Comparison of marine and terrestrial Holocene climatic reconstructions from northeastern North America

• Published in: The Holocene
• Main Authors: Sawada, M., Gajewski, K., de Vernal, Anne, Richard, Pierre
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 1999
• Subjects: Paleontology; Earth-Surface Processes; Ecology; Archeology; Global and Planetary Change; Hudson Bay; Ice Sheet; Tundra
• Online Access: http://dx.doi.org/10.1191/095968399671029755; http://journals.sagepub.com/doi/pdf/10.1191/095968399671029755

Quantitative climate reconstructions based on marine dinocysts and terrestrial pollen sequences are consistent through the Holocene in northeastern North America. Principal components analysis (PCA) indicates a large-scale climate signal in the dinocysts and pollen. The combined and separate analyses of marine and nearby terrestrial pollen sequences from Hudson Bay, Labrador and the St Lawrence estuary differentiate tun dra, boreal forest and deciduous forest assemblages in time and space. These analyses indicate that the marine pollen record reflects vegetation changes of the regional terrestrial environment and allows direct correlations between the marine and terrestrial stratigraphies. Sea-surface temperatures estimated from dinocysts and terres trial air temperatures from pollen using the method of modern analogs show that the three regions had differing climate histories associated with their location with respect to deglaciation and air mass boundaries. High frequency climatic changes reconstructed for the St Lawrence estuary and Gulf, and a cooling reconstructed for the period prior to 8000 yr BP, are less reliable due to the larger values of the dissimilarity coefficients. Prior to 6000 yr BP, cool temperatures reconstructed along the Labrador margins, both in the marine and terrestrial environments, are in agreement with climate simulations indicating the persistence of an anticyclone over the Québec-Labrador ice sheet. In both Labrador and northwestern Québec, a late-Holocene cooling affects sites in the forest-tundra, but is not evident in Boreal forest sites, suggesting movements in the mean position of the polar front.