武汉市东湖沉积物的磁性特征与周围环境之间的关系

通过对武汉市东湖沉积物114个样品的磁性分析,结合扫描电镜图像和区域环境背景,发现东湖主湖区之一的郭郑湖沉积物的磁性载体相对含量较少,以磁铁矿为主,同时含有钛磁铁矿以及铁的硫化物等,它们一部分来自于湖区周围的各种碎屑物质,一部分来自于呈球形的工业尘埃降落以及城市污水和交通尾气,这些磁性颗粒粗细不均,平均频率磁化率系数χFD%为3.03%.相对于郭郑湖,另一个子湖塘林湖沉积物的磁性载体(多畴磁铁矿)含量较多,平均χFD%为1.37%,且来源以呈球形的工业尘埃降落为主,少部分来自于湖区周围的碎屑物质.利用此种方法,可以评价污染物质的来源对城市内陆湖泊的影响等.

Relationship Between Magnetic Properties and Circumference Environment of Lake Sediments of Donghu, Wuhan City

Combining with the images of scanning electron microscopy(SEM) and the regional environmental background,the analysis of magnetic carrier properties of 114 samples of Donghu Lake sediments reveals that the sediments of Guozheng Lake have less magnetic carriers than those of Tanglin Lake,both of which are sub-lakes of Donghu Lake.Magnetic carrier materials of Guozheng Lake are more magnetite and less titanomagnetite,sulphide of the iron.Some of them come from the detrital chipping materials of the lake circumference,others are from spherical industrial dust,municipal sewage and tail gas of traffic.These grain sizes are uneven,their average ratio of frequency dependent susceptibility(χFD%) is 3.03%.Magnetic carriers of Tanglin Lake are multidomain magnetite,their average χFD% is 1.37%.These magnetic materials come mainly from spherical industry dust,partially from detrital chipping materials of the lake circumference.By employing this method,the paper estimate the source of pollutants and the impacts of human activities and natural process on inner city lakes can be estimated.