Abstract
The areal extents of the Laurentide and Fennoscandian ice sheets during the Last Glacial Maximum (about 20,000 years ago) are well known1, but thickness estimates range widely, from high-domed2 to thin3, with large implications for our reconstruction of the climate system regarding, for example, Northern Hemisphere atmospheric circulation and global sea levels. This uncertainty stems from difficulties in determining the basal temperatures of the ice sheets and the shear strength of subglacial materials4, a knowledge of which would better constrain reconstructions of ice-sheet thickness. Here we show that, in the absence of direct data, the occurrence of ribbed moraines in modern landscapes can be used to determine the former spatial distribution of frozen- and thawed-bed conditions. We argue that ribbed moraines were formed by brittle fracture of subglacial sediments, induced by the excessive stress at the boundary between frozen- and thawed-bed conditions resulting from the across-boundary difference in basal ice velocity. Maps of glacial landforms from aerial photographs of Canada and Scandinavia reveal a concentration of ribbed moraines around the ice-sheet retreat centres of Quebec, Keewatin, Newfoundland and west-central Fennoscandia. Together with the evidence from relict landscapes that mark glacial areas with frozen-bed conditions, the distribution of ribbed moraines on both continents suggest that a large area of the Laurentide and Fennoscandian ice sheets was frozen-based—and therefore high-domed and stable—during the Last Glacial Maximum.
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References
Denton,G. H. & Hughes,T. J. (eds) The Last Great Ice Sheets (Wiley-Interscience, New York, 1981).
Budd,W. F. & Smith,I. N. in Sea Level, Ice, and Climatic Change (ed. Allison, I. ) 369–409 (Publ. 131, International Association of Hydrological Sciences, Washington DC, 1981).
Licciardi,J. M., Clark,P. U., Jenson,J. W. & MacAyeal,D. R. Deglaciation of a soft-bedded Laurentide Ice Sheet. Quat. Sci. Rev. 17, 427–448 (1998).
MacAyeal,D. R. Binge/purge oscillations of the Laurentide Ice Sheet as a cause of the North Atlantic's Heinrich events. Paleoceanography 8, 775–784 (1993).
Hooke,R. LeB. Basal temperatures in polar ice sheets - a qualitative review. Quat. Res. 7, 1–13 (1977).
Hughes,T. J. in Proc. 2nd Int. Conf. on Permafrost 213–223 (National Academy of Sciences, Washington DC, 1973).
Boulton,G. S. in Drumlin Symposium (eds Menzies, J. & Rose, J. ) 25–80 (Balkema, Rotterdam, 1987).
Lundqvist,J. Rogen moraine - an example of two-step formation of glacial landscapes. Sedim. Geol. 111, 27–40 (1997).
Boulton,G. S. & Clark,C. D. A highly mobile Laurentide Ice Sheet revealed by satellite images of glacial lineations. Nature 346, 813–817 (1990).
Prest,V. K., Grant,D. R. & Rampton,V. N. Glacial Map of Canada (Geological Survey of Canada, Ottawa, 1969).
Lagerbäck,R. & Robertsson,A. -M. Kettle holes - Stratigraphical archives for Weichselian geology and palaeoenvironment in northernmost Sweden. Boreas 17, 439–468 (1988).
Bouchard,M. A. Subglacial landforms and deposits in central and northern Quebec, Canada, with emphasis on Rogen moraines. Sedim. Geol. 62, 293–308 (1989).
Aylsworth,J. M. & Shilts,W. W. Glacial features around the Keewatin ice divide: Districts of Mackenzie and Keewatin. Geol. Surv. Can. Pap. 88-24, 1–21 (1989).
Hättestrand,C. Ribbed moraines in Sweden - distribution pattern and paleoglaciological implications. Sedim. Geol. 111, 41–56 (1997).
Hättestrand,C. & Kleman,J. Ribbed moraine formation. Quat. Sci. Rev. 18, 43–61 (1999).
Hutter,K. & Olunloyo,V. O. S. Basal stress concentrations due to abrupt changes in boundary conditions: a cause for high till concentration at the bottom of a glacier. Ann. Glaciol. 2, 29–33 (1981).
Kleman,J. & Borgström,I. Glacial land forms indicative of a partly frozen bed. J. Glaciol. 40, 255–264 (1994).
Kleman,J. Preservation of landforms under ice sheets and ice caps. Geomorphology 9, 19–32 (1994).
Dyke,A. S. Landscapes of cold-centred Late Wisconsinan ice caps, Arctic Canada. Prog. Phys. Geogr. 17, 223–247 (1993).
Sugden,D. E. & Watts,S. H. Tors, felsenmeer and glaciation in northern Cumberland Peninsula, Baffin Island. Can. J. Earth Sci. 14, 2817–2823 (1977).
Kleman,J., Borgström,I. & Hättestrand,C. Evidence for a relict glacial landscape in Quebec-Labrador. Palaeogeogr. Palaeoclimatol. Palaeoecol. 111, 217–228 (1994).
Dyke,A. S., Morris,T. F., Green,D. E. C. & England,J. Quaternary Geology of Prince of Wales Island Arctic Canada (Mem. 433, Geological Survey of Canada, Ottawa, 1992).
Nordkalott project Map of Quaternary Geology Sheet 2, Glacial Geomorphology, Northern Fennoscandia, 1:1 mill. (Geological Surveys of Finland, Norway and Sweden, Geological Survey of Sweden, Uppsala, 1986).
Sollid,J. L. & Torp,B. Nasjonalatlas for Norge, Glacialgeologisk kart over Norge, 1:1 mill. (Geografisk Institutt, Oslo, 1984).
Heine, J. T. & McTigue,D. F. A case for cold-based continental ice sheets—A transient thermal model. J. Glaciol. 42, 37–42 (1996).
Huybrechts,P. & T'siobbel,S. Thermomechanical modeling of Northern Hemisphere ice sheets with a two-level mass-balance parametrization. Ann. Glaciol. 21, 111–116 (1995).
Fisher,D. A. et al. Penny ice cap cores, Baffin Island, Canada, and the Wisconsin fore dome connection: Two states of Hudson Bay ice cover. Science 279, 692–695 (1998).
Kleman,J., Hättestrand,C., Borgström,I. & Stroeven,A. Fennoscandian palaeoglaciology reconstructed using a glacial geological inversion model. J. Glaciol. 43, 283–299 (1997).
Hughes,T. J. Can ice sheets trigger abrupt climatic change? Arct. Alp. Res. 28, 448–465 (1996).
Holmlund,P. & Fastook,J. A time-dependent glaciological model of the Weichselian Ice Sheet. Quat. Int. 27, 53–58 (1995).
Niemelä, J., Ekman I. & Lukashov,A. (eds) Quaternary Deposits of Finland and Northwestern part of Russian Federation and their Resources 1:1 mill (Geological Survey of Finland, and Institute of Geology, Karelian Science Centre of the Russian Academy of Sciences, Helsinki, 1993
Acknowledgements
This work was made possible through grants from the Swedish Natural Science Research Council and Carl Mannerfelts fund. We thank R. LeB. Hooke for comments on the manuscript.
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Kleman, J., Hättestrand, C. Frozen-bed Fennoscandian and Laurentide ice sheets during the Last Glacial Maximum. Nature 402, 63–66 (1999). https://doi.org/10.1038/47005
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DOI: https://doi.org/10.1038/47005
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