CGRG Bibliography of Canadian Geomorphology
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Author : Cioppa, M.; Gallaway, EA.; Hatfield, R.; and Trenhaile, A,
Date : 2010.
Title : Experimental sediment transport measurements at Point Pelee National Park.
Publication : CMOS-CGU Ottawa 2010. 44th Annual CMOS Congress, 36th Annual Scientific Meeting of CGU, 3rd Joint CMOS-CGU Congress. May 31-June 4, 2010. Ottawa, Ontario.
Issue :
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Abstract
Sediment erosion and transport are important factors in the creation of coastal landforms, beach configurations and sediment budgets; however, reliable ways to determine rates and directions are still being sought. Complicating factors include grain size, shape, and density, and the direction and velocity of wind, waves and offshore currents. For example, most attempts to estimate longshore sediment transport rates are dependent on models that do not accurately describe movement of the sediment in the swash zone. The magnetic susceptibility (MS) of magnetite is very high relative to other common minerals (e.g. quartz). MS measurements are rapid and accurate, making this technique an attractive proposition for tracking sediment movement. At three locations on the East Beach of Point Pelee National Park (PPNP), the movement of magnetite was tracked using a Bartington MS2D meter over a period of 24 hours, in an attempt to determine the rate of longshore transport in the swash zone. Wind and wave conditions were monitored during the period of the test. In the initial stage of the test, the peak value of MS (indicating maximum concentration of the magnetite) moved with directions and rates consistent with dominant wind direction and velocity, while in the second stage, the overall value of MS decreased, but the peak position did not change. Investigations of the magnetic properties of different size fractions of the sand showed that the magnetic material was concentrated in the finer grain size fractions. These results suggest that while sediment transport is occurring during the first stage, the second stage resulted from sorting and deposition (stabilization) of the finer-grained magnetite. However, the MS-determined transport rates are somewhat lower than those calculated from wind and wave climate data, indicating that further study of this technique is needed.
Bibliography of Canadian Geomorphology