海滩表层磁性矿物空间分布特征和季节性变化——以青岛石老人海滩为例

    SPATIAL DISTRIBUTION OF MAGNETIC MINERALS ON THE BEACH AND ITS SEASONAL VARIATION: A CASE STUDY OF THE SHILAOREN BEACH IN QINGDAO

    • 摘要: 通过对石老人海滩不同季节表层沉积物体积磁化率的原地实测和所取表层样品粒度分级,结合海滩沉积动力环境因素综合分析得知,石老人海滩不同季节表层沉积物磁化率值总体上都表现出东高西低,滩肩高滩面低的趋势。海滩沉积物颗粒夏季比冬季细,分选好。海滩磁化率和沉积物粒度在海滩上的空间分布特征及其季节性变化存在一定联系。海滩的侵蚀沉积过程主要受冬夏季不同的波浪、沿岸流和风的作用影响。通常磁化率值高的区域为颗粒较细的侵蚀区,磁化率值低的区域为颗粒较粗的沉积区。磁学方法作为一种简便快捷低成本易操作的新方法,可以代替耗时的粒度和矿物分析,来分析海滩的沉积动力作用过程,识别海滩的侵蚀和沉积区域。

       

      Abstract: This paper surveyed the volume susceptibility and grain size distribution of surface sediments on the Shilaoren Beach in Qingdao formed in different seasons. Combined with the sediment hydrodynamic factors on the beach, it is revealed that the volume susceptibility is higher in the east and lower in the west, and higher in the berm and lower in the beach face. The deposits on the beach are finer in summer but coarser in winter. There is certain relationship between magnetic susceptibility and the characteristics of spatial distribution of sediment particle size on the beach. The susceptibility is related to the grain size, and effected by wave sorting, alongshore current and wind action. In general, high magnetic susceptibility values occur in the erosional area of finer sediments and low value in deposition areas with coarser particles. As a convenient new method of easy operation with low cost, the magnetism method can be used to replace the time-consuming grain size and mineral analysis, to study the beach sedimentary dynamic process and to identify erosional and depositional areas on a beach.

       

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