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Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints

Nature volume 484, pages 359–362 (2012)Cite this article

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Abstract

According to the ‘Faint Young Sun’ paradox, during the late Archaean eon a Sun approximately 20% dimmer warmed the early Earth such that it had liquid water and a clement climate1. Explanations for this phenomenon have invoked a denser atmosphere that provided warmth by nitrogen pressure broadening1 or enhanced greenhouse gas concentrations2. Such solutions are allowed by geochemical studies and numerical investigations that place approximate concentration limits on Archaean atmospheric gases, including methane, carbon dioxide and oxygen2,3,4,5,6,7. But no field data constraining ground-level air density and barometric pressure have been reported, leaving the plausibility of these various hypotheses in doubt. Here we show that raindrop imprints in tuffs of the Ventersdorp Supergroup, South Africa, constrain surface air density 2.7 billion years ago to less than twice modern levels. We interpret the raindrop fossils using experiments in which water droplets of known size fall at terminal velocity into fresh and weathered volcanic ash, thus defining a relationship between imprint size and raindrop impact momentum. Fragmentation following raindrop flattening limits raindrop size to a maximum value independent of air density, whereas raindrop terminal velocity varies as the inverse of the square root of air density. If the Archaean raindrops reached the modern maximum measured size, air density must have been less than 2.3 kg m−3, compared to today’s 1.2 kg m−3, but because such drops rarely occur, air density was more probably below 1.3 kg m−3. The upper estimate for air density renders the pressure broadening explanation1 possible, but it is improbable under the likely lower estimates. Our results also disallow the extreme CO2 levels required for hot Archaean climates8.

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Figure 1: The 2.7-billion-year-old Ventersdorp Supergroup raindrop imprints lithified in tuff at Omdraaivlei, South Africa.
Figure 2: Experimental relationship between raindrop area and dimensionless momentum.
Figure 3: Theoretical predictions of the variation of air density with terminal velocity and dimensionless momentum at the surface.
Figure 4: Atmospheric density given the maximum raindrop diameter that created the largest imprints at Omdraaivlei, South Africa.

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References

  1. Goldblatt, C. et al. Nitrogen-enhanced greenhouse warming on early Earth. Nature Geosci. 2, 891–896 (2009)

    Article  ADS  CAS  Google Scholar 

  2. Kasting, J. Theoretical constraints on oxygen and carbon dioxide concentrations in the Precambrian atmosphere. Precambr. Res. 34, 205–229 (1987)

    Article  ADS  CAS  Google Scholar 

  3. Ohmoto, H., Watanabe, Y. & Kumazawa, K. Evidence from massive siderite beds for a CO2-rich atmosphere before 1.8 billion years ago. Nature 429, 395–399 (2004)

    Article  ADS  CAS  Google Scholar 

  4. Claire, M., Catling, D. & Zahnle, K. Biogeochemical modelling of the rise in atmospheric oxygen. Geobiology 4, 239–269 (2006)

    Article  CAS  Google Scholar 

  5. Domagal-Goldman, S., Kasting, J., Johnston, D. & Farquhar, J. Organic haze, glaciations and multiple sulfur isotopes in the Mid-Archean Era. Earth Planet. Sci. Lett. 269, 29–40 (2008)

    Article  ADS  CAS  Google Scholar 

  6. Haqq-Misra, J., Domagal-Goldman, S., Kasting, P. & Kasting, J. A revised, hazy methane greenhouse for the Archean Earth. Astrobiology 8, 1127–1137 (2008)

    Article  ADS  CAS  Google Scholar 

  7. Driese, S. G. et al. Neoarchean paleoweathering of tonalite and metabasalt: implications for reconstructions of 2.69 Ga early terrestrial ecosystems and paleoatmospheric chemistry. Precambr. Res. 189, 1–17 (2011)

    Article  ADS  CAS  Google Scholar 

  8. Kasting, J. & Howard, M. Atmospheric composition and climate on the early Earth. Phil. Trans. R. Soc. B 361, 1733–1742 (2006)

    Article  CAS  Google Scholar 

  9. Bekker, A. et al. Dating the rise of atmospheric oxygen. Nature 427, 117–120 (2004)

    Article  ADS  CAS  Google Scholar 

  10. Holland, H. D. The oxygenation of the atmosphere and oceans. Phil. Trans. R. Soc. B 361, 903–915 (2006)

    Article  CAS  Google Scholar 

  11. Farquhar, J., Bao, H. & Thiemens, M. Atmospheric influence of Earth’s earliest sulfur cycle. Science 289, 756–758 (2000)

    Article  ADS  CAS  Google Scholar 

  12. Garvin, J. et al. Isotopic evidence for an aerobic nitrogen cycle in the latest Archean. Science 323, 1045–1048 (2009)

    Article  ADS  CAS  Google Scholar 

  13. Knauth, L. & Lowe, D. High Archean climatic temperature inferred from oxygen isotope geochemistry of cherts in the 3.5 Ga Swaziland Supergroup, South Africa. Geol. Soc. Am. Bull. 115, 566–580 (2003)

    Article  ADS  CAS  Google Scholar 

  14. Lyell, C. On fossil rain-marks of the Recent, Triassic, and Carboniferous periods. Q. J. R. Geol. Soc. 7, 238–247 (1851)

    Article  Google Scholar 

  15. Spilhaus, A. Raindrop size, shape and falling speed. J. Atmos. Sci. 5, 108–110 (1948)

    ADS  Google Scholar 

  16. Magono, C. On the shape of water drops falling in stagnant air. J. Meteorol. 11, 77–79 (1954)

    Article  Google Scholar 

  17. Matthews, J. & Mason, B. Electrification produced by the rupture of large water drops in an electric field. Q. J. R. Meteorol. Soc. 90, 275–286 (1964)

    Article  ADS  Google Scholar 

  18. Lorenz, R. The life, death and afterlife of a raindrop on Titan. Planet. Space Sci. 41, 647–655 (1993)

    Article  ADS  CAS  Google Scholar 

  19. Pruppacher, H. R. & Klett, J. D. Microphysics of Clouds and Precipitation (Kluwer Academic, 1997)

    Google Scholar 

  20. Willis, P. & Tattelman, P. Drop-size distribution associated with intense rainfall. J. Appl. Meteorol. 28, 3–15 (1989)

    Article  ADS  Google Scholar 

  21. Dodd, K. On the disintegration of water drops in an air stream. J. Fluid Mech. 9, 175–182 (1960)

    Article  ADS  Google Scholar 

  22. Beard, K. V. Velocity and shape of cloud and precipitation drops aloft. J. Atmos. Sci. 33, 851–864 (1976)

    Article  ADS  Google Scholar 

  23. Clift, R., Grace, J. R. & Weber, M. E. Bubbles, Drops and Particles Ch. 7 (Academic, 1978)

    Google Scholar 

  24. Foote, G. B. & du Toit, P. S. Terminal velocity of raindrops aloft. J. Appl. Meteorol. 8, 249–253 (1969)

    Article  ADS  Google Scholar 

  25. van der Westhuizen, W., Grobler, N., Loock, J. & Tordiffe, E. Raindrop imprints in the Late Archaean-Early Proterozoic Ventersdorp Supergroup, South Africa. Sedim. Geol. 61, 303–309 (1989)

    Article  ADS  Google Scholar 

  26. Reineck, H. & Singh, I. S. Depositional Sedimentary Environments 61 (Springer, 1980)

    Book  Google Scholar 

  27. Huang, C., Bradford, J. M. & Cushman, J. H. A numerical study of raindrop impact phenomena: the elastic deformation case. Soil Sci. Soc. Am. J. 47, 855–861 (1983)

    Article  ADS  Google Scholar 

  28. Easton, R. Stratigraphy of Kilauea Volcano. In Volcanism in Hawaii (eds Decker, R., Wright, T. & Stauffer, P. ) 243–260 (US Government Printing Office, US Geol. Surv. Prof. Pap. 1350, 1987)

    Google Scholar 

  29. Zachos, J., Dickens, G. & Zeeber, R. An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature 451, 279–283 (2008)

    Article  ADS  CAS  Google Scholar 

  30. Hren, M., Tice, M. & Chamberlain, C. Oxygen and hydrogen isotope evidence for a temperate climate 3.42 billion years ago. Nature 462, 205–208 (2009)

    Article  ADS  CAS  Google Scholar 

  31. Knauth, L. Temperature and salinity history of the Precambrian ocean: implications for the course of microbial evolution. Palaeogeogr. Palaeoclimatol. Palaeoecol. 219, 53–69 (2005)

    Article  Google Scholar 

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Acknowledgements

This work was supported by NASA Exobiology/Astrobiology grant NNX08AP56G. We thank W. Van der Westhuizen of the University of the Free State in South Africa, and E. and D. Jackson of Omdraaivlei for their assistance when sampling in the field. We also thank E. Stüeken, A. Chen and K. Huntington at the University of Washington for laboratory assistance, and the staff at Metron Corporation for data acquisition. XRF measurements were performed by the Washington State University Geoanalytical Laboratory. Funding and field logistics for the Iceland fieldwork was supported by the Coordination Action for Research Activities on life in Extreme Environments (CAREX), a project supported by the European Commission Seventh Framework Programme. Funding and field logistics for the Hawaiian fieldwork was supported by the University of Washington Department of Earth and Space Sciences, and its Geoclub. D.C.C. was also supported by NASA Exobiology/Astrobiology grant NNX10AQ90G.

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Author notes

  1. Sanjoy M. Som

    Present address: Present address: Exobiology Branch, NASA Ames Research Center, Moffett Field, California 94035, USA.,

Authors and Affiliations

  1. Department of Earth and Space Sciences and Astrobiology Program, University of Washington, Seattle, 98195-1310, Washington, USA

    Sanjoy M. Som, David C. Catling, Jelte P. Harnmeijer, Peter M. Polivka & Roger Buick

  2. Blue Marble Space Institute of Science, Seattle, 98145, Washington, USA

    Sanjoy M. Som

  3. Sustainable Community Energy Network, Edinburgh Centre for Low Carbon Innovation, Edinburgh EH8 9AA, UK ,

    Jelte P. Harnmeijer

  4. Department of Civil and Environmental Engineering, University of Washington, Seattle, 98195, Washington, USA

    Peter M. Polivka

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Contributions

D.C.C. conceived the research project and established maximum-raindrop-size terminal velocity dependence on air density, R.B. led the field work in South Africa, collected the latex peels and analysed the grain sizes of the Ventersdorp tuff, J.P.H. found additional geographic and stratigraphic occurrences of raindrop imprints while performing field work and helping collect latex peels, P.M.P. collected experimental data and measured the Eyjafjallajökull and Pahala ash grain sizes, and S.M.S. developed the method of dimensionless momentum, collected the volcanic ash from Hawaii and Iceland, analysed the data, and led the experimental work. S.M.S., R.B. and D.C.C. discussed results and prepared the manuscript.

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Correspondence to Sanjoy M. Som.

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The authors declare no competing financial interests.

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Som, S., Catling, D., Harnmeijer, J. et al. Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints. Nature 484, 359–362 (2012). https://doi.org/10.1038/nature10890

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