CGRG Bibliography of Canadian Geomorphology
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Author : Dionne, J-C.
Date : 1984
Title : An estimate of ice-drifted sediments based on the mud content of the ice cover at Montmagny, middle St. Lawrence Estuary.
Publication : Marine Geology
Issue : 57(1-4):
Page(s) : 149-166
Abstract
A mean thickness of 10 cm of mud was encountered in the ice cover over an area of approximately 20 km (super 2) . Thus, the total load of fines may be as much as 4 X 10 (super 6) tonnes (t). It is estimated that upon melting at break-up, about 15% of this load returns to the Montmagny tidal flat while the remaining volume is carried to the offshore zone. Considering breakup characteristics, it is estimated that about 1.5-2 X 10 (super 6) t of fines return to the turbidity zone while the remaining load is ice-drifted outside that zone. It is calculated that a load of 5-6 X 10 (super 6) t of sediment incorporated in the ice cover could escape from the turbidity zone annually. To this load should be added another 4 X 10 (super 6) t of suspended matter which come from the freezing in situ of the turbid water in the offshore zone. An annual output by ice drifting of 10 X 10 (super 6) t of sediment is thus likely and is in great contrast to the output during the ice-free season of approximately 1 X 10 (super 6) t. In the middle St. Lawrence Estuary, the annual output almost equals the input. Consequently the sediment budget is virtually in a state of equilibrium, which helps to explain why there is very little permanent mud deposition in the shore and offshore zones today.--Modified journal abstract.
Bibliography of Canadian Geomorphology