This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beac...This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beach showed that magnetite（～150μm） is the dominant magnetic mineral.Surficial magnetic susceptibility values defined three zones：a lakeward region close to the water line（Zone 1）,the upper swash zone（Zone 2） and the region landwards of the upper swash zone （Zone 3）.Zone 2 showed the highest bulk and mass susceptibility（κ,χ） and the highest mass percentage of smaller grain-size（250μm） fractions in the bulk sand sample.Susceptibility（i.e.κandχ） values decreased and grain size coarsened from Zone 2 lakewards（into Zone 1） and landwards （into Zone 3）,and correlated with the distribution of the heavy mineral assemblage,most probably reflecting preferential separation of large,less dense particles by waves and currents both along and across the beach.The eroded western section of Cedar Beach showed much higher concentrations of heavy minerals including magnetite,and finer sand grain sizes than the accreting eastern section, suggesting that magnetic techniques could be used as a rapid,cost-effective way of examining erosion along sensitive coastline areas.展开更多
A numerical model of shoreline change of sand beaches based on long-term field wave data is proposed, the explicit and implicit finite difference forms of the model are described, and an application of the model is pr...A numerical model of shoreline change of sand beaches based on long-term field wave data is proposed, the explicit and implicit finite difference forms of the model are described, and an application of the model is presented. Results of the application indicate that the model is sensitive to the order of the input wave data, and that the effects of long-term wave series and the effects of the mean annual wave conditions on the model are different. Instead of a single wave condition, the wave series will make the calibration and the verification of the model more practical and the results of the model more reasonable.展开更多
A reformed numerical model based on the 'one-line theory' for beach deformation is presented. In this model, the change of beach slope during coastline procession is considered.A wave numerical model combined ...A reformed numerical model based on the 'one-line theory' for beach deformation is presented. In this model, the change of beach slope during coastline procession is considered.A wave numerical model combined with wave refraction, diffraction and reflection is used to simulate wave climate to increase numerical accuracy.The results show that the numerical model has a good precision based on the adequate field data. The results can be applied to practical engineering.展开更多
基金supported by funding from the 111 Project B07011 of Ministry of Education of China,the China Scholarship Council(CSC) to SWZ (NCIS No.2007103928)an NSERC grant to MTC. D.Chevalier is thanked for her help in sampling. Laboratory assistance was provided bv K.Kawasaki and S.Joshi
文摘This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beach showed that magnetite（～150μm） is the dominant magnetic mineral.Surficial magnetic susceptibility values defined three zones：a lakeward region close to the water line（Zone 1）,the upper swash zone（Zone 2） and the region landwards of the upper swash zone （Zone 3）.Zone 2 showed the highest bulk and mass susceptibility（κ,χ） and the highest mass percentage of smaller grain-size（250μm） fractions in the bulk sand sample.Susceptibility（i.e.κandχ） values decreased and grain size coarsened from Zone 2 lakewards（into Zone 1） and landwards （into Zone 3）,and correlated with the distribution of the heavy mineral assemblage,most probably reflecting preferential separation of large,less dense particles by waves and currents both along and across the beach.The eroded western section of Cedar Beach showed much higher concentrations of heavy minerals including magnetite,and finer sand grain sizes than the accreting eastern section, suggesting that magnetic techniques could be used as a rapid,cost-effective way of examining erosion along sensitive coastline areas.
基金This work is financially supported by the National Natural Science Foundation of China
文摘A numerical model of shoreline change of sand beaches based on long-term field wave data is proposed, the explicit and implicit finite difference forms of the model are described, and an application of the model is presented. Results of the application indicate that the model is sensitive to the order of the input wave data, and that the effects of long-term wave series and the effects of the mean annual wave conditions on the model are different. Instead of a single wave condition, the wave series will make the calibration and the verification of the model more practical and the results of the model more reasonable.
文摘A reformed numerical model based on the 'one-line theory' for beach deformation is presented. In this model, the change of beach slope during coastline procession is considered.A wave numerical model combined with wave refraction, diffraction and reflection is used to simulate wave climate to increase numerical accuracy.The results show that the numerical model has a good precision based on the adequate field data. The results can be applied to practical engineering.
