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Hydrological impact of Middle Miocene Antarctic ice-free areas coupled to deep ocean temperatures

Nature Geoscience volume 14, pages 429–436 (2021)Cite this article

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Abstract

Oxygen isotopes from ocean sediments (δ18O) used to reconstruct past continental ice volumes additionally record deep water temperatures (DWTs). Traditionally, these are assumed to be coupled (ice-volume changes cause DWT changes). However, δ18O records during peak Middle Miocene warmth (~16–15 million years ago) document large rapid fluctuations (~1–1.5‰) difficult to explain as huge Antarctic ice sheet (AIS) volume changes. Here, using climate modelling and data comparisons, we show DWTs are coupled to AIS spatial extent, not volume, because Antarctic albedo changes modify the hydrological cycle, affecting Antarctic deep water production regions. We suggest the Middle Miocene AIS had retreated substantially from previous Oligocene maxima. The residual ice sheet varied spatially more rapidly on orbital timescales than previously thought, enabling large DWT swings (up to 4 °C). When Middle Miocene warmth terminated (~13 million years ago) and a continent-scale AIS had stabilized, further ice-volume changes were predominantly in height rather than extent, with little impact on DWT. Our findings imply a shift in ocean sensitivity to ice-sheet changes occurs when AIS retreat exposes previously ice-covered land; associated feedbacks could reduce the Earth system’s ability to maintain a large AIS. This demonstrates ice-sheet changes should be characterized not only by ice volume but also by spatial extent.

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Fig. 1: Middle Miocene benthic (Cibicidoides spp.) oxygen isotope, DWT and sea-level changes.
Fig. 2: Orography and ice-sheet configurations.
Fig. 3: Annual mean Southern Hemisphere DWT estimates averaged between 2 and 3 km, simulated with different-sized Antarctic ice sheets.
Fig. 4: Middle Miocene atmospheric CO2 reconstructions.
Fig. 5: Simulated atmospheric and oceanographic conditions with different-sized Antarctic ice sheets.
Fig. 6: Annual mean Southern Hemisphere DWT estimates averaged between 2 and 3 km, simulated with different-sized Antarctic ice sheets and CO2 concentration.

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Data availability

The climate model output data are available for analysis and download at https://www.paleo.bristol.ac.uk/ummodel/scripts/papers/Bradshaw_et_al_2021.html. It is possible to reproduce the information in Figs. 2, 3, 5 and 6 via this interface as well as download the data itself and the ancillary information (palaeogeography and ice-sheet configuration).

Code availability

The UK Met Office made available the source code of HadCM3 via the Ported Unified Model release (https://www.metoffice.gov.uk/research/approach/collaboration/unified-model/partnership). Enquiries regarding the use of HadCM3 should be directed in the first instance to the UM Partnership team, who can be contacted at um_collaboration@metoffice.gov.uk. The main repository for the Met Office Unified Model (UM) version corresponding to the model presented here can be viewed at http://cms.ncas.ac.uk/code_browsers/UM4.5/UMbrowser/index.html (registration required). The code detailing the changes required to update HadCM3 to HadCM3LB-M2.1 are available as a supplement to Valdes et al.28.

Change history

  • 23 June 2021

    In the online PDF version of this Article originally published, owing to a technical issue Fig. 5 was appearing incorrectly as a grey box; this has now been corrected. The HTML and print versions were unaffected.

References

  1. Zachos, J., Pagani, M., Sloan, L., Thomas, E. & Billups, K. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science 292, 686–693 (2001).

    Article  Google Scholar 

  2. Chappell, J. & Shackleton, N. Oxygen isotopes and sea level. Nature 324, 137–140 (1986).

    Article  Google Scholar 

  3. Shackleton, N. J. & Kennett, J. P. in Initial Reports of Deep Sea Drilling Project Vol. 29, Report 17 (US Government Printing Office, 1975); https://doi.org/10.2973/dsdp.proc.29.117.1975

  4. Lewis, A. R. et al. Mid-Miocene cooling and the extinction of tundra in continental Antarctica. Proc. Natl Acad. Sci. USA 105, 10676–10680 (2008).

    Article  Google Scholar 

  5. Kleman, J. & Glasser, N. F. The subglacial thermal organisation (STO) of ice sheets. Quat. Sci. Rev. 26, 585–597 (2007).

    Article  Google Scholar 

  6. Levy, R. H. et al. Antarctic ice-sheet sensitivity to obliquity forcing enhanced through ocean connections. Nat. Geosci. 12, 132–137 (2019).

    Article  Google Scholar 

  7. Langebroek, P. M., Paul, A. & Schulz, M. Antarctic ice-sheet response to atmospheric CO2 and insolation in the Middle Miocene. Clim. Past 5, 633–646 (2009).

    Article  Google Scholar 

  8. Lear, C. H., Mawbey, E. M. & Rosenthal, Y. Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states. Paleoceanography 25, PA4215 (2010).

    Article  Google Scholar 

  9. Lear, C. H. et al. Neogene ice volume and ocean temperatures: insights from infaunal foraminiferal Mg/Ca paleothermometry. Paleoceanography 30, 1437–1454 (2015).

    Article  Google Scholar 

  10. de Boer, B., van de Wal, R. S. W., Lourens, L. J. & Bintanja, R. Transient nature of the Earth’s climate and the implications for the interpretation of benthic δ18O records. Palaeogeogr. Palaeoclimatol. Palaeoecol. 335, 4–11 (2012).

    Article  Google Scholar 

  11. Miller, K. G. et al. Cenozoic sea-level and cryospheric evolution from deep-sea geochemical and continental margin records. Sci. Adv. 6, eaaz1346 (2020).

    Article  Google Scholar 

  12. Langebroek, P. M., Paul, A. & Schulz, M. Simulating the sea level imprint on marine oxygen isotope records during the Middle Miocene using an ice sheet–climate model. Paleoceanography 25, PA4203 (2010).

    Article  Google Scholar 

  13. Gasson, E., DeConto, R. M., Pollard, D. & Levy, R. H. Dynamic Antarctic ice sheet during the Early to Mid-Miocene. Proc. Natl Acad. Sci. USA 113, 3459–3464 (2016).

    Article  Google Scholar 

  14. Kominz, M. A. et al. Late Cretaceous to Miocene sea‐level estimates from the New Jersey and Delaware coastal plain coreholes: an error analysis. Basin Res. 20, 211–226 (2008).

    Article  Google Scholar 

  15. Miller, K. G. et al. The Phanerozoic record of global sea-level change. Science 310, 1293–1298 (2005).

    Article  Google Scholar 

  16. Kominz, M. A., Miller, K. G., Browning, J. V., Katz, M. E. & Mountain, G. S. Miocene relative sea level on the New Jersey shallow continental shelf and coastal plain derived from one-dimensional backstripping: a case for both eustasy and epeirogeny. Geosphere 12, 1437–1456 (2016).

    Article  Google Scholar 

  17. John, C. M. et al. Timing and magnitude of Miocene eustasy derived from the mixed siliciclastic–carbonate stratigraphic record of the northeastern Australian margin. Earth Planet. Sci. Lett. 304, 455–467 (2011).

    Article  Google Scholar 

  18. Pekar, S. F. & DeConto, R. M. High-resolution ice-volume estimates for the Early Miocene: evidence for a dynamic ice sheet in Antarctica. Palaeogeogr. Palaeoclimatol. Palaeoecol. 231, 101–109 (2006).

    Article  Google Scholar 

  19. Lear, C. H., Elderfield, H. & Wilson, P. A. Cenozoic deep-sea temperatures and global ice volumes from Mg/Ca in benthic foraminiferal calcite. Science 287, 269–272 (2000).

    Article  Google Scholar 

  20. Bierman, P. R., Shakun, J. D., Corbett, L. B., Zimmerman, S. R. & Rood, D. H. A persistent and dynamic East Greenland ice sheet over the past 7.5 million years. Nature 540, 256–260 (2016).

    Article  Google Scholar 

  21. Warny, S. et al. Palynomorphs from a sediment core reveal a sudden remarkably warm Antarctica during the Middle Miocene. Geology 37, 955–958 (2009).

    Article  Google Scholar 

  22. Sangiorgi, F. et al. Southern Ocean warming and Wilkes Land ice sheet retreat during the Mid-Miocene. Nat. Commun. 9, 317 (2018).

    Article  Google Scholar 

  23. De Boer, B., de Wal, R. S. W., Bintanja, R., Lourens, L. J. & Tuenter, E. Cenozoic global ice-volume and temperature simulations with 1-D ice-sheet models forced by benthic δ18O records. Ann. Glaciol. 51, 23–33 (2010).

    Article  Google Scholar 

  24. Kochhann, K. G. D., Holbourn, A., Kuhnt, W. & Xu, J. Eastern equatorial Pacific benthic foraminiferal distribution and deep water temperature changes during the Early to Middle Miocene. Mar. Micropaleontol. 133, 28–39 (2017).

    Article  Google Scholar 

  25. Shevenell, A. E., Kennett, J. P. & Lea, D. W. Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: a Southern Ocean perspective. Geochem. Geophys. Geosyst. 9, Q02006 (2008).

    Article  Google Scholar 

  26. Waelbroeck, C. et al. Sea-level and deep water temperature changes derived from benthic foraminifera isotopic records. Quat. Sci. Rev. 21, 295–305 (2002).

    Article  Google Scholar 

  27. Knorr, G. & Lohmann, G. Climate warming during Antarctic ice sheet expansion at the Middle Miocene transition. Nat. Geosci. 7, 376–381 (2014).

    Article  Google Scholar 

  28. Valdes, P. J. et al. The BRIDGE HadCM3 family of climate models: HadCM3@ Bristol v1.0. Geosci. Model Dev. 10, 3715–3743 (2017).

    Article  Google Scholar 

  29. Feakins, S. J., Warny, S. & Lee, J.-E. Hydrologic cycling over Antarctica during the Middle Miocene warming. Nat. Geosci. 5, 557–560 (2012).

    Article  Google Scholar 

  30. Rees-Owen, R. L. et al. The last forests on Antarctica: reconstructing flora and temperature from the Neogene Sirius Group, Transantarctic Mountains. Org. Geochem. 118, 4–14 (2018).

    Article  Google Scholar 

  31. Passchier, S. et al. Early Eocene to Middle Miocene cooling and aridification of East Antarctica. Geochem. Geophys. Geosyst. 14, 1399–1410 (2013).

    Article  Google Scholar 

  32. Sosdian, S. M. et al. Constraining the evolution of Neogene ocean carbonate chemistry using the boron isotope pH proxy. Earth Planet. Sci. Lett. 498, 362–376 (2018).

    Article  Google Scholar 

  33. Paterson, W. S. B. The Physics of Glaciers (Elsevier, 2016).

  34. Phipps, S. J., Fogwill, C. J. & Turney, C. S. M. Impacts of marine instability across the East Antarctic ice sheet on Southern Ocean dynamics. Cryosphere 10, 2317–2328 (2016).

    Article  Google Scholar 

  35. Rugenstein, M. et al. Equilibrium climate sensitivity estimated by equilibrating climate models. Geophys. Res. Lett. 47, e2019GL083898 (2020).

    Article  Google Scholar 

  36. Frigola, A., Prange, M. & Schulz, M. Boundary conditions for the Middle Miocene climate transition (MMCT v1.0). Geosci. Model Dev. 11, 1607–1626 (2018).

    Article  Google Scholar 

  37. Hamon, N. et al. Growth of subtropical forests in Miocene Europe: the roles of carbon dioxide and Antarctic ice volume. Geology 40, 567–570 (2012).

    Article  Google Scholar 

  38. Levy, R. et al. Antarctic ice sheet sensitivity to atmospheric CO2 variations in the Early to Mid-Miocene. Proc. Natl Acad. Sci. USA 113, 3453–3458 (2016).

    Article  Google Scholar 

  39. Colleoni, F. et al. Spatio-temporal variability of processes across Antarctic ice-bed–ocean interfaces. Nat. Commun. 9, 2289 (2018).

    Article  Google Scholar 

  40. Van der Veen, C. J. Fracture mechanics approach to penetration of surface crevasses on glaciers. Cold Reg. Sci. Technol. 27, 31–47 (1998).

    Article  Google Scholar 

  41. DeConto, R. M. & Pollard, D. Contribution of Antarctica to past and future sea-level rise. Nature 531, 591 (2016).

    Article  Google Scholar 

  42. Deline, P. Change in surface debris cover on Mont Blanc massif glaciers after the ‘Little Ice Age’ termination. Holocene 15, 302–309 (2005).

    Article  Google Scholar 

  43. Fickert, T., Friend, D., Grüninger, F., Molnia, B. & Richter, M. Did debris-covered glaciers serve as Pleistocene refugia for plants? A new hypothesis derived from observations of recent plant growth on glacier surfaces. Arct. Antarct. Alp. Res 39, 245–257 (2007).

    Article  Google Scholar 

  44. Zale, R. et al. Growth of plants on the late Weichselian ice-sheet during Greenland interstadial-1? Quat. Sci. Rev. 185, 222–229 (2018).

    Article  Google Scholar 

  45. Dickson, J. H. & Johnson, R. E. Mosses and the beginning of plant succession on the Walker Glacier, southeastern Alaska. Lindbergia 37, 60–65 (2014).

    Article  Google Scholar 

  46. Gölles, T., Bøggild, C. E. & Greve, R. Ice sheet mass loss caused by dust and black carbon accumulation. Cryosphere 9, 1845–1856 (2015).

    Article  Google Scholar 

  47. Williamson, C. J. et al. Algal photophysiology drives darkening and melt of the Greenland ice sheet. Proc. Natl Acad. Sci. USA 117, 5694–5705 (2020).

  48. De Vleeschouwer, D., Vahlenkamp, M., Crucifix, M. & Pälike, H. Alternating Southern and Northern Hemisphere climate response to astronomical forcing during the past 35 m.y. Geology 45, 375–378 (2017).

    Article  Google Scholar 

  49. 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 

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

    Article  Google Scholar 

  51. Cox, P. M. Description on the TRIFFID Dynamic Global Vegetation Model Technical Report 24 (Hadley Centre, Met Office, 2001).

  52. Gordon, C. et al. The simulation of SST, sea ice extents and ocean heat transports in a version of the Hadley Centre coupled model without flux adjustments. Clim. Dyn. 16, 147–168 (2000).

    Article  Google Scholar 

  53. Jones, C. A fast ocean GCM without flux adjustments. J. Atmos. Ocean. Technol. 20, 1857–1868 (2003).

    Article  Google Scholar 

  54. Gent, P. R. & McWilliams, J. C. Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr. 20, 150–155 (1990).

    Article  Google Scholar 

  55. Pacanowski, R. & Philander, S. Parameterization of vertical mixing in numerical models of tropical oceans. J. Phys. Oceanogr. 11, 1443–1451 (1981).

    Article  Google Scholar 

  56. De Boer, A. M. & Hogg, A. M. Control of the glacial carbon budget by topographically induced mixing. Geophys. Res. Lett. 41, 4277–4284 (2014).

    Article  Google Scholar 

  57. Markwick, P. J. in Deep-Time Perspectives on Climate Change: Marrying the Signal from Computer Models and Biological Proxies (eds Williams, M. et al.) 251–312 (The Geological Society, 2007).

  58. Bradshaw, C. D. et al. The relative roles of CO2 and palaeogeography in determining Late Miocene climate: results from a terrestrial model–data comparison. Clim. Past 8, 715–786 (2012).

    Article  Google Scholar 

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Acknowledgements

C.D.B. and D.J.L. were supported by NERC grant NE I006281/1. C.H.L. and S.M.S. were supported by NERC grant NE/I006427/1. A.M.deB. and C.D.B. gratefully acknowledge support from the Swedish Research Council project [2016-03912]. This work was carried out using the computational facilities of the Advanced Computing Research Centre, University of Bristol: http://www.bristol.ac.uk/acrc/. We thank D. Suri, chief operational meteorologist, Met Office; G. Guentchev, senior scientist, Met Office; S. Feakins; and T. Naish for feedback on earlier drafts of this manuscript. We also thank E. Gasson for providing a plot of his ice-sheet model results13.

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Authors and Affiliations

  1. Met Office Hadley Centre, Fitzroy Road, Exeter, UK

    Catherine D. Bradshaw

  2. The Global Systems Institute, University of Exeter, Exeter, UK

    Catherine D. Bradshaw

  3. BRIDGE, School of Geographical Sciences, University of Bristol, Bristol, UK

    Catherine D. Bradshaw & Daniel J. Lunt

  4. Department of Geological Sciences, Stockholm University, Stockholm, Sweden

    Catherine D. Bradshaw, Helen K. Coxall & Agatha M. de Boer

  5. NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway

    Petra M. Langebroek

  6. School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK

    Caroline H. Lear & Sindia M. Sosdian

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Contributions

C.D.B., C.H.L. and D.J.L. conceived the project and directed the research with the assistance of A.M.deB.; C.D.B. conducted and interpreted the modelling with the assistance of D.J.L., A.M.deB. and P.M.L.; C.D.B compiled and interpreted the proxy records with the assistance of C.H.L., A.M.deB., H.K.C. and S.M.S.; C.D.B. led the writing of the paper. All authors contributed to writing the manuscript.

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Correspondence to Catherine D. Bradshaw.

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The authors declare no competing interests.

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Peer review information Nature Geoscience thanks Sarah Feakins, Tim Naish and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: James Super.

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Extended data

Extended Data Fig. 1 Benthic (Cibicidoides spp.) oxygen isotope δ18Oc and deep water temperatures (DWT) changes from the Mg/Ca proxy through the Middle Miocene.

a Site 761 in the Indian Ocean8, b Site 1171 in the Southern Ocean25. Data are plotted on their respective age models. DWT uncertainty is ±4 °C; relative values are considered more robust than absolutes.

Supplementary information

Supplementary Information

Supplementary note, discussion, methods, references, Figs. 1–68 and Tables 1–4.

Supplementary Table S5-S11

Supplementary Tables 5–11.

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Bradshaw, C.D., Langebroek, P.M., Lear, C.H. et al. Hydrological impact of Middle Miocene Antarctic ice-free areas coupled to deep ocean temperatures. Nat. Geosci. 14, 429–436 (2021). https://doi.org/10.1038/s41561-021-00745-w

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