Late Pleistocene history of New Brunswick, Canada

Abstract

The glacial history of New Brunswick is poorly understood. Evidence for pre-Late Wisconsinan events is fragmentary, and the glacial striation record attributed to the Late Wisconsinan is extremely complicated. Early east and south-east trending ice-flow events are suggested to be of Early Wisconsinan age. There is some evidence to suggest that parts of the province may have been deglaciated during the Middle Wisconsiman. However, previously-identified nunatak zones in the Northern Miramichi Highlands and the Caledonian Highlands are reinterpreted as glaciated during the Late Wisconsinan. Late Wisconsinan glaciation appears to result from the action of regional ice sheets that shifted flow direction on an intermittent basis as well as late-stage local ice caps. Deglaciation began c . 14,000 BP with ice retreat to margins along the Bay of Fundy coast in south-western New Brunswick, and along the Baie des Chaleurs coast in the north-east. The ice margin may have persisted in these areas for several thousand years. South-western New Brunswick was deglaciated prior to the Younger Dryas, and an ice-dammed lake may have existed in the Saint John River valley (Glacial Lake Acadia). The timing of deglaciation in the rest of the province remains to be determined. There is some evidence to suggest the expansion or redevelopment of local ice caps during the Younger Dryas Chronozone, but the extent of Younger Dryas ice is unknown.