Data generated using freely-available satellite remote sensing observations from the USGS Earth Resources Observation Science Centre, together with a freely-available ice margin chronology from Dyke et al. (2003) Geological Survey of Canada Open File Report No. 1574. The map is published in the Journal of Maps: http://www.tandfonline.com/doi/full/10.1080/17445647.2014.912036 Published article in 'Nature' Volume 530 Feb 2016 with associated source data. https://dx.doi.org/10.1038/nature16947 Published paper in the Taylor Francis Online Journal with associated data. https://dx.doi.org/10.1080/17445647.2014.912036