The Last Deglaciation of North America,
21,400 - 5700 years ago, animation

The most recent Ice Age began about 120,000 years ago, and gradually intensified with lots of variations over the next 100,000 years. It reached its maximum about 18,000 years ago. The melt-down was much more rapid, occurring between 18,000 and about 6000 years ago, i.e., a span of only about 12,000 years. This movie shows how the great Canadian Ice Sheet melted away at the end of that last Ice Age.

To view this movie, click on the image.

Download: North American Deglaciation Movie (29 MB)

This movie was created from the maps of Arthur Dyke of the Canadian Geological Survey, with minor additions from other sources. The animation was constructed by Prof. Tanya Atwater, U.C.S.B., with extensive advice and direction from Prof. Em. Stephen Porter, U. Washington.


The glacier reconstructions and most coastlines are from the map set in Dyke, A. S. (2004), "An outline of North American Deglaciation with emphasis on central and northern Canada" in Quaternary Glaciations- Extent and Chronology, Part II, p. 373-424, J. Ehlers and P. L. Gibbard, eds, Elsevier,

with additional data from Denton, G. H. and Hughes, T. J. (eds) 1981, The Last Great Ice Sheets, p. 263-317, J. Wiley & Sons, New York, 484 p.

Extents and variations of lakes in the Great Basin are from D. R. Curry, G. Atwood, and D. Mabey, 1983, Major Levels of Great Salt Lake and Lake Bonneville, Map 73, Utah Geological Survey; and from Morrison, R. D. (1965) "Quaternary geology of the Great Basin", in The Quaternary of the United States, H. Wright and D. Frey (eds), Princeton University Press , and R. D. Morrison (1964) Lake Lahontan: Geology of the Carson Desert, Prof. Paper 40, U.S. Geol. Survey.

C14 calibrations and coastlines not included on Arthur Dyke's maps were estimated using the Barbados sea level curve of Bard E, Hamelin BJ, Fairbanks RG, Zindler A (1990) "Calibration of the 14C timescale over the past 30,000 years using mass spectrometric U-Th ages from Barbados corals", Nature 345, p. 405-410.

Artist J. Iwerks assisted in rendering the glacial topography of the ice sheets.
Prof. J. Severinghaus, Scripps Inst. Oceanography, provided helpful scientific critiques and suggestions.

Continental Map templates are from O.D.S.N. Plate Tectonic Reconstruction Service at

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