Geosciences Working Group

During the last ice ages, Canada was almost completely covered by the mighty Laurentian Ice Sheet, whose retreat began about 18,000 years ago and was not completed until about 4000 years ago. Melting of the ice masses resulted in massive episodic "glacial runs," outbursts of huge sub- and periglacial meltwater accumulations into the northwest Atlantic. Five of these outbursts occurred through the glacial valley of the St. Lawrence Ice Stream and have been accurately reconstructed and dated for the first time using sediment cores from the Grand Banks of Newfoundland as part of the Bremen-Canadian graduate program ArcTrain. Geophysical, sedimentological and geochemical methods in combination provide a conclusive picture of the sequence of these events and the origin and characteristics of the sedimentary deposits known as "plumites".

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