Mirror on Greenland Archaeologists Uncover Clues to Why Vikings Abandoned Greenland SPIEGEL ONLINE refers to an interesting study with detail including dates which would be useful here The study itself seems to be Norse Greenland Dietary Economy ca AD 980 ca AD 1450 Introduction Jette Arneborg Niels Lynnerup Jan Heinemeier Jeppe M hl Niels Rud and rn E Sveinbj rnsd ttir Journal of the North Atlantic 2011 2012 Vol 3 Special Volume 3 Greenland Isotope Project Diet in Norse Greenland AD 1000 AD 1450 pg s 1 39 Possibly worthwhile but paywalled talk