【摘要】 根据高陵渭河河漫滩沉积剖面中105个样品的颗粒与有机质分析,Hg与CaCO3含量测定和史书记载的年代资料,研究了西安高陵渭河距今约120a来河漫滩沉积指示的洪水变化。结果表明,高陵渭河约120a来至少发生了16次大洪水,洪水规模存在一定差别,各次洪水一般代表了当年降水量的明显增加;高陵渭河河漫滩沉积中有机碳浓度、金属汞的含量、CaCO3含量变化显著,它们与颗粒大小之间有明显的相关性,沉积物粒度越细,其有机碳和重金属汞的含量越高,CaCO3含量越少。有机碳和重金属汞的含量变化能够间接指示洪水动力强弱变化和短暂降水量增加。汞含量变化表明,渭河汞污染发生时间相当晚。更多还原

【Abstract】 The paper has analyzed on the grain size,total organic carbon（TOC） content,Hg and CaCO₃ content of 105 samples from Weihe river deposits in Xi’an suburb,and hereby has studied the flood changes indicated by the deposit sequence over the past 120 years based on the chronology data recorded by historical books.Over the past 120 years there were at least 16 times big floods occurred in the study region,and their scales were different,which reflected the various amount of precipitation.The TOC,Hg and CaCO₃ contents change remarkably in profile,and they have close relation with the grain size variation.The finer the grain size of deposits,the higher content of TOC and Hg,and the less CaCO₃content.The changes of TOC and Hg contents can indirectly indicate the flood power change and the short precipitation increase.Besides,the Hg content change indicates that the Hg pollution in Weihe River occurred in relatively modern period.更多还原