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Capture of nebular gases during Earth’s accretion is preserved in deep-mantle neon

Nature (2018) | Download Citation

Abstract

Evidence for the capture of nebular gases by planetary interiors would place important constraints on models of planet formation. These constraints include accretion timescales, thermal evolution, volatile compositions and planetary redox states1,2,3,4,5,6,7. Retention of nebular gases by planetary interiors also constrains the dynamics of outgassing and volatile loss associated with the assembly and ensuing evolution of terrestrial planets. But evidence for such gases in Earth’s interior remains controversial8,9,10,11,12,13,14. The ratio of the two primordial neon isotopes, 20Ne/22Ne, is significantly different for the three potential sources of Earth’s volatiles: nebular gas15, solar-wind-irradiated material16 and CI chondrites17. Therefore, the 20Ne/22Ne ratio is a powerful tool for assessing the source of volatiles in Earth’s interior. Here we present neon isotope measurements from deep mantle plumes that reveal 20Ne/22Ne ratios of up to 13.03 ± 0.04 (2 standard deviations). These ratios are demonstrably higher than those for solar-wind-irradiated material and CI chondrites, requiring the presence of nebular neon in the deep mantle. Furthermore, we determine a 20Ne/22Ne ratio for the primordial plume mantle of 13.23 ± 0.22 (2 standard deviations), which is indistinguishable from the nebular ratio, providing robust evidence for a reservoir of nebular gas preserved in the deep mantle today. The acquisition of nebular gases requires planetary embryos to grow to sufficiently large mass before the dissipation of the protoplanetary disk. Our observations also indicate distinct 20Ne/22Ne ratios between deep mantle plumes and mid-ocean-ridge basalts, which is best explained by addition of a chondritic component to the shallower mantle during the main phase of Earth’s accretion and by subsequent recycling of seawater-derived neon in plate tectonic processes.

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Data availability

The main data supporting the findings of this study are available within the article, its Extended Data and Supplementary Table 1, as well as in the EarthChem database (https://doi.org/10.1594/IEDA/111217).

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References

  1. 1.

    Mizuno, H., Nakazawa, K. & Hayashi, C. Dissolution of the primordial rare gases into the molten Earth’s material. Earth Planet. Sci. Lett. 50, 202–210 (1980).

  2. 2.

    Sasaki, S. & Nakazawa, K. Did a primary solar-type atmosphere exist around the proto-Earth? Icarus 85, 21–42 (1990).

  3. 3.

    Harper, C. L. Jr & Jacobsen, S. B. Noble gases and Earth’s accretion. Science 273, 1814–1818 (1996).

  4. 4.

    Matsui, T. & Abe, Y. Evolution of an impact-induced atmosphere and magma ocean on the accreting Earth. Nature 319, 303–305 (1986).

  5. 5.

    Kuramoto, K. & Matsui, T. Partitioning of H and C between the mantle and core during the core formation in the Earth: its implications for the atmospheric evolution and redox state of early mantle. J. Geophys. Res. 101, 14909 (1996).

  6. 6.

    Hirschmann, M. M., Withers, A. C., Ardia, P. & Foley, N. T. Solubility of molecular hydrogen in silicate melts and consequences for volatile evolution of terrestrial planets. Earth Planet. Sci. Lett. 345–348, 38–48 (2012).

  7. 7.

    Hirschmann, M. M. Magma ocean influence on early atmosphere mass and composition. Earth Planet. Sci. Lett. 341, 48–57 (2012).

  8. 8.

    Péron, S., Moreira, M., Putlitz, B. & Kurz, M. D. Solar wind implantation supplied light volatiles during the first stage of Earth accretion. Geochem. Perspect. Lett. 3, 151–159 (2017).

  9. 9.

    Moreira, M. & Charnoz, S. The origin of the neon isotopes in chondrites and on Earth. Earth Planet. Sci. Lett. 433, 249–256 (2016).

  10. 10.

    Ballentine, C. J., Marty, B., Lollar, B. S. & Cassidy, M. Neon isotopes constrain convection and volatile origin in the Earth’s mantle. Nature 433, 33–38 (2005).

  11. 11.

    Trieloff, M., Kunz, J., Clague, D. A., Harrison, D. & Allègre, C. J. The nature of pristine noble gases in mantle plumes. Science 288, 1036–1038 (2000).

  12. 12.

    Marty, B. The origins and concentrations of water, carbon, nitrogen and noble gases on Earth. Earth Planet. Sci. Lett. 313–314, 56–66 (2012).

  13. 13.

    Yokochi, R. & Marty, B. A determination of the neon isotopic composition of the deep mantle. Earth Planet. Sci. Lett. 225, 77–88 (2004).

  14. 14.

    Mukhopadhyay, S. Early differentiation and volatile accretion recorded in deep-mantle neon and xenon. Nature 486, 101–104 (2012).

  15. 15.

    Heber, V. S. et al. Isotopic mass fractionation of solar wind: evidence from fast and slow solar wind collected by the Genesis mission. Astrophys. J. 759, 121 (2012).

  16. 16.

    Black, D. C. On the origins of trapped helium, neon and argon isotopic variations in meteorites—II. Carbonaceous meteorites. Geochim. Cosmochim. Acta 36, 377–394 (1972).

  17. 17.

    Mazor, E., Heymann, D. & Anders, E. Noble gases in carbonaceous chondrites. Geochim. Cosmochim. Acta 34, 781–824 (1970).

  18. 18.

    Halliday, A. N. The origins of volatiles in the terrestrial planets. Geochim. Cosmochim. Acta 105, 146–171 (2013).

  19. 19.

    Holland, G. & Ballentine, C. J. Seawater subduction controls the heavy noble gas composition of the mantle. Nature 441, 186–191 (2006).

  20. 20.

    Péron, S. et al. Neon isotopic composition of the mantle constrained by single vesicle analyses. Earth Planet. Sci. Lett. 449, 145–154 (2016).

  21. 21.

    Kurz, M. D. et al. Correlated helium, neon, and melt production on the super-fast spreading East Pacific Rise near 17° S. Earth Planet. Sci. Lett. 232, 125–142 (2005).

  22. 22.

    Sarda, P., Moreira, M., Staudacher, T., Schilling, J.-G. & Allègre, C. J. Rare gas systematics on the southernmost Mid-Atlantic Ridge: constraints on the lower mantle and the Dupal source. J. Geophys. Res. 105, 5973–5996 (2000).

  23. 23.

    Kendrick, M. A., Scambelluri, M., Honda, M. & Phillips, D. High abundances of noble gas and chlorine delivered to the mantle by serpentinite subduction. Nat. Geosci. 4, 807 (2011).

  24. 24.

    Douglass, J., Schilling, J. G. & Fontignie, D. Plume-ridge interactions of the Discovery and Shona mantle plumes with the southern Mid-Atlantic Ridge (40°–55° S). J. Geophys. Res. Solid Earth 104, 2941–2962 (1999).

  25. 25.

    Moreira, M. Noble gas constraints on the origin and evolution of Earth’s volatiles. Geochem. Perspect. 2, 229–403 (2013).

  26. 26.

    Caracausi, A., Avice, G., Burnard, P. G., Füri, E. & Marty, B. Chondritic xenon in the Earth’s mantle. Nature 533, 82–85 (2016).

  27. 27.

    Clesi, V. et al. Low hydrogen contents in the cores of terrestrial planets. Sci. Adv. 4, e1701876 (2018).

  28. 28.

    Mamajek, E. E., Usuda, T., Tamura, M. & Ishii, M. Initial conditions of planet formation: lifetimes of primordial disks. AIP Conf. Proc. 1158, 3–10 (2009).

  29. 29.

    Dauphas, N. & Pourmand, A. Hf–W–Th evidence for rapid growth of Mars and its status as a planetary embryo. Nature 473, 489–492 (2011).

  30. 30.

    Rubie, D. C. et al. Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion of water. Icarus 248, 89–108 (2015).

  31. 31.

    Andrews, S. M. et al. Ringed substructure and a gap at 1 au in the nearest protoplanetary disk. Astrophys. J. Lett. 820, L40 (2016).

  32. 32.

    Gayer, E., Mukhopadhyay, S. & Meade, B. J. Spatial variability of erosion rates inferred from the frequency distribution of cosmogenic 3He in olivines from Hawaiian river sediments. Earth Planet. Sci. Lett. 266, 303–315 (2008).

  33. 33.

    Taylor, J. An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements 2nd edn (University Science Books, Sausalito, 1997).

  34. 34.

    Courtillot, V., Davaille, A., Besse, J. & Stock, J. Three distinct types of hotspots in the Earth’s mantle. Earth Planet. Sci. Lett. 205, 295–308 (2003).

  35. 35.

    Gale, A., Dalton, C. A., Langmuir, C. H., Su, Y. & Schilling, J. G. The mean composition of ocean ridge basalts. Geochem. Geophys. Geosyst. 14, 489–518 (2013).

  36. 36.

    Hanyu, T. et al. Noble gas study of the Reunion hotspot: evidence for distinct less-degassed mantle sources. Earth Planet. Sci. Lett. 193, 83–98 (2001).

  37. 37.

    Honda, M. & Woodhead, J. D. A primordial solar-neon enriched component in the source of EM-I-type ocean island basalts from the Pitcairn Seamounts, Polynesia. Earth Planet. Sci. Lett. 236, 597–612 (2005).

  38. 38.

    Moreira, M., Kunz, J. & Allegre, C. Rare gas systematics in popping rock: isotopic and elemental compositions in the upper mantle. Science 279, 1178–1181 (1998).

  39. 39.

    Moreira, M. & Allègre, C. J. Rare gas systematics on Mid Atlantic Ridge (37–40° N). Earth Planet. Sci. Lett. 198, 401–416 (2002).

  40. 40.

    Parai, R., Mukhopadhyay, S. & Lassiter, J. C. New constraints on the HIMU mantle from neon and helium isotopic compositions of basalts from the Cook–Austral Islands. Earth Planet. Sci. Lett. 277, 253–261 (2009).

  41. 41.

    Parai, R., Mukhopadhyay, S. & Standish, J. J. Heterogeneous upper mantle Ne, Ar and Xe isotopic compositions and a possible Dupal noble gas signature recorded in basalts from the Southwest Indian Ridge. Earth Planet. Sci. Lett. 359, 227–239 (2012).

  42. 42.

    Pető, M. K., Mukhopadhyay, S. & Kelley, K. A. Heterogeneities from the first 100 million years recorded in deep mantle noble gases from the Northern Lau Back-arc Basin. Earth Planet. Sci. Lett. 369–370, 13–23 (2013).

  43. 43.

    Pető, M. K. Application of Noble Gas Isotopic Systems to Identify Mantle Heterogeneities. PhD thesis, Harvard Univ. (2014).

  44. 44.

    Stroncik, N. A. & Niedermann, S. He, Ne and Ar isotope signatures of mid-ocean ridge basalts and their implications for upper mantle structure: a case study from the Mid-Atlantic Ridge at 4–12° S. Geochim. Cosmochim. Acta 183, 94–105 (2016).

  45. 45.

    Tucker, J. M., Mukhopadhyay, S. & Schilling, J. G. The heavy noble gas composition of the depleted MORB mantle (DMM) and its implications for the preservation of heterogeneities in the mantle. Earth Planet. Sci. Lett. 355–356, 244–254 (2012).

  46. 46.

    Valbracht, P. J., Staudacher, T., Malahoff, A. & Allègre, C. J. Noble gas systematics of deep rift zone glasses from Loihi Seamount, Hawaii. Earth Planet. Sci. Lett. 150, 399–411 (1997).

  47. 47.

    Moreira, M., Staudacher, T., Sarda, P., Schilling, J. G. & Allègre, C. J. A primitive plume neon component in MORB: the Shona ridge-anomaly, South Atlantic (51–52° S). Earth Planet. Sci. Lett. 133, 367–377 (1995).

  48. 48.

    Moreira, M., Valbracht, P. J., Staudacher, T. & Allègre, C. J. Rare gas systematics in Red Sea Ridge basalts. Geophys. Res. Lett. 23, 2453–2456 (1996).

  49. 49.

    Raquin, A. & Moreira, M. Atmospheric 38Ar/36Ar in the mantle: implications for the nature of the terrestrial parent bodies. Earth Planet. Sci. Lett. 287, 551–558 (2009).

  50. 50.

    Moreira, M. et al. Rare gas systematics on Lucky Strike basalts (37° N, North Atlantic): evidence for efficient homogenization in a long-lived magma chamber system? Geophys. Res. Lett. 38, L08304 (2011).

  51. 51.

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

  52. 52.

    Leya, I. & Wieler, R. Nucleogenic production of Ne isotopes in Earth’s crust and upper mantle induced by alpha particles from the decay of U and Th. J. Geophys. Res. Solid Earth 104, 15439–15450 (1999).

  53. 53.

    Yatsevich, I. & Honda, M. Production of nucleogenic neon in the Earth from natural radioactive decay. J. Geophys. Res. Solid Earth 102, 10291–10298 (1997).

  54. 54.

    Hünemohr, H. Edelgase in U- und Th-reichen Mineralen und die Bestimmung der 21Ne-Dicktarget-Ausbeute der 18O(α,n)21Ne-Kernreaktion im Bereich 4.0–8.8 MeV. PhD thesis, Johannes-Gutenberg Univ. (1989).

  55. 55.

    Kyser, T. K. & Rison, W. Systematics of rare gas isotopes in basic lavas and ultramafic xenoliths. J. Geophys. Res. Solid Earth 87, 5611–5630 (1982).

  56. 56.

    Kennedy, B. M., Hiyagon, H. & Reynolds, J. H. Crustal neon: a striking uniformity. Earth Planet. Sci. Lett. 98, 277–286 (1990).

  57. 57.

    Ballentine, C. J. Resolving the mantle He/Ne and crustal 21Ne/22Ne in well gases. Earth Planet. Sci. Lett. 152, 233–249 (1997).

  58. 58.

    Meshik, A., Hohenberg, C., Pravdivtseva, O. & Burnett, D. Heavy noble gases in solar wind delivered by Genesis mission. Geochim. Cosmochim. Acta 127, 326–347 (2014).

  59. 59.

    Jenkins, W. J. et al. The deep distributions of helium isotopes, radiocarbon, and noble gases along the US GEOTRACES East Pacific Zonal Transect (GP16). Mar. Chem. 201, 167–182 (2018).

  60. 60.

    Kendrick, M. A. et al. Subduction zone fluxes of halogens and noble gases in seafloor and forearc serpentinites. Earth Planet. Sci. Lett. 365, 86–96 (2013).

  61. 61.

    Kendrick, M. A., Scambelluri, M., Hermann, J. & Padron-Navarta, J. A. Halogens and noble gases in serpentinites and secondary peridotites: implications for seawater subduction and the origin of mantle neon. Geochim. Cosmochim. Acta 235, 285–304 (2018).

  62. 62.

    Beyersdorf-Kuis, U., Ott, U. & Trieloff, M. Early cosmic ray irradiation of chondrules and prolonged accretion of primitive meteorites. Earth Planet. Sci. Lett. 423, 13–23 (2015).

  63. 63.

    Das, J. P. & Murty, S. V. S. Cosmogenic and trapped noble gases in individual chondrules: clues to chondrule formation. Meteorit. Planet. Sci. 44, 1797–1818 (2009).

  64. 64.

    Das, J. P., Goswami, J. N., Pravdivtseva, O. V., Meshik, A. P. & Hohenberg, C. M. Cosmogenic neon in grains separated from individual chondrules: evidence of precompaction exposure in chondrules. Meteorit. Planet. Sci. 47, 1869–1883 (2012).

  65. 65.

    Eugster, O., Lorenzetti, S., Krähenbühl, U. & Marti, K. Comparison of cosmic-ray exposure ages and trapped noble gases in chondrule and matrix samples of ordinary, enstatite, and carbonaceous chondrites. Meteorit. Planet. Sci. 42, 1351–1371 (2007).

  66. 66.

    Nakamura, T., Nagao, K., Metzler, K. & Takaoka, N. Heterogeneous distribution of solar and cosmogenic noble gases in CM chondrites and implications for the formation of CM parent bodies. Geochim. Cosmochim. Acta 63, 257–273 (1999).

  67. 67.

    Ott, U., Wieler, R. & Huber, L. Comment on “Cosmogenic neon in grains separated from individual chondrules: evidence of precompaction exposure in chondrules” by J. P. Das, J. N. Goswami, O. V. Pravdivtseva, A. P. Meshik, and C. M. Hohenberg. Meteorit. Planet. Sci. 48, 1524–1528 (2013).

  68. 68.

    Polnau, E., Eugster, O., Burger, M., Krähenbühl, U. & Marti, K. Precompaction exposure of chondrules and implications. Geochim. Cosmochim. Acta 65, 1849–1866 (2001).

  69. 69.

    Riebe, M. E. et al. Cosmogenic He and Ne in chondrules from clastic matrix and a lithic clast of Murchison: no pre-irradiation by the early sun. Geochim. Cosmochim. Acta 213, 618–634 (2017).

  70. 70.

    Roth, A. S. G., Baur, H., Heber, V. S., Reusser, E. & Wieler, R. Cosmogenic helium and neon in individual chondrules from Allende and Murchison: implications for the precompaction exposure history of chondrules. Meteorit. Planet. Sci. 46, 989–1006 (2011).

  71. 71.

    Roth, A. S., Metzler, K., Baumgartner, L. P. & Leya, I. Cosmic-ray exposure ages of chondrules. Meteorit. Planet. Sci. 51, 1256–1267 (2016).

  72. 72.

    Roth, A. S., Metzler, K., Baumgartner, L. P., Hofmann, B. A. & Leya, I. Protracted storage of CR chondrules in a region of the disk transparent to galactic cosmic rays. Meteorit. Planet. Sci. 52, 2166–2177 (2017).

  73. 73.

    Okazaki, R., Takaoka, N., Nagao, K. & Nakamura, T. Noble gases in enstatite chondrites released by stepped crushing and heating. Meteorit. Planet. Sci. 45, 339–360 (2010).

  74. 74.

    Wacker, J. F. & Marti, K. Noble gas components in clasts and separates of the Abee meteorite. Earth Planet. Sci. Lett. 62, 147–158 (1983).

  75. 75.

    Wieler, R., Baur, H., Graf, T. & Signer, P. He, Ne, and Ar in Antarctic meteorites: solar noble gases in an enstatite chondrite. In Proc. Lunar and Planetary Science Conference Vol. 16, 903–904 (AGU, Washington DC, 1985).

  76. 76.

    Lorenzetti, S. et al. History and origin of aubrites. Geochim. Cosmochim. Acta 67, 557–571 (2003).

  77. 77.

    Miura, Y. N., Hidaka, H., Nishiizumi, K. & Kusakabe, M. Noble gas and oxygen isotope studies of aubrites: a clue to origin and histories. Geochim. Cosmochim. Acta 71, 251–270 (2007).

  78. 78.

    Rayleigh, L. L. Theoretical considerations respecting the separation of gases by diffusion and similar processes. Lond. Edinb. Dublin Phil. Mag. J. Sci. 42, 493–498 (1896).

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Acknowledgements

This work is supported by an NSF EAR Postdoctoral Fellowship and NSF grant EAR-1250419. Discovery samples were obtained during the cruise EW9309 of RV Maurice Ewing (in November–December 1993) and provided by the Marine Geological Samples Laboratory, of the Graduate School of Oceanography, University of Rhode Island.

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Nature thanks D. Graham and the other anonymous reviewer(s) for their contribution to the peer review of this work.

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Affiliations

  1. Department of Earth and Planetary Sciences, University of California-Davis, Davis, CA, USA

    • Curtis D. Williams
    •  & Sujoy Mukhopadhyay

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Contributions

Both authors contributed to the design of the study, analyses and data processing. C.D.W. wrote the manuscript with input from S.M.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Curtis D. Williams.

Extended data figures and tables

  1. Extended Data Fig. 1 Lack of mass-dependent isotope fractionation in the step-crushing neon data.

    Péron et al.8 suggested that using the highest measured 20Ne/22Ne ratios for characterizing the plume mantle is inappropriate because mass-dependent isotope fractionation may occur during bubble formation8. In this scenario, mass-dependent fractionation during bubble formation would lead to 20Ne/22Ne ratios scattering about the ‘true’ mean value, with some bubbles characterized by relatively high 20Ne/22Ne ratios while other bubbles displayed relatively low 20Ne/22Ne ratios. This hypothesis can be tested by measuring 4He/3He and 38Ar/36Ar ratios during the same step-crushes as the neon isotopes as illustrated here. a, b, The measured neon isotopic compositions of individual step-crushes plotted against those of helium (a) and argon (b) along with predicted trajectories of mass-dependent isotope fractionation during bubble formation obtained by applying a Rayleigh fractionation model78. Here, the parental melt is assumed to have an initial 20Ne/22Ne ratio of 12.65 ± 0.08, similar to the value of ref. 8. Initial helium and argon isotopic compositions are from the mean values determined for sample EW9309_5D in this study (Supplementary Table 1). The curves show the trajectory of the melts during degassing, the evolution of an instantaneously lost vapour phase (bubbles; short-dashed line) and the cumulative evolution of the vapour phase (bubbles; solid line). Plotted along with these curves are the individual step-crushes (circles) from this study (sample EW9309_5D) with their associated 2σ uncertainties (error bars). Note that the 4He/3He ratios were measured only on one aliquot of EW9309_5D. The helium–neon–argon isotopic compositions measured in the individual step-crushes do not follow the predicted Rayleigh fractionation trends. Rather, the data cloud is at a high angle to the predicted isotope fractionation trend. For example, for our highest measured 20Ne/22Ne of 13.03 ± 0.04 (2σ) to be a result of mass fractionation, the measured 38Ar/36Ar should be 0.1847 (b). However, the measured 38Ar/36Ar of 0.1885 ± 0.0014 (2σ) is identical to the atmospheric value and similar to other determinations of 38Ar/36Ar ratios in plumes and MORBs. Given this, we conclude that mass-dependent isotope fractionation during bubble formation is not responsible for generating the highest 20Ne/22Ne ratios determined in these studies.

  2. Extended Data Fig. 2 Frequency functions for non-plume-influenced MORBs MORBs and plume-influenced basalts.

    Histograms and kernel density estimates were constructed from the maximum measured neon isotopic composition (20Ne/22Nemax) of globally distributed, mantle-derived samples from non-plume-influenced MORBs (solid curve) and plume-influenced basalts (dashed curve), similar to Fig. 2. Kernel density estimates were calculated using the Matlab Curve Fitting Toolbox with bandwidths of 0.16 and 0.12 for non-plume-influenced MORBs and plume-influenced materials, respectively. The kernel density estimator results in slightly broader distributions than observed in Fig. 2 but does not change the main conclusions that there is a clear difference between the maximum measured 20Ne/22Ne ratios for non-plume-influenced MORBs and for plume-influenced basalts, with MORBs displaying a sharp cut-off at a 20Ne/22Ne ratio of 12.5.

  3. Extended Data Fig. 3 Collection depths of non-plume-influenced MORB samples and plume-influenced basalts.

    Depths are in metres. MORB samples (squares) highlighted in this study all erupted from depths between 2,000 and 5,000 m below sea level, and plume-influenced basalts (circles) on average erupted at comparable or shallower depths. For comparable eruption depths, plume-influenced basalts show higher 20Ne/22Ne ratios than non-plume-influenced MORBs. Moreover, if atmospheric contamination played a role in generating the difference between these two populations, plume-influenced basalts should have lower 20Ne/22Ne ratios, given their shallower eruption depth in the sample suite. However, such a relationship is not observed. Therefore, we conclude that different eruption depths are not responsible for the two distinct modes observed for non-plume-influenced MORBs and for plume-influenced basalts shown in Fig. 2. We note that the depth of eruption for Iceland sample DICE 10 is unknown, as it was erupted subglacially. Here, we have assigned a value of zero metres below sea-level to the DICE 10 samples, but deeper eruption depths will not change the results of this study. Data sources are reported in Extended Data Table 1.

  4. Extended Data Fig. 4 Long-term external reproducibility of bracketing standards.

    a, Mass discrimination of the 20Ne/22Ne ratio as a function of the 20Ne beam size. The 20Ne/22Ne ratios for the different size standards were normalized to the 20Ne/22Ne ratio of the largest standard (10−14 moles of 20Ne). The error bars (2σ uncertainties) reflect the relative errors in the 20Ne/22Ne isotope ratio based on the reproducibility of the standards. bd, Reproducibility of standard 20Ne/22Ne ratios that were interspersed with the sample measurements over the 3-month period that it took to conduct all step-crushes. Error bars on the individual air standards represent the internal measurement error (2SE), while the dashed lines represent the long-term (2σ) external reproducibility. The external reproducibilities on the 20Ne/22Ne ratios were 0.03, 0.03 and 0.01 (2σ) for 20Ne beam sizes of 1.6 × 10−15 moles (n = 26), 3.7 × 10−15 moles (n = 17) and 1 × 10−14 moles (n = 114), respectively.

  5. Extended Data Table 1 Maximum measured 20Ne/22Ne and 21Ne/22Ne ratios for non-plume-influenced MORBs and plume-influenced materials
  6. Extended Data Table 2 Noble gas end-member compositions

Supplementary information

  1. Supplementary Table 1

    Noble gas abundances and isotope ratios for the individual step-crushes of the two plume-influenced MORBs. Two to five grams of basaltic glass was chipped from pillow lavas, loaded into a stainless-steel piston crusher, step-crushed under ultra-high vacuum, and then let into the Nu Noblesse mass spectrometer in the UC Davis Noble Gas Laboratory.

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