武汉东湖现代沉积界面时间标定的磁化率与工业事件分析

Age Determination of Recent Sedimentation Boundary in the East Lake, Wuhan, Identified by Magnetic Susceptibility Measurements and Industrial Events

湖泊现代沉积特征界面高精度时间标定是进行综合环境研究的基础工作。本文通过东湖现代沉积五个样柱的磁化率、沉积界面、磁性物类型与武汉地区工业事件存在的对应关系 ,并结合空间分布特征 ,得出近 110年间东湖沉积速率存在由小增大的特点 ,并且确定两个早期沉积环境变化界面的时间约为 1740年和 1810年。研究表明 ,现代沉积物磁性特征与工业事件分析方法 ,不仅能准确标定沉积磁性界面的年代 。

Accurate determination of sedimentation boundary age in recent lake is a basic work relevant to environmental investigation. Based on the relationship of two industrial events and type of magnetic substance, magnetic susceptibility, depositional characteristics in five cores from the East Lake, Wuhan, Hubei, China, the changes of sedimentation rate have been recognized during a period of past 110 years and two historically events in A. D. 1740 and 1810. The boundaries between the layers attributed to changes in industrial activity around the lake. The study illustrates the value of magnetic susceptibility for identifying time planes in recent sediments, and obtains the difference of sedimentation rates in different period and, furthermore, discusses the cause of magnetic susceptibility influenced by the charge of magnetic substance.