Displaced cratonic mantle concentrates deep carbon during continental rifting


Continental rifts are important sources of mantle carbon dioxide (CO2) emission into Earth’s atmosphere1,2,3. Because deep carbon is stored for long periods in the lithospheric mantle4,5,6, rift CO2 flux depends on lithospheric processes that control melt and volatile transport1,3,7. The influence of compositional and thickness differences between Archaean and Proterozoic lithosphere on deep-carbon fluxes remains untested. Here we propose that displacement of carbon-enriched Tanzanian cratonic mantle concentrates deep carbon below parts of the East African Rift System. Sources and fluxes of CO2 and helium are examined over a 350-kilometre-long transect crossing the boundary between orogenic (Natron and Magadi basins) and cratonic (Balangida and Manyara basins) lithosphere from north to south. Areas of diffuse CO2 degassing exhibit increasing mantle CO2 flux and 3He/4He ratios as the rift transitions from Archaean (cratonic) to Proterozoic (orogenic) lithosphere. Active carbonatite magmatism also occurs near the craton edge. These data indicate that advection of the root of thick Archaean lithosphere laterally to the base of the much thinner adjacent Proterozoic lithosphere creates a zone of highly concentrated deep carbon. This mode of deep-carbon extraction may increase CO2 fluxes in some continental rifts, helping to control the production and location of carbonate-rich magmas.

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Fig. 1: CO2 flux and carbon and helium isotope data in the study region.
Fig. 2: Distribution of <45-Myr-old carbonatite systems associated with the EARS and the Archaean Tanzanian craton.
Fig. 3: Latitudinal variations in CO2 flux and RA values for 3He/4He with respect to the modelled lithosphere structure.
Fig. 4: Proposed model for deep-carbon transport along a cratonic boundary in the EARS study region.

Data availability

All data generated or analysed during this study are provided with this article and in Supplementary Tables 14. The SRTM digital elevation model used to generate maps is publicly available at http://srtm.csi.cgiar.org/srtmdata. The recently analysed and previously unpublished CO2 flux and isotopic data (https://doi.org/10.26022/IEDA/111520) from the 2018 Tanzania field campaign can be found at http://www.earthchem.org.


  1. 1.

    Lee, H. et al. Massive and prolonged deep carbon emissions associated with continental rifting. Nat. Geosci. 9, 145–149 (2016).

    ADS  CAS  Google Scholar 

  2. 2.

    Brune, S., Williams, S. E. & Müller, R. D. Potential links between continental rifting, CO2 degassing and climate change through time. Nat. Geosci. 10, 941–946 (2017).

    ADS  CAS  Google Scholar 

  3. 3.

    Tamburello, G., Pondrelli, S., Chiodini, G. & Rouwet, D. Global-scale control of extensional tectonics on CO2 earth degassing. Nat. Commun. 9, 4608 (2018).

    ADS  PubMed  PubMed Central  Google Scholar 

  4. 4.

    Dasgupta, R. & Hirschmann, M. M. The deep carbon cycle and melting in Earth’s interior. Earth Planet. Sci. Lett. 298, 1–13 (2010).

    ADS  CAS  Google Scholar 

  5. 5.

    Kelemen, P. B. & Manning, C. E. Reevaluating carbon fluxes in subduction zones, what goes down, mostly comes up. Proc. Natl Acad. Sci. USA 112, E3997–E4006 (2015).

    ADS  CAS  PubMed  Google Scholar 

  6. 6.

    Foley, S. F. & Fischer, T. P. An essential role for continental rifts and lithosphere in the deep carbon cycle. Nat. Geosci. 10, 897–902 (2017).

    ADS  CAS  Google Scholar 

  7. 7.

    Hunt, J. A., Zafu, A., Mather, T. A., Pyle, D. M. & Barry, P. H. Spatially variable CO2 degassing in the main Ethiopian rift: implications for magma storage, volatile transport, and rift-related emissions. Geochem. Geophys. Geosyst. 18, 3714–3737 (2017).

    ADS  CAS  Google Scholar 

  8. 8.

    Malusà, M. G. et al. Active carbon sequestration in the Alpine mantle wedge and implications for long-term climate trends. Sci. Rep. 8, 4740–4748 (2018).

    ADS  PubMed  PubMed Central  Google Scholar 

  9. 9.

    Foley, S. F. Rejuvenation and erosion of the cratonic lithosphere. Nat. Geosci. 1, 503–510 (2008).

    ADS  CAS  Google Scholar 

  10. 10.

    Brantley, S. L. & Koepenick, K. W. Measured carbon-dioxide emissions from Oldoinyo Lengai and the skewed distribution of passive volcanic fluxes. Geology 23, 933–936 (1995).

    ADS  CAS  Google Scholar 

  11. 11.

    Sawyer, G. M., Carn, S. A., Tsanev, V. I., Oppenheimer, C. & Burton, M. Investigation into magma degassing at Nyiragongo volcano, Democratic Republic of the Congo. Geochem. Geophys. Geosyst. 9, Q02017 (2008).

    ADS  Google Scholar 

  12. 12.

    Hutchison, W. et al. Structural controls on fluid pathways in an active rift system: a case study of the Aluto volcanic complex. Geosphere 11, 542–562 (2015).

    ADS  Google Scholar 

  13. 13.

    van Wijk, J., van Hunen, J. & Goes, S. Small-scale convection during continental rifting: evidence from the Rio Grande rift. Geology 36, 575–578 (2008).

    ADS  Google Scholar 

  14. 14.

    Bastow, I. D., Keir, D. & Daly, E. The Ethiopia Afar Geoscientific Lithospheric Experiment (EAGLE): probing the transition from continental rifting to incipient seafloor spreading. Spec. Pap. Geol. Soc. Am. 478, 1–26 (2011).

    Google Scholar 

  15. 15.

    Ebinger, C. J. & Sleep, N. H. Cenozoic magmatism throughout east Africa resulting from impact of a single plume. Nature 395, 788–791 (1998).

    ADS  CAS  Google Scholar 

  16. 16.

    Foley, S. F., Link, K., Tiberindwa, J. V. & Barifaijo, E. Patterns and origin of igneous activity around the Tanzanian craton. J. Afr. Earth Sci. 62, 1–18 (2012).

    ADS  CAS  Google Scholar 

  17. 17.

    Kalt, A., Hegner, E. & Satir, M. Nd, Sr, and Pb isotopic evidence for diverse lithospheric mantle sources of East African Rift carbonatites. Tectonophysics 278, 31–45 (1997).

    ADS  CAS  Google Scholar 

  18. 18.

    Rosenthal, A., Foley, S. F., Pearson, D. G., Nowell, G. M. & Tappe, S. Petrogenesis of strongly alkaline primitive volcanic rocks at the propagating tip of the western branch of the East African Rift. Earth Planet. Sci. Lett. 284, 236–248 (2009).

    ADS  CAS  Google Scholar 

  19. 19.

    Currie, C. A. & van Wijk, J. How craton margins are preserved: insights from geodynamic models. J. Geodyn. 100, 144–158 (2016).

    Google Scholar 

  20. 20.

    Roecker, S. et al. Subsurface images of the Eastern Rift, Africa, from the joint inversion of body waves, surface waves and gravity: investigating the role of fluids in early-stage continental rifting. Geophys. J. Int. 210, 931–950 (2017).

    ADS  Google Scholar 

  21. 21.

    Tiberi, C. et al. Lithospheric modification by extension and magmatism at the craton–orogenic boundary: north Tanzania divergence, East Africa. Geophys. J. Int. 216, 1693–1710 (2019).

    ADS  CAS  Google Scholar 

  22. 22.

    Ebinger, C. J. et al. Crustal structure of active deformation zones in Africa: implications for global crustal processes. Tectonics 36, 3298–3332 (2017).

    ADS  Google Scholar 

  23. 23.

    Lee, C. T. & Rudnick, R. L. Compositionally stratified cratonic lithosphere: petrology and geochemistry of peridotite xenoliths from the Labait tuff cone, Tanzania. In Proc. of the 7th International Kimberlite Conference (eds Gurney, J. J. & Richardson, S. R.) 503–309 (National Book Printers, 1999).

  24. 24.

    Vauchez, A., Dineur, F. & Rudnick, R. Microstructure, texture and seismic anisotropy of the lithospheric mantle above a mantle plume: insights from the Labait volcano xenoliths (Tanzania). Earth Planet. Sci. Lett. 232, 295–314 (2005).

    ADS  CAS  Google Scholar 

  25. 25.

    Aulbach, S., Rudnick, R. L. & McDonough, W. F. Evolution of the lithospheric mantle beneath the East African Rift in Tanzania and its potential signatures in rift magmas. Spec. Pap. Geol. Soc. Am. 478, 105–125 (2011).

    Google Scholar 

  26. 26.

    Weinstein, A. et al. Fault-magma interactions during early continental rifting: seismicity of the Magadi–Natron–Manyara basins, Africa. Geochem. Geophys. Geosyst. 18, 3662–3686 (2017).

    ADS  Google Scholar 

  27. 27.

    Lee, H. et al. Incipient rifting accompanied by the release of subcontinental lithospheric mantle volatiles in the Magadi and Natron basin, East Africa. J. Volcanol. Geotherm. Res. 346, 118–133 (2017).

    ADS  CAS  Google Scholar 

  28. 28.

    Gautheron, C. & Moreira, M. Helium signature of the subcontinental lithospheric mantle. Earth Planet. Sci. Lett. 199, 39–47 (2002).

    ADS  CAS  Google Scholar 

  29. 29.

    Mana, S., Furman, T., Turrin, B. D., Feigenson, M. D. & Swisher, C. C. Magmatic activity across the East African North Tanzanian Divergence Zone. J. Geol. Soc. Lond. 172, 368–389 (2015).

    CAS  Google Scholar 

  30. 30.

    Halldórsson, S. A., Hilton, D. R., Scarsi, P., Abebe, T. & Hopp, J. A common mantle plume source beneath the entire East African Rift System revealed by coupled helium- neon systematics. Geophys. Res. Lett. 41, 2304–2311 (2014).

    ADS  Google Scholar 

  31. 31.

    Furman, T. et al. Heads and tails: 30 million years of the Afar plume. Geol. Soc. Lond. Spec. Publ. 259, 95–119 (2006).

    ADS  CAS  Google Scholar 

  32. 32.

    Furman, T. Geochemistry of East African Rift basalts: an overview. J. Afr. Earth Sci. 48, 147–160 (2007).

    ADS  CAS  Google Scholar 

  33. 33.

    Pik, R., Marty, B. & Hilton, D. R. How many mantle plumes in Africa? The geochemical point of view. Chem. Geol. 226, 100–114 (2006).

    ADS  CAS  Google Scholar 

  34. 34.

    Hilton, D. R. et al. Helium isotopes at Rungwe Volcanic Province, Tanzania, and the origin of East African Plateaux. Geophys. Res. Lett. 38, L21304 (2011).

    ADS  Google Scholar 

  35. 35.

    Selway, K. Negligible effect of hydrogen content on plate strength in East Africa. Nat. Geosci. 8, 543–546 (2015).

    ADS  CAS  Google Scholar 

  36. 36.

    Koornneef, J. M. et al. Nature and timing of multiple metasomatic events in the sub-cratonic lithosphere beneath Labait, Tanzania. Lithos 112, 896–912 (2009).

    ADS  Google Scholar 

  37. 37.

    Stachel, T. & Brey, G. P. Rare and unusual mineral inclusions in diamonds from Mwadui, Tanzania. Contrib. Mineral. Petrol. 132, 34–47 (1998).

    ADS  CAS  Google Scholar 

  38. 38.

    Rudnick, R. L., Mcdonough, W. F. & Chappell, B. W. Carbonatite metasomatism in the northern Tanzanian mantle: petrographic and geochemical characteristics. Earth Planet. Sci. Lett. 114, 463–475 (1993).

    ADS  CAS  Google Scholar 

  39. 39.

    Huismans, R. & Beaumont, C. Depth-dependent extension, two-stage breakup and cratonic underplating at rifted margins. Nature 473, 74–78 (2011).

    ADS  CAS  PubMed  Google Scholar 

  40. 40.

    Chesley, J. T., Rudnick, R. L. & Lee, C.-T. Re–Os systematics of mantle xenoliths from the East African Rift: age, structure, and history of the Tanzanian craton. Geochim. Cosmochim. Acta 63, 1203–1217 (1999).

    ADS  CAS  Google Scholar 

  41. 41.

    Foley, S. F. et al. The composition of near-solidus melts of peridotite in the presence of CO2 and H2O between 40 and 60 kbar. Lithos 112, 274–283 (2009).

    ADS  Google Scholar 

  42. 42.

    Conrad, C. P. & Behn, M. D. Constraints on lithosphere net rotation and asthenospheric viscosity from global mantle flow models and seismic anisotropy. Geochem. Geophys. Geosyst. 11, Q05W05 (2010).

    Google Scholar 

  43. 43.

    Fischer, T. P. et al. Upper-mantle volatile chemistry at Oldoinyo Lengai volcano and the origin of carbonatites. Nature 459, 77–80 (2009).

    ADS  CAS  PubMed  Google Scholar 

  44. 44.

    Carn, S. A., Fioletov, V. E., McLinden, C. A., Li, C. & Krotkov, N. A. A decade of global volcanic SO2 emissions measured from space. Sci. Rep. 7, 44095 (2017).

    ADS  CAS  PubMed  PubMed Central  Google Scholar 

  45. 45.

    Sawyer, G. M., Carn, S. A., Tsanev, V. I., Oppenheimer, C. & Burton, M. Investigation into magma degassing at Nyiragongo volcano, Democratic Republic of the Congo. Geochem. Geophys. Geosyst. 9, Q02017 (2008).

    ADS  Google Scholar 

  46. 46.

    Eby, G. N., Lloyd, F. E. & Woolley, A. R. Geochemistry and petrogenesis of the Fort Portal, Uganda, extrusive carbonatite. Lithos 113, 785–800 (2009).

    ADS  CAS  Google Scholar 

  47. 47.

    Roberts, E. M. et al. Initiation of the western branch of the East African Rift coeval with the eastern branch. Nat. Geosci. 5, 289–294 (2012).

    ADS  CAS  Google Scholar 

  48. 48.

    Parks, M. M. et al. Distinguishing contributions to diffuse CO2 emissions in volcanic areas from magmatic degassing and thermal decarbonation using soil gas 222Rn–δ13C systematics: application to Santorini volcano, Greece. Earth Planet. Sci. Lett. 377, 180–190 (2013).

    ADS  Google Scholar 

  49. 49.

    Kennett, B. L. N. & Engdahl, E. R. Traveltimes for global earthquake location and phase identification. Geophys. J. Int. 105, 429–465 (1991).

    ADS  Google Scholar 

  50. 50.

    Dawson, J. B., James, D., Paslick, C. & Halliday, A. M. Ultrabasic potassic low-volume magmatism and continental rifting in north-central Tanzania: association with enhanced heat flow. Russ. Geol. Geophys. 38, 69–81 (1997).

    Google Scholar 

  51. 51.

    Ibs-von Seht, M., Blumenstein, S., Wagner, R., Hollnack, D. & Wohlenberg, J. Seismicity, seismotectonics and crustal structure of the southern Kenya Rift—new data from the Lake Magadi area. Geophys. J. Int. 146, 439–453 (2001).

    ADS  Google Scholar 

  52. 52.

    Ernst, R. E. & Bell, K. Large igneous provinces (LIPs) and carbonatites. Mineral. Petrol. 98, 55–76 (2010).

    ADS  CAS  Google Scholar 

  53. 53.

    Hofmann, C. et al. Timing of the Ethiopian flood basalt event and implications for plume birth and global change. Nature 389, 838–841 (1997).

    ADS  CAS  Google Scholar 

  54. 54.

    Rooney, T. O. The Cenozoic magmatism of East-Africa: Part I – flood basalts and pulsed magmatism. Lithos 286–287, 264–301 (2017).

    ADS  Google Scholar 

  55. 55.

    Woolley, A. R. & Kjarsgaard, B. A. Carbonatite Occurrences of the World (Geological Survey of Canada, 2008).

  56. 56.

    Fairhead, J. D., Mitchell, J. G. & Williams, L. A. J. New K/Ar determinations on rift volcanics of S. Kenya and their bearing on age of rift faulting. Science 238, 66–69 (1972).

    Google Scholar 

  57. 57.

    Le Gall, B. et al. Rift propagation at craton margin. Distribution of faulting and volcanism in the North Tanzanian Divergence (East Africa) during Neogene times. Tectonophysics 448, 1–19 (2008).

    ADS  Google Scholar 

  58. 58.

    Muirhead, J. D. et al. Evolution of upper crustal faulting assisted by magmatic volatile release during early-stage continental rift development in the East African Rift. Geosphere 12, 1670–1700 (2016).

    ADS  Google Scholar 

  59. 59.

    Sherrod, D. R., Magigita, M. M. & Kwelwa, S. Geologic Map of Oldonyo Lengai (Oldoinyo Lengai) and Surroundings, Arusha Region, United Republic of Tanzania. Report No. 1306 (U.S. Geological Survey, 2013).

  60. 60.

    Muirhead, J. D., Kattenhorn, S. A. & Le Corvec, N. Varying styles of magmatic strain accommodation in the East African Rift. Geochem. Geophys. Geosyst. 16, 2775– 2795 (2015).

    ADS  Google Scholar 

  61. 61.

    Bagdasaryan, G., Gerasimovskiy, V. I., Polykov, A. I. & Gukasyan, R. K. Age of volcanic rocks in the rift zones of East Africa. Geokhimiya 1, 84–90 (1973).

    Google Scholar 

  62. 62.

    Mollel, G. F. Petrochemistry and Geochronology of Ngorongoro Volcanic Highland Complex (NVHC) and its Relationship to Laetoli and Olduvai Gorge, Tanzania. PhD thesis, Rutgers Univ. (2007).

  63. 63.

    Burton, M. R., Sawyer, G. M. & Granieri, D. in Carbon in Earth (eds. Hazen, R. M. et al.) 323–354 (De Gruyter, 2013).

  64. 64.

    Sano, Y., Tokutake, T. & Takahata, N. Accurate measurement of atmospheric helium isotopes. Anal. Sci. 24, 521–525 (2008).

    CAS  PubMed  Google Scholar 

  65. 65.

    Chiodini, G., Cioni, R., Guidi, M., Raco, B. & Marini, L. Soil CO2 flux measurements in volcanic and geothermal areas. Appl. Geochem. 13, 543–552 (1998).

    CAS  Google Scholar 

  66. 66.

    Chiodini, G. et al. Carbon isotopic composition of soil CO2 efflux, a powerful method to discriminate different sources feeding soil CO2 degassing in volcanic-hydrothermal areas. Earth Planet. Sci. Lett. 274, 372–379 (2008).

    ADS  CAS  Google Scholar 

  67. 67.

    Sinclair, J. A. Selection of thresholds in geochemical data using probability graphs. J. Geochem. Explor. 3, 129–149 (1974).

    CAS  Google Scholar 

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This work was funded by the NSF EAR GeoPRISMS Program, grant numbers 1654518 (J.D.M.), 1654433 (T.P.F.) and 1836651 (J.D.), Deutsche Forschungsgemeinschaft (DFG) grant RE 4321/1-1 (M.C.R.) and the Marshall-Heape fund at Tulane University (C.J.E.). We are grateful to COSTECH and Tanzania Wildlife Research Institute for permitting us to conduct research in Tanzania. We thank E. Saria and K. Nkembo for assistance during fieldwork in the Lake Natron region in 2018, G. Kianji for assistance during collection of data in 2014, and K. Rahilly for assisting with field planning.

Author information




The initial project was conceived by J.D.M., T.P.F., C.J.E. and J.D., with planning and execution of field data collection by J.D.M., T.P.F., C.J.E., A.L., S.J.O., E.K. and M.C.R. CO2 flux data were compiled and analysed by J.D.M., T.P.F., E.J.J., S.J.O. and A.L., and laboratory analyses of helium and carbon isotopes were performed by T.P.F., H.L., Y.S. and N.T. Compilation and examination of geophysical and gas chemical data were conducted by C.T., J.D.M., C.J.E., J.v.W. and C.A.C. The final model presented in Fig. 4 was conceived and designed by T.P.F., J.D.M., C.J.E., J.v.W., C.A.C. and S.F.F. The manuscript was written by J.D.M. and T.P.F. with contributions from all co-authors.

Corresponding authors

Correspondence to James D. Muirhead or Tobias P. Fischer.

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The authors declare no competing interests.

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Peer review information Nature thanks Sascha Brune, Giovanni Chiodini and Tanya Furman for their contribution to the peer review of this work.

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Extended data figures and tables

Extended Data Fig. 1 Latitudinal variations in CO2 flux and RA values (3He/4He) with respect to the modelled lithosphere structure.

a, RA versus latitude along the Eastern Rift from −1.5° to −4.5°. Air-contaminated samples (TZ18-C16) were removed from the analysis. The Tanzanian craton boundary (light grey) is interpreted using the sharp density (c) and velocity (d) contrasts near the northern Manyara and southern Natron basins. It is marked as a broad region to account for location uncertainties and the overall three-dimensional nature of the boundary in the region. b, Diffuse CO2 flux versus latitude along the Eastern Rift from −1.5° to −4.5° for sample sites presented in Fig. 1a and the Oldoinyo Lengai volcano. c, Lithosphere density model from Tiberi et al.21. d, Lithosphere velocity model from Tiberi et al.21 (model resolution discussed in Methods). The density and velocity contrasts are relative to the IASP91 model49. The position of the cross-section is shown in Fig. 1a.

Extended Data Fig. 2 CO2 flux population analyses.

ad, Shown are results for the Manyara (a), Natron (b), Magadi (c) and Balangida (d) basins. The analyses were performed in line with the method of Sinclair67 outlined in Chiodini et al.65, with the dashed lines representing a modelled mixed population based on the distributions of the lower, higher and occasionally intermediate flux populations.

Supplementary information

Supplementary Table 1

Data Table 1 provides a summary of diffuse CO2 flux data (g m-2 d-1) for the Magadi, Natron, Manyara, and Balangida basins (values presented as “<0.24” are below the detection limit of the flux meter).

Supplementary Table 2

Data Table 2 is a summary of carbon isotope data.

Supplementary Table 3

Data Table 3 provides a summary of helium isotope data.

Supplementary Table 4

Data Table 4 summarizes the carbonatite systems associated with the Tanzanian craton and EARS.

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Muirhead, J.D., Fischer, T.P., Oliva, S.J. et al. Displaced cratonic mantle concentrates deep carbon during continental rifting. Nature 582, 67–72 (2020). https://doi.org/10.1038/s41586-020-2328-3

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