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Continental degassing of 4He by surficial discharge of deep groundwater


Radiogenic 4He is produced by the decay of uranium and thorium in the Earth’s mantle and crust. From here, it is degassed to the atmosphere1,2,3,4,5 and eventually escapes to space1,5,6. Assuming that all of the 4He produced is degassed, about 70% of the total 4He degassed from Earth comes from the continental crust2,3,4,5,7. However, the outgoing flux of crustal 4He has not been directly measured at the Earth’s surface2 and the migration pathways are poorly understood2,3,4,7,8. Here we present measurements of helium isotopes and the long-lived cosmogenic radio-isotope 81Kr in the deep, continental-scale Guarani aquifer in Brazil and show that crustal 4He reaches the atmosphere primarily by the surficial discharge of deep groundwater. We estimate that 4He in Guarani groundwater discharge accounts for about 20% of the assumed global flux from continental crust, and that other large aquifers may account for about 33%. Old groundwater ages suggest that 4He in the Guarani aquifer accumulates over half- to one-million-year timescales. We conclude that 4He degassing from the continents is regulated by groundwater discharge, rather than episodic tectonic events, and suggest that the assumed steady state between crustal production and degassing of 4He, and its resulting atmospheric residence time, should be re-examined.

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Figure 1: Sampling locations, 4He concentrations and 81Kr ages for groundwater samples from the Guarani aquifer.
Figure 2: Guarani groundwater ages estimated by 14C,81Kr and 4He.
Figure 3: Observed and modelled 4He concentrations in Guarani groundwater samples.


  1. 1

    Turekian, K. K. The terrestrial economy of helium and argon. Geochim. Cosmochim. Acta 17, 37–43 (1959).

    Article  Google Scholar 

  2. 2

    Oxburgh, E. R. & O’Nions, R. K. Helium loss, tectonics, and the terrestrial heat budget. Science 237, 1583–1588 (1987).

    Article  Google Scholar 

  3. 3

    O’Nions, R. K. & Oxburgh, E. R. Heat and helium in the earth. Nature 306, 429–431 (1983).

    Article  Google Scholar 

  4. 4

    Ballentine, C. J. & Burnard, P. G. Production, release and transport of noble gases in the continental crust. Rev. Mineral. Geochem. 47, 481–538 (2002).

    Article  Google Scholar 

  5. 5

    Mamyrin, B. A. & Tolstikhin, I. N. Helium Isotopes in Nature (Elsevier, 1984).

    Google Scholar 

  6. 6

    Kockarts, G. Helium in the terrestrial atmosphere. Space Sci. Rev. 14, 723–757 (1973).

    Article  Google Scholar 

  7. 7

    Torgersen, T. Terrestrial helium degassing fluxes and the atmospheric helium budget: Implications with respect to the degassing processes of continental crust. Chem. Geol. 79, 1–14 (1989).

    Google Scholar 

  8. 8

    Ballentine, C. J., Burgess, R. & Marty, B. Tracing fluid origin, transport and interaction in the crust. Rev. Mineral. Geochem. 47, 539–614 (2002).

    Article  Google Scholar 

  9. 9

    Neretnieks, I. Some aspects of release and transport of gases in deep granitic rocks: Possible implications for nuclear waste repositories. Hydrogeol. J. 21, 1701–1716 (2013).

    Article  Google Scholar 

  10. 10

    Newton, R. & Round, G. F. The diffusion of helium through sedimentary rocks. Geochim. Cosmochim. Acta 22, 106–132 (1961).

    Article  Google Scholar 

  11. 11

    Savchenko, V. P. The problems of geochemistry of helium [in Russian]. Nat. Gases 9, 53–197 (1935).

    Google Scholar 

  12. 12

    Andrews, J. N. The isotopic composition of radiogenic helium and its use to study groundwater movement in confined aquifers. Chem. Geol. 49, 339–351 (1985).

    Article  Google Scholar 

  13. 13

    Castro, M. C., Goblet, P., Ledoux, E., Violette, S. & Marsily, G. d. Noble gases as natural tracers of water circulation in the Paris Basin 2. Calibration of a groundwater flow model using noble gas isotope data. Wat. Resour. Res. 34, 2467–2483 (1998).

    Article  Google Scholar 

  14. 14

    Bethke, C. M., Torgersen, T. & Park, J. The ‘age’ of very old groundwater: Insights from reactive transport models. J. Geochem. Explor. 69–70, 1–4 (2000).

    Article  Google Scholar 

  15. 15

    Martel, D. J., Deak, J., Dövenyi, P., Horvath, F. & O’Nions, R. K. Leakage of helium from the Pannonian Basin. Nature 342, 908–912 (1989).

    Article  Google Scholar 

  16. 16

    Aeschbach-Hertig, W., Stute, M., Clark, J. F., Reuter, R. F. & Schlosser, P. A paleotemperature record derived from dissolved noble gases in groundwater of the Aquia aquifer (Maryland, USA). Geochim. Cosmochim. Acta 66, 797–817 (2002).

    Article  Google Scholar 

  17. 17

    Plummer, L. N. et al. Old groundwater in parts of the upper Patapsco aquifer, Atlantic Coastal Plain, Maryland, USA: Evidence from radiocarbon, chlorine-36 and helium-4. Hydrogeol. J. 20, 1269–1294 (2012).

    Article  Google Scholar 

  18. 18

    Rebouças, A. C. Recursos Hídricos Subterrâneos da Bacia do Paraná [Underground Water Resources of the Paraná Basin] PhD thesis, Univ. São Paulo (1976)

  19. 19

    Araújo, L. M., França, B. & Potter, P. E. Hydrogeology of the Mercosul aquifer system in the Paraná and Chaco-Paraná Basins, South America, and comparison with the Navajo-Nugget aquifer system, USA. Hydrogeol. J. 7, 317–336 (1999).

    Article  Google Scholar 

  20. 20

    Margat, J. & van der Gun, J. Groundwater Around the World (CRC Press, 2013).

    Book  Google Scholar 

  21. 21

    Torgersen, T. & Ivey, G. N. Helium accumulation in groundwater. II: A model for the accumulation of the crustal 4He degassing flux. Geochim. Cosmochim. Acta 49, 2445–2452 (1985).

    Article  Google Scholar 

  22. 22

    Hitchon, B. Geochemical studies of natural gas Part III. Inert gases in Western Canadian natural gases. J. Can. Petrol. Technol. 2, 165–174 (1963).

    Article  Google Scholar 

  23. 23

    Golubev, V. S., Yeremeyev, A. N. & Yanitskiy, I. N. Analysis of some models of helium migration in the lithosphere. Geochem. Int. 11, 734–742 (1975).

    Google Scholar 

  24. 24

    Lowenstern, J. B., Evans, W. C., Bergfeld, D. & Hunt, A. G. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone. Nature 506, 355–358 (2014).

    Article  Google Scholar 

  25. 25

    Johnston, R. H. Hydrologic Budgets of Regional Aquifer Systems of the United States for Predevelopment and Development Conditions Professional paper 1425 (US Geological Survey, 1999).

    Google Scholar 

  26. 26

    Heaton, T. H. E. Rates and sources of 4He accumulation in groundwater. Hydrol. Sci. J. 29, 29–47 (1984).

    Article  Google Scholar 

  27. 27

    Kulongoski, J. T., Hilton, D. R. & Selaolo, E. T. Climate variability in the Botswana Kalahari from the late Pleistocene to the present day. Geophys. Res. Lett. 31, L10204 (2004).

    Article  Google Scholar 

  28. 28

    Hunt, A. G., Labert, R. B. & Fahlquist, L. Sources of Groundwater Based on Helium Analyses in and near the Freshwater/Saline-Water Transition Zone of the San Antonio Segment of the Edwards Aquifer, South-Central Texas, 2002–03 Sci. Inv. Report 2010-5030 (US Geological Survey, 2010).

  29. 29

    Aggarwal, P. K., Araguas-Araguas, L., Choudhry, M., van Duren, M. & Froehlich, K. Lower groundwater 14C age by atmospheric CO2 uptake during sampling and analysis. Ground Water 52, 20–24 (2014).

    Article  Google Scholar 

  30. 30

    Lu, Z-T. et al. Tracer applications of noble gas radionuclides in the geosciences. Earth Sci. Rev. 138, 196–214 (2014).

    Article  Google Scholar 

  31. 31

    Plummer, L. N. & Glynn, P. D. Isotope Methods for Dating Old Groundwater 125–152 (IAEA, 2013).

    Google Scholar 

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W.J., Z-T.L., P.M. and the Laboratory for Radiokrypton Dating at Argonne are supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357. Development of the ATTA-3 instrument was supported in part by NSF EAR-0651161. C. Sambandam, L-F. Han, D. Hillegonds, P. Klaus, S. Terzer and E. Izweski of IAEA assisted in noble gas analysis or with graphic illustrations.

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P.K.A. initiated the project and conceived of the proposed mechanism for crustal degassing; P.K.A., N.C.S., H.K.C. and D.G. designed and conducted the sampling campaign with assistance from L.J.A-A. and W.J.; R.Y. and R.P. purified krypton, W.J., Z-T.L. and P.M. measured krypton isotopes, T.M. conducted noble gas analysis and model calculations; P.K.A. and T.M. wrote the paper with assistance from L.J.A-A.; H.K.C., D.G., N.C.S. and T.T. contributed to data evaluation and presentation. All authors reviewed and commented on the manuscript.

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Correspondence to Pradeep K. Aggarwal.

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The authors declare no competing financial interests.

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Aggarwal, P., Matsumoto, T., Sturchio, N. et al. Continental degassing of 4He by surficial discharge of deep groundwater. Nature Geosci 8, 35–39 (2015).

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