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 Møhl, Niels Rud, and Árný E. Sveinbjörnsdóttir
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