A new shoreline displacement model for the last 7 ka from eastern James Bay, Canada

The shoreline displacement history of the eastern James Bay lowlands in the last 7 ka has been investigated by means of AMS radiocarbon dating of sediments cored from wetlands. We present twelve radiocarbon dates on macrofossils from six sites spread along a gradient of increasing land age and elevation. Palynomorph analysis (pollen, spores, and dinoflagellate cysts) was used to define the isolation stratigraphy. During the last 7 ka the shoreline elevation has regressed at a decreasing rate. The rate of shoreline emergence was initially rapid (6. 5 m/ 100 yr) between 6850 and  6400 cal yr BP then slowed down to 1.4– 2 m/ 100 yr during the late Holocene. Examination of previous relative sea level data based upon mollusc shells reveals high levels of uncertainty that mask potential temporal variability.