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Antarctic weathering and carbonate compensation at the Eocene–Oligocene transition


During the Eocene–Oligocene transition about 34 million years ago, permanent ice cover developed on Antarctica. This pronounced climate transition was accompanied by the deepening of the carbonate compensation depth in the oceans1 and perturbations in atmospheric carbon dioxide concentrations2,3. These changes may have been linked to continental weathering on Antarctica, but reconstructing which rock types were subject to weathering and the intensity of that weathering has proved challenging. Here we compare the lead (Pb) isotope values of seawater as recorded by extractions from decarbonated bulk sediments and those of silicate detrital fractions from deep-sea sediments from sites in the Southern Ocean that span the Eocene–Oligocene transition. These comparisons allowed us to assess local weathering inputs of Pb from Antarctica. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios suggest high rates of chemical weathering in the late Eocene, which would have helped draw down atmospheric CO2 to levels necessary for glacial initiation. Mechanical weathering and the introduction of newly exposed material was enhanced during the establishment of the Antarctic ice sheet. We also observe a divergence of seawater 206Pb/204Pb from detrital values during the Eocene–Oligocene transition, which implies an additional source of weathered material. We argue that the weathering of carbonate basement rock from Antarctica could explain the 206Pb/204Pb trend, and could have contributed to the observed deepening of the carbonate compensation depth through contributions to ocean alkalinity.

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Figure 1: Seawater and detrital silicate Pb and Nd isotopes versus age for sites 738 and 689.
Figure 2: Proxy responses to the Eocene/Oligocene glaciation of Antarctica.


  1. Coxall, H. K., Wilson, P. A., Pälike, H., Lear, C. H. & Backman, J. Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacific Ocean. Nature 433, 53–57 (2005).

    Article  Google Scholar 

  2. Pearson, P. N., Foster, G. L. & Wade, B. S. Atmospheric carbon dioxide through the Eocene–Oligocene climate transition. Nature 461, 1110–1113 (2009).

    Article  Google Scholar 

  3. Pagani, M. et al. The role of carbon dioxide during the onset of Antarctic glaciation. Science 334, 1261–1264 (2011).

    Article  Google Scholar 

  4. Erel, Y., Harlavan, Y. & Blum, J. D. Lead isotope systematics of granitoid weathering. Geochim. Cosmochim. Acta 58, 5299–5306 (1994).

    Article  Google Scholar 

  5. Harlavan, Y., Erel, Y. & Blum, J. D. Systematic changes in lead isotopic composition with soil age in glacial granitic terrains. Geochim. Cosmochim. Acta 62, 33–46 (1998).

    Article  Google Scholar 

  6. Von Blanckenburg, F. & Nägler, T. F. Weathering versus circulation-controlled changes in radiogenic isotope tracer composition of the Labrador Sea and North Atlantic deep water. Paleoceanography 16, 424–434 (2001).

    Article  Google Scholar 

  7. Gutjahr, M. et al. Reliable extraction of a deepwater trace metal isotope signal from Fe–Mn oxyhydroxide coatings of marine sediments. Chem. Geol. 242, 351–370 (2007).

    Article  Google Scholar 

  8. Basak, C., Martin, E. E. & Kamenov, G. D. Seawater Pb isotopes extracted from Cenozoic marine sediments. Chem. Geol. 286, 94–108 (2011).

    Google Scholar 

  9. Lear, C. H., Bailey, T. R., Pearson, P. N., Coxall, H. K. & Rosenthal, Y. Cooling and ice growth across the Eocene–Oligocene transition. Geology 36, 251–254 (2008).

    Article  Google Scholar 

  10. Scher, H. D., Bohaty, S. M., Zachos, J. C. & Delaney, M. L. Two-stepping into the icehouse: East Antarctic weathering during progressive ice-sheet expansion at the Eocene–Oligocene transition. Geology 39, 383–386 (2011).

    Article  Google Scholar 

  11. Goldstein, S. L. & Hemming, S. H. in Treatise on Geochemistry (ed. Elderfield, H.) 453–489 (Elsevier, 2003).

    Book  Google Scholar 

  12. Scher, H. D. & Martin, E. E. Oligocene deep water export from the North Atlantic and the development of the Antarctic Circumpolar Current examined with neodymium isotopes. Paleoceanography 23, PA1205 (2008).

    Article  Google Scholar 

  13. Scher, H. D. & Martin, E. E. Timing and climatic consequences of the opening of Drake passage. Science 312, 428–430 (2006).

    Article  Google Scholar 

  14. Robert, C. & Kennett, J. P. Antarctic continental weathering changes during Eocene–Oligocene cryosphere expansion: Clay mineral and oxygen isotope evidence. Geology 25, 587–590 (1997).

    Article  Google Scholar 

  15. Zachos, J. C., Opdyke, B. N., Quinn, T. M., Jones, C. E. & Halliday, A. N. Early Cenozoic glaciation, Antarctic weathering, and seawater 87Sr/86Sr: Is there a link? Chem. Geol. 161, 165–180 (1999).

    Article  Google Scholar 

  16. Anderson, S. P., Drever, J. I. & Humphrey, N. F. Chemical weathering in glacial environments. Geology 25, 399–402 (1997).

    Article  Google Scholar 

  17. Foster, G. L. & Vance, D. Negligible glacial–interglacial variation in continental chemical weathering rates. Nature 444, 918–921 (2006).

    Article  Google Scholar 

  18. Gutjahr, M., Frank, M., Halliday, A. N. & Keigwin, L. D. Retreat of the Laurentide ice sheet tracked by the isotopic composition of Pb in western North Atlantic seawater during termination 1. Earth Planet. Sci. Lett. 286, 546–555 (2009).

    Article  Google Scholar 

  19. Kurzweil, F., Gutjahr, M., Vance, D. & Keigwin, L. Authigenic Pb isotopes from the Laurentian Fan: Changes in chemical weathering and patterns of North American freshwater runoff during the last deglaciation. Earth Planet. Sci. Lett. 299, 458–465 (2010).

    Article  Google Scholar 

  20. Crocket, K. C., Vance, D., Foster, G. L., Richards, D. A. & Tranter, M. Continental weathering fluxes during the last glacial/interglacial cycle: Insights from the marine sedimentary Pb isotope record at Orphan Knoll, NW Atlantic. Quaternary. Sci. Rev. 38, 89–99 (2012).

    Article  Google Scholar 

  21. Chen, J. H., Edwards, R. L. & Wasserburg, G. J. 238U, 234U and 232Th in seawater. Earth Planet. Sci. Lett. 80, 241–251 (1986).

    Article  Google Scholar 

  22. Fairchild, I. J., Bradby, L., Sharp, M. & Tison, J. L. Hydrochemistry of carbonate terrains in alpine glacial settings. Earth Surf. Proc. Land. 19, 33–54 (1994).

    Article  Google Scholar 

  23. Elliot, D. H. Tectonics of Antarctica: A review. Am. J. Sci. 275, 45–106 (1975).

    Google Scholar 

  24. Rowell, A. J. & Rees, M. N. in Geological Evolution of Antarctica (eds Thomson, M. R. A., Crame, J. A. & Thomson, J. W.) (Cambridge Univ. Press, 1987).

    Google Scholar 

  25. Goodge, J. W., Myrow, P., Williams, I. S. & Bowring, S. A. Age and provenance of the Beardmore group, Antarctica: Constraints on Rodinia supercontinent breakup. J. Geol. 110, 393–406 (2002).

    Article  Google Scholar 

  26. DeConto, R. M. & Pollard, D. Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2 . Nature 421, 245–249 (2003).

    Article  Google Scholar 

  27. Swart, P. K. & Eberli, G. The nature of δ13C of periplatform sediments: Implications for stratigraphy and the global carbon cycle. Sediment. Geol. 175, 115–129 (2005).

    Article  Google Scholar 

  28. Pekar, S. F., Christie-Blick, N., Kominz, M. A. & Miller, K. G. Calibration between eustatic estimates from backstripping and oxygen isotopic records for the Oligocene. Geology 30, 903–906 (2002).

    Article  Google Scholar 

  29. Merico, A., Tyrrell, T. & Wilson, P. A. Eocene/Oligocene ocean de-acidification linked to Antarctic glaciation by sea-level fall. Nature 452, 979–982 (2008).

    Article  Google Scholar 

  30. Scher, H. D. & Martin, E. E. Circulation in the Southern Ocean during the Paleogene. Earth Planet. Sci. Lett. 228, 391–405 (2004).

    Article  Google Scholar 

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We thank G. Kamenov for technical support regarding Nd and Pb isotopic analyses on the Nu Plasma MC-ICPMS at the University of Florida and P. Muller for scientific discussions. Funding for this research was provided by NSF grant OCE0926474 to E.E.M.

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C.B. and E.E.M. conceived the study. C.B. analysed the Nd and Pb isotope data. Both authors contributed towards writing the manuscript.

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Correspondence to Chandranath Basak.

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The authors declare no competing financial interests.

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Basak, C., Martin, E. Antarctic weathering and carbonate compensation at the Eocene–Oligocene transition. Nature Geosci 6, 121–124 (2013).

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