Abstract

The approximately 10,000-year-long Last Glacial Maximum, before the termination of the last ice age, was the coldest period in Earth’s recent climate history1. Relative to the Holocene epoch, atmospheric carbon dioxide was about 100 parts per million lower and tropical sea surface temperatures were about 3 to 5 degrees Celsius lower2,3. The Last Glacial Maximum began when global mean sea level (GMSL) abruptly dropped by about 40 metres around 31,000 years ago4 and was followed by about 10,000 years of rapid deglaciation into the Holocene1. The masses of the melting polar ice sheets and the change in ocean volume, and hence in GMSL, are primary constraints for climate models constructed to describe the transition between the Last Glacial Maximum and the Holocene, and future changes; but the rate, timing and magnitude of this transition remain uncertain. Here we show that sea level at the shelf edge of the Great Barrier Reef dropped by around 20 metres between 21,900 and 20,500 years ago, to −118 metres relative to the modern level. Our findings are based on recovered and radiometrically dated fossil corals and coralline algae assemblages, and represent relative sea level at the Great Barrier Reef, rather than GMSL. Subsequently, relative sea level rose at a rate of about 3.5 millimetres per year for around 4,000 years. The rise is consistent with the warming previously observed at 19,000 years ago1,5, but we now show that it occurred just after the 20-metre drop in relative sea level and the related increase in global ice volumes. The detailed structure of our record is robust because the Great Barrier Reef is remote from former ice sheets and tectonic activity. Relative sea level can be influenced by Earth’s response to regional changes in ice and water loadings and may differ greatly from GMSL. Consequently, we used glacio-isostatic models to derive GMSL, and find that the Last Glacial Maximum culminated 20,500 years ago in a GMSL low of about −125 to −130 metres.

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References

  1. 1.

    Clark, P. U. et al. The Last Glacial Maximum. Science 325, 710–714 (2009).

  2. 2.

    Felis, T. et al. Intensification of the meridional temperature gradient in the Great Barrier Reef following the Last Glacial Maximum. Nat. Commun. 5, 4102 (2014).

  3. 3.

    Mix, A. C., Bard, E. & Schneider, R. Environmental processes of the ice age: land, oceans, glaciers (EPILOG). Quat. Sci. Rev. 20, 627–657 (2001).

  4. 4.

    Lambeck, K., Rouby, H., Purcell, A., Sun, Y. & Sambridge, M. Sea level and global ice volumes from the Last Glacial Maximum to the Holocene. Proc. Natl Acad. Sci. USA 111, 15296–15303 (2014).

  5. 5.

    Yokoyama, Y., Lambeck, K., DeDeckker, P., Johnston, P. & Fifield, L. K. Timing of the Last Glacial Maximum from observed sea-level minima. Nature 406, 713–716 (2000).

  6. 6.

    Fairbanks, R. G. A 17,000-year glacio-eustatic sea level record: influence of glacial melting dates on Younger Dryas event and deep ocean circulation. Nature 342, 637–642 (1989).

  7. 7.

    Bard, E., Hamelin, B. & Fairbanks, R. G. U–Th ages obtained by mass spectrometry in corals from Barbados: sea level during the past 130,000 years. Nature 346, 456–458 (1990).

  8. 8.

    Hanebuth, T., Stattegger, K. & Grootes, P. M. Rapid flooding of the Sunda Shelf: a late-glacial sea-level record. Science 288, 1033–1035 (2000).

  9. 9.

    De Deckker, P. & Yokoyama, Y. Micropalaeontological evidence for Late Quaternary sea-level changes in Bonaparte Gulf, Australia. Global Planet. Change 66, 85–92 (2009).

  10. 10.

    Nakada, M., Okuno, J. & Yokoyama, Y. Total meltwater volume since the Last Glacial Maximum and viscosity structure of Earth’s mantle inferred from relative sea level changes at Barbados and Bonaparte Gulf and GIA-induced J2. Geophys. J. Int. 204, 1237–1253 (2016).

  11. 11.

    Weigelt, P., Steinbauer, M. J., Cabral, J. S. & Kreft, H. Late Quaternary climate change shapes island biodiversity. Nature 532, 99–102 (2016).

  12. 12.

    Webster, J. M. et al. Response of the Great Barrier Reef to sea level and environmental changes over the past 30 ka. Nat. Geosci. 11, 426–432 (2018).

  13. 13.

    Yokoyama, Y. & Esat, T. M. in Handbook of Sea-Level Research (eds Shennan, I., Long, A. & Horton, B.) Ch. 7, 104–124 (John Wiley & Sons, Oxford, 2015).

  14. 14.

    Deschamps, P. et al. Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago. Nature 483, 559–564 (2012).

  15. 15.

    Bard, E., Hamelin, B. & Delanghe-Sabatier, D. Deglacial meltwater pulse 1B and Younger Dryas sea levels revisited with boreholes at Tahiti. Nature 327, 1235–1237 (2010).

  16. 16.

    Clark, P. U., McCabe, A. M., Mix, A. C. & Weaver, A. J. Rapid rise of sea level 19,000 years ago and its global implications. Science 304, 1141–1144 (2004).

  17. 17.

    MARGO Project Members. Constraints on the magnitude and patterns of ocean cooling at the Last Glacial Maximum. Nat. Geosci. 2, 127–132 (2009).

  18. 18.

    Cutler, K. B. et al. Rapid sea-level fall and deep ocean temperature change since the last interglacial period. Earth Planet. Sci. Lett. 206, 253–271 (2003).

  19. 19.

    Peltier, W. R. & Fairbanks, R. G. Global glacial ice volume and Last Glacial Maximum duration from an extended Barbados sea level record. Quat. Sci. Rev. 25, 3322–3337 (2006).

  20. 20.

    Grant, K. M. et al. Rapid coupling between ice volume and polar temperature over the past 150,000 years. Nature 491, 744–747 (2012).

  21. 21.

    Abe-Ouchi, A. et al. Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volume. Nature 500, 190–193 (2013).

  22. 22.

    Philippon, G. et al. Evolution of Antarctic ice sheet throughout the last deglaciation: a study with a new coupled climate—north and south hemisphere ice sheet model. Earth Planet. Sci. Lett. 248, 750–758 (2006).

  23. 23.

    Anderson, J. B. et al. Ross Sea paleo-ice sheet drainage and deglacial history during and since the LGM. Quat. Sci. Rev. 100, 31–54 (2014).

  24. 24.

    Yokoyama, Y. et al. Widespread collapse of the Ross Ice Shelf during the late Holocene. Proc. Natl Acad. Sci. USA 113, 2354–2359 (2016).

  25. 25.

    Lambeck, K., Purcell, A. & Zhao, S. The North American Late Wisconsin ice sheet and mantle viscosity from glacial rebound analyses. Quat. Sci. Rev. 158, 172–210 (2017).

  26. 26.

    Clark, P. U. & Tarasov, L. Closing the sea level budget at the Last Glacial Maximum. Proc. Natl Acad. Sci. USA 111, 15861–15862 (2014).

  27. 27.

    .Clark, P. U., Hostetler, S. W., Pisias, N. G., Schmittner, A. & Meissner, K. J. in Ocean Circulation (eds Schmittner, A., Chiang, J. C. H. & Hemming, S. R.) 209–246 (Geophysical Monograph 173, American Geophysical Union, Washington, 2007).

  28. 28.

    Brook, E. J. et al. Timing of millennial-scale climate change at Siple Dome, West Antarctica, during the last glacial period. Quat. Sci. Rev. 24, 1333–1343 (2005).

  29. 29.

    Yokoyama, Y. & Esat, T. M. Global climate and sea level-enduring variability and rapid fluctuations over the past 150,000 years. Oceanography 24, 54–69 (2011).

  30. 30.

    Paillard, D. Quaternary glaciations: from observations to theories. Quat. Sci. Rev. 107, 11–24 (2015).

  31. 31.

    Camoin, G. F. et al. Reef response to sea-level and environmental changes during the last deglaciation. IODP Expedition 310 “Tahiti Sea Level”. Geology 40, 643–646 (2012).

  32. 32.

    Webster, J. M., Yokoyama, Y., Cotterill, C. & the Expedition 325 Scientists. Great Barrier Reef Environmental Changes. http://publications.iodp.org/proceedings/325/325title.htm (Proc IODP 325, Integrated Ocean Drilling Program, 2011).

  33. 33.

    Abbey, E., Webster, J. M. & Beaman, R. J. Geomorphology of submerged reefs on the shelf edge of the Great Barrier Reef: the influence of oscillating Pleistocene sea-levels. Mar. Geol. 288, 61–78 (2011).

  34. 34.

    Bridge, T. C. L. et al. Topography, substratum and benthic macrofaunal relationships on a tropical mesophotic shelf margin, central Great Barrier Reef, Australia. Coral Reefs 30, 143–153 (2011).

  35. 35.

    Yokoyama, Y. et al. IODP Expedition 325: Great Barrier Reefs Reveals Past Sea-Level, Climate and Environmental Changes since the Last Ice Age. Sci. Drill. 12, 32–45 (2011).

  36. 36.

    Cabioch, G., Montaggioni, L. F., Faure, G. & Ribaud-Laurenti, A. Reef coralgal assemblages as recorders of paleobathymetry and sea-level changes in the Indo-Pacific province. Quat. Sci. Rev. 18, 1681–1695 (1999).

  37. 37.

    Dechnik, B. et al. The evolution of the Great Barrier Reef during the Last Interglacial Period. Global Planet. Change 149, 53–71 (2017).

  38. 38.

    Yokoyama, Y., Miyairi, Y., Matsuzaki, H. & Tsunomori, F. Relation between acid dissolution time in the vacuum test tube and time required for graphitization for AMS target preparation. Nucl. Instrum. Methods B 259, 330–334 (2007).

  39. 39.

    Hirabayashi, S., Yokoyama, Y., Suzuki, A., Miyairi, Y. & Aze, T. Multidecadal oceanographic changes in the western Pacific detected through high-resolution bomb-derived radiocarbon measurements on corals. Geochem. Geophys. Geosyst. 18, 1608–1617 (2017).

  40. 40.

    Fallon, S. J., Fifield, L. K. & Chappell, J. M. The next chapter in radiocarbon dating at the Australian National University: status report on the single stage AMS. Nucl. Instrum. Methods B 268, 898–901 (2010).

  41. 41.

    Druffel, E. R. M. & Griffin, S. Variability of surface ocean radiocarbon and stable isotopes in the southwestern Pacific. J. Geophys. Res. Oceans 104, 23607–23613 (1999).

  42. 42.

    Reimer, P. J. et al. INTCAL13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon 55, 1869–1887 (2013).

  43. 43.

    Esat, T. M. Charge collection thermal ion mass spectrometry of thorium. Int. J. Mass Spectrom. Ion Process. 148, 159–170 (1995).

  44. 44.

    Stirling, C. H., Esat, T. M., Lambeck, K. & McCulloch, M. T. Timing and duration of the last interglacial; evidence for a restricted interval of widespread coral reef growth. Earth Planet. Sci. Lett. 160, 745–762 (1998).

  45. 45.

    Cheng, H. et al. The half-lives of uranium-234 and thorium-230. Chem. Geol. 169, 17–33 (2000).

  46. 46.

    Stirling, C. H., Esat, T. M., McCulloch, M. T. & Lambeck, K. High-precision U-series dating of corals from Western Australia and implications for the timing and duration of the Last Interglacial. Earth Planet. Sci. Lett. 135, 115–130 (1995).

  47. 47.

    Thomas, A. L. et al. Penultimate deglacial sea level timing from uranium/thorium dating of Tahitian corals. Science 324, 1186–1189 (2009).

  48. 48.

    O’Leary, M. J. et al. Ice sheet collapse following a prolonged period of stable sea level during the last interglacial. Nat. Geosci. 6, 796–800 (2013).

  49. 49.

    Taylor, S. R. & McLennan, S. M. The Continental Crust: Its Composition and Evolution: An Examination of the Geochemical Record Preserved in Sedimentary Rocks (Blackwell Scientific, Oxford, 1985).

  50. 50.

    Okuno, J., Nakada, M., Ishii, M. & Miura, H. Vertical tectonic crustal movements along the Japanese coastlines inferred from late Quaternary and recent relative sea-level changes. Quat. Sci. Rev. 91, 42–61 (2014).

  51. 51.

    Dziewonski, A. M. & Anderson, D. L. Preliminary reference Earth model (PREM). Phys. Earth Planet. Inter. 25, 297–356 (1981).

  52. 52.

    Lambeck, K., Purcell, A., Johnston, P., Nakada, M. & Yokoyama, Y. Water-load definition in the glacio-hydro-isostatic sea-level equation. Quat. Sci. Rev. 22, 309–318 (2003).

  53. 53.

    Boulton, G. S., Dongelmans, P., Punkari, M. & Broadgate, M. Palaeoglaciology of an ice sheet through a glacial cycle: the European ice sheet through the Weichselian. Quat. Sci. Rev. 20, 591–625 (2001).

  54. 54.

    Lambeck, K., Smither, C. & Johnston, P. Sea-level change, glacial rebound and mantle viscosity for northern Europe. Geophys. J. Int. 134, 102–144 (1998).

  55. 55.

    Lambeck, K., Purcell, A., Zhao, J. & Svensson, N.-O. The Scandinavian ice sheet: from MIS 4 to the end of the Last Glacial Maximum. Boreas 39, 410–435 (2010).

  56. 56.

    Milne, G. A. & Mitrovica, J. X. Post glacial sea-level change on a rotating earth. Geophys. J. Int. 133, 1–19 (1998).

  57. 57.

    Nakada, M. & Lambeck, K. Late Pleistocene and Holocene sea-level change in the Australian region and mantle rheology. Geophys. J. 96, 497–517 (1989).

  58. 58.

    Lambeck, K. & Nakada, M. Late Pleistocene and Holocene sea-level change along the Australian coast. Global Planet. Change 3, 143–176 (1990).

  59. 59.

    Yokoyama, Y., Purcell, A., Marshall, J. F. & Lambeck, K. Sea-level during the early deglaciation period in the Great Barrier Reef, Australia. Global Planet. Change 53, 147–153 (2006).

  60. 60.

    Bart, P., Krogmeier, B. J., Bart, M. P. & Tulaczyk, S. The paradox of a long grounding during West Antarctic Ice Sheet retreat in Ross Sea. Sci. Rep. 7, 1262 (2017).

  61. 61.

    Halberstadt, A. R. W., Simkins, L. M., Greenwood, S. L. & Anderson, J. B. Past ice-sheet behaviours: retreat scenarios and changing controls in the Ross Sea Antarctica. Cryosphere 10, 1003–1020 (2016).

  62. 62.

    Austermann, J., Mitrovica, J. X., Latychev, K. & Milne, G. A. Barbados-based estimate of ice volume at Last Glacial Maximum affected by subducted plate. Nat. Geosci. 6, 553–557 (2013).

  63. 63.

    Edwards, R. L. et al. A large drop in atmospheric 14C/12C and reduced melting in the Younger Dryas, documented with 230Th ages of corals. Science 260, 962–968 (1993).

  64. 64.

    Tarasov, L. & Peltier, W. R. Coevolution of continental ice cover and permafrost extent over the last glacial-interglacial cycle in North America. J. Geophys. Res. 112, F02S08 (2007).

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Acknowledgements

We thank the IODP and ECORD (European Consortium for Ocean Research Drilling) for drilling the GBR, and the Bremen Core Repository for organizing the onshore sampling party. Financial support of this research was provided by the JSPS KAKENHI (grant numbers JP26247085, JP15KK0151, JP16H06309 and JP17H01168), the Australian Research Council (grant number DP1094001), ANZIC, NERC grant NE/H014136/1 and Institut Polytechnique de Bordeaux. This paper is a contribution to the INQUA commission on Coastal and Marine Processes and the PAGES PALSEA2 programme.

Reviewer information

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

Author information

Affiliations

  1. Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan

    • Yusuke Yokoyama
    • , Yosuke Miyairi
    • , Chikako Sawada
    •  & Takahiro Aze
  2. Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Tokyo, Japan

    • Yusuke Yokoyama
  3. Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan

    • Yusuke Yokoyama
  4. Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, Australia

    • Tezer M. Esat
    •  & Stewart Fallon
  5. Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory, Australia

    • Tezer M. Esat
  6. Woods Hole Oceanographic Institution, Woods Hole, MA, USA

    • William G. Thompson
  7. University of Edinburgh, Edinburgh, UK

    • Alexander L. Thomas
  8. University of Sydney, Sydney, New South Wales, Australia

    • Jody M. Webster
  9. University Museum, University of Tokyo, Tokyo, Japan

    • Hiroyuki Matsuzaki
  10. National Institute of Polar Research, Tokyo, Japan

    • Jun’ichi Okuno
  11. Universidad de Granada, Granada, Spain

    • Juan-Carlos Braga
  12. Nagoya University, Nagoya, Japan

    • Marc Humblet
  13. Tohoku University, Sendai, Japan

    • Yasufumi Iryu
  14. University of California Santa Cruz, Santa Cruz, CA, USA

    • Donald C. Potts
  15. University of Ryukyu, Naha, Japan

    • Kazuhiko Fujita
  16. Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan

    • Atsushi Suzuki
  17. Kyushu University, Fukuoka, Japan

    • Hironobu Kan

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Contributions

Y.Y. and J.M.W. were co-chief scientists of Expedition 325. J.O. and Y.Y. conducted GIA modelling. Y.Y. and T.M.E. wrote the manuscript in collaboration with J.M.W., A.L.T., J.-C.B. and M.H., and the paper was refined by contributions from the rest of the co-authors.

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The authors declare no competing interests.

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Correspondence to Yusuke Yokoyama.

Extended data figures and tables

  1. Extended Data Fig. 1 Simplified classification of the main coralgal assemblages observed in the Expedition 325 cores.

    Shallow reef habitats are represented by coral assemblages when associated with thick crusts of aA1 coralline algae and vermetid gastropods (8). Deep, fore-reef slope settings are defined by coral assemblages cD when associated with thin crusts of aA3 and in the absence of aA1 and aA2. cA, massive/robust branching Isopora (1) and corymbose Acropora gr. humilis (2); cB, branching Seriatopora (3) and Acropora sp. (4); cC, massive/encrusting meruliniids (5); cD, encrusting to massive Porites (6) and encrusting Montipora; aA3, Mesophyllum and Lithothamnion (10); aA1, Porolithon onkodes (7); and aA2, thin P. onkodes, Porolithon gardineri, Harveylithon gr. munitum (9).

  2. Extended Data Fig. 2 Representative facies observed in the Expedition 325 cores.

    The main lithologies are divided into coral reef framework, (1)–(3), and detrital sedimentary facies, (4)–(8).

  3. Extended Data Fig. 3 Stratigraphic synthesis of inner terrace cores at Mackay.

    The vertical patterns in coral recovery, lithologies, coralgal assemblages and vermetid gastropods are summarized here. These data define a major hiatus (pink line) in reef development as the top of Reef 2 was exposed following the sea level fall to the LGM-b low-stand (see main text for details). Following deglacial sea level rise, reef growth was re-established as Reef 3b turned on when the shelf reflooded before this reef drowned after about 14 kyr ago (ka). (‘bst.’, boundstone; ‘mb’, microbialite; ‘unconsol.’, unconsolidated sediment; and ‘gastro’, gastropod.)

  4. Extended Data Fig. 4 Close-up core images showing the boundary between Reef 2 and Reef 3a.

    Cores M00033A-10R and 11R (HYD-01C) and M00055A-4R (NOG-1B) clearly define the nature of the Reef 2/Reef 3b boundary, which represents a major hiatus in reef growth (see Extended Data Fig. 3). This boundary is characterized by major changes in lithologies, coralgal assemblages and diagenetic features, including fresh water and meteoric cements (blue star) indicating that the top of Reef 2 has been subaerially exposed. (LMC, low-magnesium calcite; RD, reef-death events.)

  5. Extended Data Fig. 5 Evidence of subaerial exposure.

    The blocky low-magnesium calcite meteoric cement that is related to subaerial exposure is initially precipitated in the intergranular voids of grainstone in 55A 5R1. Then peloids (p) of high-magnesium calcite formed under marine conditions and filled the remaining voids when they were submerged following re-flooding. Scale bar, 100 µm.

  6. Extended Data Fig. 6 Timing and extent of the sea-level drop at LGM-b.

    Age versus depth plot showing the key in situ RSL data points from Hydrographer’s Passage (HYD-01C) (in blue) and Noggin Pass (NOG-01B) (in red). Accelerator mass spectrometer 14C ages derived from corals are indicated by open circles and those derived from coralline algae are indicated by crossed circles. U–Th coral ages are indicated by filled circles. Inflection points defining the maximum position of the RSL at HYD-01C and NOG-01B are also shown (see labels NO-5, 8, 9, and HY-3, 5, 6 in Supplementary Information, corresponding respectively to data points 11, 8, 1 and 9, 7, 5 on this figure; see also Fig. 3). The combined RSL envelope represented by the black lines (maximum and minimum positions) takes into account the uncertainties in the age (2σ), palaeowater depth and position in the core of each data point, which is illustrated by a coloured rectangle (blue for Hydrographer’s Passage and red for Noggin Pass) (see Methods for more details). If we were to omit the 14C data owing to possible unaccounted-for variability in local reservoir ages63, the LGM-b sea level drop defined by coral U–Th ages would be 1.5 kyr earlier at 23.5 ka, corresponding to an extended sea level drop over about 3 kyr at a rate of about 7 m kyr−1. Key RSL index points are as follows. 1, 325-M0053A-13R-1W 21-25 (20.51 ka, 117.93 m; NO-9). 2, 325-M0054B-06R-1W 64-67 (20.50 ka, 124.39 m). 3, 325-M0054B-07R-1W 5-9 (20.47 ka, 125.3 m). 4, 325-M0035A-18R-1W 10-15 (20.43 ka, 127.11 m). 5, 325-M0036A-18R-2W 8-10 (20.70 ka, 128.75 m; HY-6). 6, 325-M0054B-08R-2W 73-75 (22.13 ka, 128.54 m). 7, 325-M0033A-11R-CCW 5-11 (22.11 ka, 106.83 m; HY-5). 8, 325-M0055A-04R-1W 35-40b (21.87 ka, 103.13 m; NO-8). 9, 325-M0032A-10R-1W 18-20 (23.49 ka, 107.95 m, HY-3). 10, 325-M0033A-13R-CCW 1-3 (23.62 ka, 109.46 m). 11, 325-M0055A-04R-2W 99-105 (23.97 ka, 104.84 m; NO-5).

  7. Extended Data Fig. 7 GIA results for selected sites.

    Calculations, for selected far-field sites (af), using the ice model based on the lower-bound of RSL from GBR. GIA calculations implemented using parameters of upper-mantle viscosity and lithospheric thickness of 1020 Pa s and 70 km and lower-mantle viscosity of 1022 Pa s. However, the differences between data and calculations for the far-field sites of Tahiti (b), Bonaparte (c) and Sunda (d) indicate a better match with GIA when the higher RSL obtained from this study is used (Fig. 4) in calculating the global deglacial sea levels. The grey band represents the range of RSL predictions using GIA modelling with various earth parameters (lithospheric thickness H = 70 km, upper-mantle viscosity 1020–1021 Pa s, lower-mantle viscosity 1021–1023 Pa s), and a melting model (of ice history), which, in this case, was the MIN model. The red lines are for H = 70km, upper-mantle viscosity 2 × 1020 Pa s and lower-mantle viscosity 1022 Pa s. The blue lines show the case for H = 70 km, upper-mantle viscosity 2 × 1020 Pa s and lower-mantle viscosity 1023 Pa s. Vertical uncertainties are depth ranges for each sea level indicators and horizontal error bars are 2σ uncertainties for age estimations reported from the literature.

  8. Extended Data Fig. 8 Comparisons between the ANU GMSL and the present GBR-based GMSL.

    ad, Total (a), North America (b), Eurasia (c) and Antarctic (d) ice sheet growth and melting histories for the past 35 kyr inferred from the present study (red bands) are compared with previously reported model (blue line). The blue curves represent the ANU GMSL results4, whereas the red bands, covering a range of GBR-RSL-based GMSL, are from this work. During the transition from LGM-a to LGM-b, around 21 kyr ago, there is enhanced precipitation over the North American Ice Sheet and to a lesser extent over Antarctica, although, for the latter, the ice volume continues to build up, for longer, until the termination of LGM-b approximately 17 kyr ago. The manually adjusted nominal ANU ice model will influence our inferred melting history for each ice sheet. Furthermore, although the ANU model differs in some respects from other ice sheet reconstructions64, the results from these simulations are not very different.

  9. Extended Data Fig. 9 GIA model results for HYD and NOG with different viscosity settings.

    MAX (a) and MIN (b) represent the maximum and minimum extremes of GBR RSL. Blue and red bands are RSL ranges derived from our study for Hydrographer’s Passage (HYD) and Noggin Pass (NOG). Grey bands represent the range of predicted sea levels using the new ice model. Lithospheric thickness is fixed at 70 km, whereas mantle viscosities for the upper and lower mantle varied between 1020–1021 Pa s and 1021–1023 Pa s. RSL predictions for representative viscosities for HYD-01C and NOG-01B are shown as red and blue solid and dotted lines respectively. Vup and Vlow represent the upper- and lower-mantle viscosity values. (obs., observations.)

  10. Extended Data Table 1 Simplified coral and coralline algal assemblages and their likely palaeoenvironmental setting

Supplementary information

  1. Supplementary Data

    This file contains the radiocarbon and U–Th dating results and GMSL used in this study.

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https://doi.org/10.1038/s41586-018-0335-4

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