Changes of the location of the major water masses have been interpreted from the range of different species of fossil molluscs. It is known that there were extensive peat deposits formed in areas where today there is little accumulation. Several syntheses have been attempted, and all point to large gaps in our knowledge of the climate of this time period. There has been little done using lake sediments, which must be the major source of information about past climates in the region. There has been some work done on processes of lake sedimentation, but the connection to climate change is not clear.
Pollen analysis is a major source of information about past climates.
In the United States and southern Canada, there are 100's of pollen diagrams, and quantitative syntheses of the change through time of the vegetation have been attempted. There is a fair bit known about treeline variations. Major areas of research activity have been the MacKenzie Delta region and northwestern Qu bec, where we have a good idea of the postglacial position of treeline. American groups have analysed many sites in Alaska. The situation in Labrador is confusing.