, 578–582 (2014).
Bottke, W. F. & Norman, M. D. The late heavy bombardment. Annu. Rev. Earth Planet. Sci. 45, 619–647 (2017).
Zahnle, K. J., Lupu, R., Catling, D. C. & Wogan, N. Creation and evolution of impact-generated reduced atmospheres of early Earth. Planet. Sci. J. 1, 11 (2020).
Bottke, W. F. et al. An Archaean heavy bombardment from a destabilized extension of the asteroid belt. Nature 485, 78–81 (2012).
Nesvorný, D., Roig, F. & Bottke, W. F. Modeling the historical flux of planetary impactors. Astron. J. 153, 103 (2017).
Morbidelli, A. et al. The timeline of the lunar bombardment: revisited. Icarus 305, 262–276 (2018).
Vokrouhlický, D., Bottke, W. F., Chesley, S. R., Scheeres, D. J. & Statler, T. S. in Asteroids IV (eds Michel, P. et al.) 509–531 (Univ. Arizona Press, 2015).
Johnson, B. C. et al. Spherule layers, crater scaling laws, and the population of ancient terrestrial impactors. Icarus 271, 350–359 (2016).
Nesvorný, D. & Roig, F. Dynamical origin and terrestrial impact flux of large near-Earth asteroids. Astron. J. 155, 42 (2018).
Walker, R. J. Highly siderophile elements in the Earth, Moon and Mars: update and implications for planetary accretion and differentiation. Chem. Erde 69, 101–125 (2009).
Marchi, S., Canup, R. M. & Walker, R. J. Heterogeneous delivery of silicate and metal to the Earth by large planetesimals. Nat. Geosci. 11, 77–81 (2018).
Melosh, H. J. & Vickery, A. M. Melt droplet formation in energetic impact events. Nature 350, 494–497 (1991).
Johnson, B. C. & Melosh, H. J. Impact spherules as a record of an ancient heavy bombardment of Earth. Nature 485, 75–77 (2012).
Glass, B. P. & Simonson, B. M. Distal Impact Ejecta Layers: A Record of Large Impacts in Sedimentary Deposits (Springer, 2013).
Koeberl, C., Schulz, T. & Reimold, W. U. Remnants of early Archean impact deposits on Earth: search for a meteoritic component in the BARB5 and CT3 drill cores (Barberton Greenstone Belt, South Africa). Procedia Eng. 103, 310–317 (2015).
Mohr-Westheide, T. et al. Discovery of extraterrestrial component carrier phases in Archean spherule layers: implications for estimation of Archean bolide sizes. Geology 43, 299–302 (2015).
Drabon, N., Heubeck, C. E. & Lowe, D. R. Evolution of an Archean fan delta and its implications for the initiation of uplift and deformation in the Barberton greenstone belt, South Africa. J. Sediment. Res. 89, 849–874 (2019).
Schulz, T. et al. New constraints on the Paleoarchean meteorite bombardment of the Earth—Geochemistry and Re–Os isotope signatures of the BARB5 ICDP drill core from the Barberton Greenstone Belt, South Africa. Geochim. Cosmochim. Acta 211, 322–340 (2017).
Ozdemir, S. et al. Early Archean spherule layers from the Barberton Greenstone Belt, South Africa: mineralogy and geochemistry of the spherule beds in the CT3 drill core. Meteorit. Planet. Sci. 52, 2586–2631 (2017).
Reimold W. U., Koeberl C., Johnson S. & McDonald I. in Impacts and the Early Earth (eds Gilmour, I. & Koeberl, C.) 117–180 (Springer, 2000).
Ozdemir, S. et al. Meteoritic highly siderophile element and Re–Os isotope signatures of Archean spherule layers from the CT3 drill core, Barberton Greenstone Belt, South Africa. Meteorit. Planet. Sci. 54, 2203–2216 (2019).
Hassler, S. W., Robey, H. F. & Simonson, B. M. Bedforms produced by impact-generated tsunami, ~2.6 Ga Hamersley basin, Western Australia. Sediment. Geol. 135, 283–294 (2000).
Glikson, A. & Allen, D. Iridium anomalies and fractionated siderophile element patterns in impact ejecta, Brockman Iron Formation, Hamersley basin, Western Australia: evidence for a major asteroid impact in simatic crustal regions of the early Proterozoic Earth. Earth Planet. Sci. Lett. 220, 247–264 (2004).
Paquay, F. S., Ravizza, G. E., Dalai, T. K. & Peucker-Ehrenbrink, B. Determining chondritic impactor size from the marine osmium isotope record. Science 320, 214–218 (2008).
Gaillard, F., Scaillet, B. & Arndt, N. T. Atmospheric oxygenation caused by a change in volcanic degassing pressure. Nature 478, 229–232 (2011).
Kump, L. R. & Barley, M. E. Increased subaerial volcanism and the rise of atmospheric oxygen 2.5 billion years ago. Nature 448, 1033–1036 (2007).
Schaefer, L. & Fegley, B. Jr Outgassing of ordinary chondritic material and some of its implications for the chemistry of asteroids, planets, and satellites. Icarus 186, 462–483 (2007).
Hashimoto, G. L., Abe, Y. & Sugita, S. The chemical composition of the early terrestrial atmosphere: formation of a reducing atmosphere from CI-like material. J. Geophys. Res. 112, E05010 (2007).
Claire, M., Catling, D. & Zahnle, K. Biogeochemical modelling of the rise in atmospheric oxygen. Geobiology 4, 239–269 (2006).
Catling, D. C. & Zahnle, K. J. The Archean atmosphere. Sci. Adv. 6, eaax1420 (2020).
Anbar, A. D. et al. A whiff of oxygen before the Great Oxidation Event? Science 317, 1903–1906 (2007).
Kendall, B., Creaser, R. A., Reinhard, C. T., Lyons, T. W. & Anbar, A. D. Transient episodes of mild environmental oxygenation and oxidative continental weathering during the late Archean. Sci. Adv. 1, e1500777 (2015).
Neukum, G. & Ivanov, B. A. in Hazards Due to Comets and Asteroids (eds Gehrels, T. et al.) 359–416 (Univ. Arizona Press, 1994).
Marchi, S., Mottola, S., Cremonese, G., Massironi, M. & Martellato, E. A new chronology for the Moon and Mercury. Astron. J. 137, 4936–4948 (2009).
Robbins, S. J. New crater calibrations for the lunar crater-age chronology. Earth Planet. Sci. Lett. 403, 188–198 (2014).
Morbidelli, A. et al. A sawtooth-like timeline for the first billion years of lunar bombardment. Earth Planet. Sci. Lett. 355–356, 144–151 (2012); https://doi.org/10.1016/j.epsl.2012.07.037
Bottke, W. F. et al. Interpreting the cratering histories of Bennu, Ryugu, and other spacecraft-explored asteroids. Astron. J. 160, 14 (2020).
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).
Harris, A. W. & D’Abramo, G. The population of near-Earth asteroids. Icarus 257, 302–312 (2015).
Holsapple, K. A. & Housen, K. R. A crater and its ejecta: an interpretation of deep impact. Icarus 187, 345–356 (2007).
Melosh, H. J. Impact Cratering: A Geologic Process (Oxford Univ. Press, 1989).
Kirchoff, M. R. et al. Ages of large lunar impact craters and implications for bombardment during the Moon’s middle age. Icarus 225, 325–341 (2013).
Kirchoff, M. R., Marchi, S., Bottke, W. F., Chapman, C. R. & Enke, B. Suggestion that recent (≤3 Ga) flux of kilometer and larger impactors in the Earth–Moon system has not been constant. Icarus 355, 114110 (2021).
Brasser, R., Werner, S. C. & Mojzsis, S. J. Impact bombardment chronology of the terrestrial planets from 4.5 Ga to 3.5 Ga. Icarus 338, 113514 (2020).
Lowe, D. R., Byerly, G. R. & Kyte, F. T. Recently discovered 3.42–3.23 Ga impact layers, Barberton Belt, South Africa: 3.8 Ga detrital zircons, Archean impact history, and tectonic implications. Geology 42, 747–750 (2014).
Lowe, D. R., Byerly, G. R., Asaro, F. & Kyte, F. T. Geological and geochemical record of 3400-million-year-old terrestrial meteorite impacts. Science 245, 959–962 (1989).
Lowe, D. R. et al. Spherule beds 3.47–3.24 billion years old in 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).
Koeberl, C. in Processes on the Early Earth (eds Reimold, W. U. & Gibson, R.) Special Paper 405, Ch. 1, 1–22 (Geological Society of America, 2006).
Hofmann, A., Reimold, W. U. & Koeberl, C. in Processes on the Early Earth (eds Reimold, W. U. & Gibson, R.) 33–56 (Geological Society of America, 2006).
Goncalves de Oliveira, G. J. et al. Petrographic characterization of Archaean impact spherule layers from Fairview Gold Mine, northern Barberton Greenstone Belt, South Africa. J. Afr. Earth Sci. 162, 103718 (2020).
Lowe, D. R. & Byerly, G. R. Reply to comments on ‘Early Archean silicate spherules of probable impact origin, South Africa and Western Australia’. Geology 15, 179–180 (1987).
Kyte, F. T., Zhou, L. & Lowe, D. R. Noble metal abundances in an early Archean impact deposit. Geochim. Cosmochim. Acta 56, 1365–1372 (1992).
Byerly, G. R. & Lowe, D. R. Spinel from Archean impact spherules. Geochim. Cosmochim. Acta 58, 3469–3486 (1994).
Glass, B. P. & Koeberl, C. ODP hole 689B spherules and upper Eocene microtektite and clinopyroxene-bearing spherule strewn fields. Meteorit. Planet. Sci. 34, 197–208 (1999).
Smit, J. The global stratigraphy of the Cretaceous-Tertiary boundary impact ejecta. Annu. Rev. Earth Planet. Sci. 27, 75–113 (1999).
Pierazzo, E., Kring, D. A. & Melosh, H. J. Hydrocode simulation of the Chicxulub impact event and the production of climatically active gases. J. Geophys. Res. 103, 28607–28625 (1998).
Bluth, G. J. S., Doiron, S. D., Schnetzler, C. C., Krueger, A. J. & Walter, L. S. Global tracking of the SO2 clouds from the June, 1991 Mount Pinatubo eruptions. Geophys. Res. Lett. 19, 151–154 (1992).
Melosh, H. J., Schneider, N. M., Zahnle, K. J. & Latham, D. Ignition of global wildfires at the Cretaceous/Tertiary boundary. Nature 343, 251–254 (1990).
Zahnle, K. J. in Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality (eds Sharpton, V. L. & Ward, P. D.) 271–278 (Geological Society of America, 1990).
Parkos, D., Pikus, A., Alexeenko, A. & Melosh, H. Jay HCN production via impact ejecta reentry during the late heavy bombardment. J. Geophys. Res. Planets 123, 892–909 (2018).
Holland, H. D. Volcanic gases, black smokers, and the Great Oxidation Event. Geochim. Cosmochim. Acta 66, 3811–3826 (2002).
Catling, D. C., Zahnle, K. J. & McKay, C. P. Biogenic methane, hydrogen escape, and the irreversible oxidation of early Earth. Science 293, 839–843 (2001).
Byerly, G. R., Lowe, D. R., Wooden, J. L. & Xie, X. An Archean impact layer from the Pilbara and Kaapvaal cratons. Science 297, 1325–1327 (2002).
Drabon, N., Lowe, D. R. & Byerly, G. R. Detrital zircon geochronology of sedimentary rocks of the Paleoarchean Barberton Greenstone Belt, South Africa: no evidence for continental crust. Geology 45, 803–806 (2017).
Kröner, A., Byerly, G. R. & Lowe, D. R. Chronology of early Archaean granite-greenstone evolution in the Barberton Mountain Land, South Africa, based on precise dating by single zircon evaporation. Earth Planet. Sci. Lett. 103, 41–54 (1991).
Byerly, G. R., Kröner, A., Lowe, D. R., Todt, W. & Walsh, M. M. Prolonged magmatism and time constraints for sediment deposition in the early Archean Barberton greenstone belt: evidence from the Upper Onverwacht and Fig Tree groups. Precambrian Res. 78, 125–138 (1996).
Fritz, J. et al. Nondestructive spectroscopic and petrochemical investigations of Paleoarchean spherule layers from the ICDP drill core BARB5, Barberton Mountain Land, South Africa. Meteorit. Planet. Sci. 51, 2441–2458 (2016).
We acknowledge insightful discussions with D. Lowe, B. Black, B. Johnson and R. Fu. T.S. was funded by the German Research Foundation (DFG, SCHU 3061/1-1).
The authors declare no competing interests.
Peer review information Nature Geoscience thanks Roxana Lupu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: James Super.
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Gray curve is the MBA SFD from ref. 40. This SFD was able to generate a NEO SFD in agreement with observations at that time. The orange curve is an update of the MBA SFD—our nominal MBA SFD—that better fit the current NEO SFD (green). The vertical dashed lines indicate reference sizes of 33 m and 5 km (see text for details). For completeness, 1.1 km is also indicated, corresponding to an impactor size that would make a 20 km lunar crater (often used for calibrating bombardment models), for an impactor density of 2.5 g/cm3, 18 km/s impact velocity, 45 deg impact angle (see Methods).
a) Model impactor SFDs (red curves as in Fig. 2b) compared with Monte Carlo retrieval of impactor SFDs from spherule layers for the minimum number of independent layers (Extended Data Table 1). Meaning of symbols and colors as in Fig. 2b. b) Best-fit collisional model. The figure shows the model impactor SFDs (blue curves) for γbest = 10γmax. The green and yellow lines are the impactor SFDs reconstructed from spherule layers (see Fig. 2b), but now impactors sizes are reduced by a factor fbest = 1.5 (see text). The red shaded area indicates the range of impactor SFDs for γmax, as in Fig. 2b.
The calculations assume chemical equilibrium between the total impactor vapor mass and background atmosphere. Here we take a background atmosphere of 0.7 bars N2, 0.3 bars CO2, and 1 ppm O2. The initial impact conditions are taken as 100 bars and 2000 K and used to derive the composition of the impactor vapor in equilibrium with the impacting meteoritic material. We then vary the mass of impactor vapor to atmospheric mass for different impactor diameters. Atmospheric O2 abundances are strongly depleted by 1000 K, indicating that quenching of chemical reactions within the vapor plume should not strongly affect the amount of O2 consumed by the impact.
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Marchi, S., Drabon, N., Schulz, T. et al. Delayed and variable late Archaean atmospheric oxidation due to high collision rates on Earth. Nat. Geosci. 14, 827–831 (2021). https://doi.org/10.1038/s41561-021-00835-9