麻豆传媒

The Eastern Shore of Nova Scotia is experiencing post-glacial rise in relative sea level, resulting in a transgressive coastal environment. Drowned estuaries are fronted by eroding drumlin headlands which provide a sediment source for barrier beach formation. The rate of this coastal transgression is largely dependent on the drumlin sediment supply, as determined from drumlin volumes, cliff erosion rates and the grainsize distribution of the drumlin tills.

Studies of Hartlen Point and Terminal Beach drumlins, and Lawrencetown Beach, were undertaken to determine whether present beaches are derived from existing drumlins, or are the cumulative result of previous drumlin erosion cycles. Drumlin volumes and cliff erosion rates were calculated from aerial photograph analysis and field measurements. The stratigraphy and correlation of the drumlin tills were determined from grainsize, colour variations, cliff mapping and existing literature. The sediment volume of Lawrencetown Beach was measured from aerial photographs, beach plain vibrocores and high resolution acoustic profiles of the shoreface sediments.

A sediment budget calculated for Terminal Beach drumlins and the adjacent Lawrencetown Beach, shows that the drumlins of the Eastern Shore do not appear to provide sufficient beach sediment volumes to form existing barrier beaches. The additional volume is concluded to be provided by onshore transport of previously eroded drumlin sediment.

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