Controversy exists on the position of sea level along the NE margin of the Laurentide Ice Sheet between 10 and 18 ka. In addition, there are minimal constraints on the location of the ice front prior to the first mappable Late Pleistocene raised marine sediments date 10.7 ka. This research involves a detailed study of Late Quaternary sea level oscillations along the margin of the Laurentide Ice Sheet in the vicinity of Hudson Strait and Frobisher Bay, Arctic Canada. Previous field work suggested that significant oscillations of sea level occured over short intervals of time but these are difficult to resolve if one relies on dating shells in raised marine wediments. Using the "isolation" method for reconstructing detailed relative sea level curves, an approach which consists of coring a series of small lakes above the marine limit down to present sea level, changes in relative sea level and the paleoenvironments will be deduced from changes in diatom floras. Radiocarbon dating of small segments of cores close to transitions will be carried out by accelerator dating methods. As lakes will be cored beyond the 10.7 ka ice margin a focus of the research will be assessment of glacial/climate/sea level events across the Younger Dryas chron (ca 11-10ka). The subsequent period, between 8 and 10ka, was one of rapid ice sheet retreat and collapse and thus will serve as an analog for the hypothesized CO2 induced retreat of the West Antarctic Ice Sheet.