Within the last year or two, I read “The Frozen Echo”, Greenland and the Exploration of North America ca A.D. 1000-1500 by Kirsten A. Searver, 1996
She studied Catholic Church records and discovered much interesting information on the Viking residents of Greenland. The church was interested in the tithes of all its people. Her maps show that they all lived prety much between 20-50 km from the permanent ice sheet the extent of which was and probably now is determined mainly by the temperature of the ocean water. I doubt if the “little ice age” was responsible for their disappearance.
Supposedly there are ‘Old World’ records of the Bishop of Vinland as well.