Vegetational and climatic history of Nova Scotia. I. Radiocarbon-dated pollen profiles from Halifax, Nova Scotia

• Published in: Canadian Journal of Botany
• Main Author: Ogden III, J. Gordon
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1987
• Subjects: Plant Science; Betula nana; Tundra
• Online Access: http://dx.doi.org/10.1139/b87-205; http://www.nrcresearchpress.com/doi/pdf/10.1139/b87-205

Pollen and sediment stratigraphy of three lakes in the Halifax, N.S., area show similarities and differences related to morphometry and hydrology. Five radiocarbon dates from two of the cores provide sedimentation rate estimates ranging from 0.31 to 0.58 mm/year with an r 2 of 0.97. Organic sedimentation was initiated in lakes in the Halifax area about 12 000 years ago. Low pollen densities and high proportions of herbaceous and shrub pollen types imply open country or tundra-like vegetational cover until ca. 10 000 B.P. A possible Allerød-type late-glacial climatic oscillation is apparent from the sediment and pollen records. Small birch pollen (cf. Betula nana), pine, spruce, willow, and ericaceous pollen dominate the late-glacial (ca. 12 000–10 000 B.P.) predominantly inorganic section of the sediment cores. It is presumed from the pollen data that hemlock (Tsuga canadensis) invaded the catchment areas about 8000 years ago, and that beech (Fagus grandifolia) arrived about 5000 years ago. Thermophilous Appalachian elements (Nyssa, Carya, Juglans, and Tilia) have never been part of postglacial Nova Scotian forests.